Investigation of Sphenoid Spine Morphometry for Skull Base Surgery and Relation to Foramen Spinosum Localization

Investigation of Sphenoid Spine Morphometry for Skull Base Surgery and Relation to Foramen Spinosum Localization | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Investigation of Sphenoid Spine Morphometry for Skull Base Surgery and Relation to Foramen Spinosum Localization Eda Duygu Ipek, Berrin Ozustun, Ilgaz Akdogan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3867864/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Our study aimed to investigate the sphenoid spine morphological characterization, as well as the distances to important surgical points and its relation to foramen spinosum localization. Methods On a total of 65 skulls, the distances of the sphenoid spine to articular tubercle, mastoid process, external opening of carotid canal, anterior edge of infratemporal crest, and the point where sphenosquamosus suture intersects with infratemporal crest were measured from both the right and left sides. The length of the sphenoid spine was measured and classified morphologically. Localization of foramen spinosum relation to sphenoid spine was evaluated. Results The sphenoid spine length was stastistically different which was found to be 6.71 ± 1.97 and 6.14 ± 1.93 on the rigt and left sides, respectively (p = 0.027). The most commonly encountered shape of the sphenoid spine on both sides was rectangular, followed by spine shape. The foramen spinosum was most frequently located anteromedially and least frequently located anterolaterally according to sphenoid spine. In our study, it was determined for the first time that the localization of the foramen spinosum is associated with the shape of the sphenoid spine on both the right (p = 0.012) and left (p = 0.016) sides. Conclusion Our study provides morphometric data on the sphenoid spine and reports the association between the localization of the foramen spinosum and the type of sphenoid spine. Sphenoid spine variations and their relationship with adjacent anatomical structures should be taken into consideration in middle cranial fossa surgeries. Sphenoid spine Foramen spinosum Infratemporal fossa Endoscopic approach Skull base Figures Figure 1 Figure 2 Figure 3 Introduction The sphenoid spine, described as spina ossis sphenoidalis in anatomy terminology, is a pointed protrusion extending downward from the junction of the squamosal and posterior borders of the greater wings of the sphenoid bone. Three ligaments, ligamentum sphenomandibulare, mallei anterius and pterygospinosus, two muscles, musculus tensor veli palatini and tensor tympani, are attached to the sphenoid spine. Furthermore, it is adjacent to the cartilaginous part of the external auditory canal and chorda tympani medially and to the auriculotemporal nerve laterally [ 4 ]. Technological advancements have significantly expanded the range of areas accessible through endoscopic approaches in skull base surgeries, but the complications attributed to these approaches have also increased proportionally [ 3 ]. The internal carotid artery (ICA) is the most feared structure by endoscopic surgeons for its complications in skull base surgeries. In particular, there is a lack of anatomical landmarks that allow the safe exposure of the cervical portion of the ICA, which is surrounded by soft tissues throughout the parapharyngeal area in infratemporal fossa and access to this segment of the ICA is less defined [ 3 , 7 ]. In endoscopic transpterygoid approach, the pterygoid plate, mandibular nerve, Eustachian tube, and styloid process have been reported as reliable landmarks for reaching the parapharyngeal ICA [ 2 ]. Liu et al. [ 8 ] reported that the sphenoid spine and foramen spinosum are anatomical landmarks for the cartilaginous and bony junction of the Eustachian tube, and parapharyngeal ICA was located immediately posteroinferior to the sphenoid spine. Li et al. [ 7 ] also found that the sphenoid spine, tympanic crest, vaginal process of tympanic bone were the closest anatomical landmarks to the parapharyngeal ICA in the endoscopic transmasticator approach. Li et al. [ 6 ] reported that in transoral nasopharyngectomy, it is mandatory to define the parapharyngeal ICA before transection of the Eustachian tube and the best landmarks definining it are the sphenoid spine, petrotympanic fissure and pterigoid hamulus. The foramen spinosum, in which the middle meningeal vessels and the meningeal branch of mandibular nerve pass through it to middle cranial fossa, is located in the greater wing of the sphenoid bone. It is named ‘spinosum’ due to its close proximity to sphenoid spine and is described in classical anatomy texts to be located on the anteromedial side of sphenoid spine [ 13 , 16 , 17 ]. Although it has been evaluated in very few studies in the literature and in its normal position (anteromedial), lateral and medial placements mostly, it is observed that the localization of foramen spinosum varies relation to the sphenoid spine [ 13 , 14 , 17 ]. The localization of the foramen spinosum is important in various procedures, such as endovascular embolization of dural arteriovenous fistulas and meningiomas through the middle meningeal artery [ 13 ], in bypass operations where middle meningeal artery is used as a graft [ 14 ]. Also, it has been reported that anatomical variations of the foramen spinosum may be associated with abnormal development of the middle meningeal artery [ 16 ]. Therefore, a more detailed understanding of the localization of the foramen spinosum is necessary in the preoperative assessment of possible changes in the trajectory of neurovascular structures. Sphenoid spine used as a landmark during infratemporal surgical approaches due to its close proximity to the foramen spinosum, parapharyngeal ICA, Eustachian tube and chorda tympani [ 17 ]. Despite its clinical importance, there is a lack of data in the literature regarding the anatomical variations of the sphenoid spine, and studies investigating its relationship with adjacent structures are insufficient. In the present study, considering the importance of the topography of sphenoid spine and foramen spinosum in skull base surgeries, it was aimed to examine more detail of the foramen spinosum localization relation to the sphenoid spine and morphometric analysis of sphenoid spine with related structures. Materials and Methods In this study, 65 adult skulls of unknown gender, obtained from the bone archive of Aydin Adnan Menderes University, Faculty of Medicine, Department of Anatomy, were used. Damaged skulls that did not allow examination of the targeted structures were not included in the study. The distance of the sphenoid spine to the tip of mastoid process (SMP), to the tip of tuberculum articulare (STA), to the anterior border of external orifice of the carotid canal (SCC), to the point where the sutura sphenosquamosa intersects the crista infratemporalis (SO), to the most lateral (SPFl) and medial (SPFm) endpoints of the petrotympanic fissure, to the sphenoidal tubercle (STS), and the length of the sphenoid spine (SL) were measured on the right and left sides, using a digital Vernier caliper with a precision of 0.01 mm. The morphological characterization of the sphenoid spine was classified into five types: spine, quadrangular, pyramidal, plate and cup shaped, as shown in Fig. 1 . The localization of the foramen spinosum relation to the sphenoid spine was examined from the basis cranii externa. A sagittal line was passed through the center of the foramen spinosum as shown in Fig. 2 . The location of the foramen spinosum was classified as medial (M), lateral (L), anterior (A), anteromedial (AM), anterolateral (AL) and anterior-on the line (AO), medial-on the line (MO) and lateral-on the line (LO). In M and L placement, the sagittal line passed through the medial and lateral sides of the sphenoid spine while intersected with the sphenoid spine in A placement. In the AM and AL placement, the foramen spinosum was in front of the sphenoid spine and the sagittal line was on the medial and lateral sides of the sphenoid spine, respectively. Skulls with a line transition similar to the M, L and A placement of the foramen spinosum, but where the middle meningeal artery groove was observed on the sphenoid spine root, were classified as MO, LO and AO, respectively. SPSS (Version 22.0, SPSS Inc., Chicago, IL, USA) program was used for statistical analysis of the data. The distribution pattern of the data was evaluated with the Kolmogorov Smirnov test and paired-t test was applied to compare the right and left morphometric parameters. Chi-square test was used to evaluate the localization of the foramen spinosum according to sphenoid spine morphological types. Results The descriptive statistics of the morphometric measurements we conducted are indicated in Table 1 . In comparing the morphometric measurements between the right and left sides, it was found that only the length of the sphenoid spine was statistically higher on the right side (p = 0.027). Table 1 Mean, minimum and maximum values of morphometric parameters Right side mean ± ss (min–max) n = 65 Left side mean ± ss (min–max) n = 65 p value (Sig. 2-tailed) STA 29.08 ± 2.67 (22.7–35.6) 28.57 ± 2.36 (22.1–34.3) 0.71 SMP 32.97 ± 2.79 (26.6–44,1) 33.67 ± 2.93 (25.8–41.4) 0.63 SPFl 23.98 ± 3.03 (17.5–30.4) 23.79 ± 2.68 (18-29.6) 0.602 SPFm 4.05 ± 1.27 (2.2–5.8) 4.21 ± 1.27 (2.1–6.3) 0.512 SO 29.98 ± 4.17 (21.3–40.4) 29.76 ± 4.01 (20.7–39.9) 0.635 SCC 6.53 ± 1.86 (2.2–11.1) 6.74 ± 2.28 (2.4–12.4) 0.426 STS 33.13 ± 3.57 (20.5–41.4) 33.37 ± 4.94 (25.3–42.7) 0.729 SL 6.71 ± 1.97 (2.3–10.7) 6.14 ± 1.93 (2-10.4) 0.027 ss; standart deviation, The p values represent the diference between left and right sides The most commonly encountered morphological type of the sphenoid spine on both the right and left sides was quadrangular 35.35% of total, followed by a spine shape. On the left side, the least encountered morphological type of the sphenoid spine was plate-shaped (10.8%), while on the right side, it was cup shaped (12.3%). We found that the tip of the sphenoid spine was bifurcated unilaterally in a total of 3 skulls (4.61%), one with pyramidal and two with quadrangular shaped. Additionally, pterygospinous bar and pterygospinous foramen, formed by the ossification of the pterygopinous ligament, were detected unilaterally on two sides (1.53%). The mentioned variations are shown in Fig. 3 . Morphometric measurement mean values and frequency of sphenoid spine types are given in Table 2 . Table 2 Morphometric parameters in sphenoid spine morphological types Spine Right side Left side n = 15, %23.1 n = 12, 18.5% Quadrangular Right side Left side n = 22, 33.8% n = 24, 36.9% Pyramidal Right side Left side n = 10, 15.4% n = 11, 16.9% Cup Right side Left side n = 11, 16.9% n = 8, 12.3% Plate Right side Left side n = 7, 10.8% n = 10, 15.4% STA 27,91 ± 2,16 27,84 ± 2,08 29,81 ± 2,84 28,9 ± 2,58 29,02 ± 25,5 29,2 ± 2,01 29,4 ± 2,05 28,1 ± 1,92 28,6 ± 3,84 28,1 ± 2,81 SMP 32,6 ± 2,44 32,3 ± 3,41 33,3 ± 3,66 33,8 ± 2,55 32,06 ± 1,6 33,8 ± 2,64 33,38 ± 1,87 35,1 ± 3,85 33,2 ± 3,21 33,4 ± 2,5 SPFl 23,7 ± 3,25 23,09 ± 3,1 24,1 ± 3,23 23,9 ± 2,89 24,3 ± 3,15 24,1 ± 2,68 24,3 ± 2,93 23,4 ± 1,4 22,8 ± 2,31 24,05 ± 26 SPFm 4.97 ± 1.12 4.12 ± 0.8 3.96 ± 0.75 4.01 ± 1.04 4.62 ± 1.2 4.34 ± 0.92 3.92 ± 0.76 4.3 ± 1.11 3.2 ± 0.76 3.5 ± 0.88 SO 29,5 ± 5,59 27,8 ± 3,52 29,9 ± 3,18 30,24 ± 4,2 32,07 ± 4,09 30,13 ± 3,5 29,3 ± 3,04 28,3 ± 3,26 29,1 ± 5,23 31,6 ± 4,31 SCC 6,6 ± 2,17 6,51 ± 2,23 6,57 ± 2,15 6,55 ± 2,47 5,6 ± 1,27 7,81 ± 1,57 7,08 ± 1,66 7,5 ± 2,9 6,68 ± 1,01 5,69 ± 1,68 STS 32,4 ± 3,51 32,36 ± 3,9 33,2 ± 3,36 33,5 ± 2,63 34,8 ± 2,31 35,38 ± 2,7 32,9 ± 3,14 33,31 ± 4,11 32,1 ± 6,02 31,89 ± 10 SL 6,8 ± 2,45 6,37 ± 1,63 6,7 ± 2,05 5,66 ± 1,85 7,18 ± 0,94 5,09 ± 1,13 6,67 ± 1,65 4,87 ± 195 5,98 ± 2,39 5,4 ± 2,01 As shown in Table 3 , it was determined that the foramen spinosum is frequently located in the anteromedial aspect of the sphenoid spine on both sides. It can be said that the foramen spinosum is frequently located anteromedially in skulls with spine, quadrangular, and pyramidal shapes of sphenoid spine while in plate shape, lateralization of the foramen spinosum is more commonly observed. According to the Chi-square test result, the localization of the foramen spinosum was associated with the morphological type of the sphenoid spine on both sides. Table 3 Foramen spinosum localisation according to sphenoid spine morphology A Right Left %4.6 %4.6 M Right Left %9.2 %9.2 L Right Left %6.2 %6.2 MO Right Left %4.6 %1.5 AM Right Left %33.8%38.5 AO Right Left %33.8 %26.2 AL Right Left %7.7 %10.8 LO Right Left - %3.1 p Spine 1 0 1 1 0 0 2 1 5 6 6 3 0 0 0 1 0.012* 0.016** Quadrangular 0 3 1 1 0 2 1 0 10 9 9 8 1 0 0 1 Pyramidal 1 0 1 1 0 0 0 0 5 6 2 4 1 0 0 0 Cup 1 0 3 2 2 0 0 0 2 3 3 1 0 2 0 0 Plate 0 0 0 1 2 2 0 0 0 1 2 1 3 5 0 0 The Pearson Chi square p values represent the location of the foramen spinosum is related to the type of sphenoid spine on the right* and left** sides Discussion The safe exposure of the parapharyngeal segment of the ICA is necessary for many surgical procedures that will be performed through the infratemporal fossa. In addition to the sphenoid spine being an important anatomical landmark for identifying the internal carotid artery, its relationship with the position of the foramen spinosum is also clinically important. However, its anatomical variations and relationship with other structures in the infratemporal fossa have not been precisely elucidated [ 7 ]. In this study, we examined the anatomical variations of the sphenoid spine and morphometrically evaluated its relationship with important structures and bony landmarks on 65 skulls. We did not find statistical difference between the right and left sides in SMP and STA values similar to Infant Reshawn et al. [ 4 ]. They reported SMP values in 30 skulls as 30.56 ± 1.10 mm and 30.66 ± 1.12 mm, STA values as 22.07 ± 2.12 mm and 22.13 ± 2.12 mm, on the right and left sides, respectively. While the SMP values in our study are close to their findings, our STA values are higher. Liu et al. [ 10 ] defined the intersection point of the sphenosquamous suture with the infratemporal crest as ' point O' and reported that point O can be used as a reliable landmark in lateral skull base surgeries when other landmark points cannot be identified. Our distance values between the sphenoid spine and O point were not statistically different between the right and left sides, however, were found to be distributed in a wide range, 21.3 mm-40.4 mm and 20.7 mm-39.9 mm, respectively. Another surgical reference point used in infratemporal fossa surgeries is a bony prominence located at the anterior end of the infratemporal crest, referred to as the sphenoidal tubercle in the literature. It is confused with the sphenoid spine in some studies [ 11 , 15 ]. It has been reported that the sphenoidal tubercle was found to be giant bony prominence in a case and it may pose an obstacle to surgical access to the skull base [ 11 ]. In this study, we did not identify any remarkable morphology in the sphenoidal tubercle, and the mean STS values on the right and left sides were found to be quite close to each other. The lateral pterygoid muscle, the only muscle responsible for opening the jaw, attaches to the sphenoidal tubercle, and the sphenomandibular ligament, extending between the sphenoid spine and mandibular lingula, is tense when the jaw is open [ 12 ]. Therefore, the anatomy of the sphenoid spine and sphenoidal tubercle may be related. Furthermore, it is reported that there is a close relationship between the temporomandibular joint and middle ear explained by the presence of the discomalleolar ligament, anterior mallear ligament and the sphenomandibulare ligament. It is considered that the presence of otological symptoms in patients with temporomandibular joint disorders may be associated with the petrotympanic fissure morphology and ossification. Also, the increased presence of the foramen of Huschke with age, which is a causes of otological symptoms, is explained by the weakening of bone tissue by mastication forces [ 1 , 9 ]. In the present study, we did not find difference for SPFm and SPFl between the right and left sides. As seen in Table 2 , the SPFm distance was the lowest in plate shaped sphenoid spines. Considering the frequent lateral placement of the foramen spinosum in these shapes, it can be said that, as mentioned by Sugano et al. [ 16 ], the foramen spinosum is very close to the petrotympanic fissure in these skulls. Li et al. [ 7 ] reported that the distance from the sphenoid spine to the external orifice of the carotid canal, from 2.5 to 6.1 mm was highly variable. Although our data are variable similar to their findings, ranged from 2.2 to 11.1 and 2.4 to 12.4 on the right and left sides, respectively, reveal a significantly higher maximum value. Our SCC findings are closer to the values reported by Sink et al. [ 13 ] as 8.02 ± 1.35 mm (5.13 mm–13.60 mm) and 8.22 ± 1.47 mm (5.04 mm–14.97 mm) on the right and left sides, respectively. Li et al. [ 7 ] reported that sphenoid spine length was also variable. We found that only the sphenoid spine length was statistically different between the right and left sides and our mean values are close to their finding of 5.98 mm. They reported that the tip of the sphenoid spine bifurcated in 10% of the specimens, which is higher than the rate of 3.07% we identified. However, they used only 10 skulls. Iwagana et al. [ 5 ], detected bony pterygospinosus bar on two sides (%6.66) in 15 cadaveric head specimens which was higher than our study (Fig. 3 ). They found that the presence of a pterygospinous bar affected the course of the mandibular nerve branches, and in one case, the middle meningeal artery traversing the pterygospinosus bar. In the literature, only Infant Reshawn et al. [ 4 ] categorized sphenoid spine morphology as sharp, rounded, blunt, and pointed in 30 skulls. However, they did not provide detailed information or examples related to this morphological classification in their reports. We classified sphenoid spine types into 5 categories, as seen in Fig. 1 . Infant Reshawn et al. (2020) most commonly identified a rounded shape. Interestingly, we found that the sphenoid spine, which we know as a spiny protrusion, was often quadrangular shape not spiny. In our study, a significant association were found between the morphological shape of the sphenoid spine and the location of the foramen spinosum on both sides. Worku et al. [ 17 ] and Sophia et al. [ 14 ] classified the position of the foramen spinosum according to the sphenoid spine as normal (anteromedial), lateral, and medial placements. Worku et al. [ 17 ] found that the foramen spinosum anteromedially located in 61 of a total of 64 skulls. Sophia et al. [ 14 ] reported that the rate of anteromedial location of the foramen spinosum as 25% in 40 skulls on 80 sides. The total anteromedial placement percentage of our study is 36.15%, lower than Worku et al. [ 17 ] and higher than Sophia et al. [ 14 ]. Worku et al. [ 17 ] reported lateral and medial placement on 4 and 2 sides, respectively. Sophia et al. [ 14 ] reported the highest lateral placement on 21 sides, medial placement on three sides. Sugano et al. [ 16 ] detected laterally located foramen spinosum on 2 sides in 30 skulls. In this study, we classified the position of the foramen spinosum relation to sphenoid spine in more detail, as merely classifying it as lateral and medial did not provide an assessment in the anteroposterior direction, as in its normal anatomical position. Sink et al.'s [ 13 ] classification of foramen spinosum localisation is similar to our study, but they did not evaluate the middle meningeal artery groove. They found posterolateral (%3.5), posteromedial (%0.39), and posteriorly (%0.78) located foramen spinosum, but we did not identify any in our skulls. While their percentages of anteromedial (%48.64), anterolateral (%20.3) and anteriorly (%14.79) located foramen spinosum are higher than our study, the lateral placement value is close to our findings (%5.84). Conclusion Our findings provide detailed information about the shape of the sphenoid spine, its relationship with other anatomical structures surrounding the skull base, and the localization of the foramen spinosum. Variations in anatomical structures and their relationships with each other should be considered in the evaluation of pathologies in the middle cranial fossa and in the planning of surgical interventions for this region. Declarations Author contribution ED Ipek: Project development, Conceptualization, Data collection and analysis, Manuscript writing, Manuscript review and editing, Supervision. B Ozustun: Data collection and analysis. I Akdogan: Manuscript review and editing, Supervision. All authors approved the final version of the manuscript. Conflict of interest The authors declare that they have no competing interest. Funding The authors received no financial support the research, authorship, and/or publication of this article. References Almășan O, Leucuța DC, Dinu C, Buduru S, Băciuț M, Hedeșiu M (2022) Petrotympanic Fissure Architecture and Malleus Location in Temporomandibular Joint Disorders. Tomography 8(5):2460–2470. https://doi.org/10.3390/tomography8050204 Falcon RT, Rivera-Serrano CM, Miranda JF, Prevedello DM, Snyderman CH, Kassam AB, Carrau RL (2011) Endoscopic endonasal dissection of the infratemporal fossa: anatomic relationships and importance of eustachian tube in the endoscopic skull base surgery. 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PeerJ 11:e16559. https://doi.org/10.7717/peerj.16559 Sophia MM, Kalpana R (2015) A study on foramen spinosum. Int J Health Sci Res 5(2):187–193 Stajčić LS, Gačić B, Popović N, Stajčić Z (2010) Anatomical study of the pterygopalatine fossa pertinent to the maxillary nerve block at the foramen rotundum. Int J Oral Maxillofac Surg 39(5):493–496. https://doi.org/10.1016/j.ijom.2009.11.002 Sugano GT, Pauris CC, Silva YBE, Pandini FE, Palermo RBS, Buchaim DV, Chacon EL, Castro CA, Pagani BT, Cunha MRD (2022) Topographic and Morphometric Study of the Foramen Spinosum of the Skull and Its Clinical Correlation. Medicina 58(12):1740. https://doi.org/10.3390/medicina58121740 Worku MG, Clarke E (2021) Morphometric analysis of the foramen spinosum and variations of its shape, number, and relation to the spine of the sphenoid bone. Translational Res Anat 24:100124. https://doi.org/10.1016/j.tria.2021.100124 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3867864","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":267837195,"identity":"b52965a4-ba16-4495-aace-7d750b9a2719","order_by":0,"name":"Eda Duygu Ipek","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA4ElEQVRIiWNgGAWjYFCCBDDBw8DewCABZDE2EK+F5wBMCzNxWhgYJBKI1MLPnvyA4UdNmoz5zMcPb/Mw2MhuOMB/7AM+LZI9zwwYe47l8MjcTjO25mFIM95wgJl5Bj4tBjcSDJgZ2Cp4JKQTzKR5GA4ngrTgdZj9jfQPzAz/gFokj38DavlPWIuBRI4BM2NbDo+EBA/IlgOEtUiceVNwsLcvjUeCJ6fYco5BsvHMw8zGeLXwt6dvfPDjW7K9BPvxjTfeVNjJ9h1vfIxXCwgcQHInEBOMyVEwCkbBKBgFBAEAajRBqpVZAPkAAAAASUVORK5CYII=","orcid":"","institution":"Aydın Adnan Menderes Üniversitesi Uygulama ve Araştırma Hastanesi","correspondingAuthor":true,"prefix":"","firstName":"Eda","middleName":"Duygu","lastName":"Ipek","suffix":""},{"id":267837196,"identity":"5a044c0a-738e-4ee0-ae10-f3a830f188b5","order_by":1,"name":"Berrin Ozustun","email":"","orcid":"","institution":"Aydın Adnan Menderes Üniversitesi Uygulama ve Araştırma Hastanesi","correspondingAuthor":false,"prefix":"","firstName":"Berrin","middleName":"","lastName":"Ozustun","suffix":""},{"id":267837197,"identity":"9a26e1f9-0691-4c9a-b234-9111ea96e013","order_by":2,"name":"Ilgaz Akdogan","email":"","orcid":"","institution":"Aydın Adnan Menderes Üniversitesi Uygulama ve Araştırma Hastanesi","correspondingAuthor":false,"prefix":"","firstName":"Ilgaz","middleName":"","lastName":"Akdogan","suffix":""}],"badges":[],"createdAt":"2024-01-15 22:14:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3867864/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3867864/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":49991437,"identity":"6c0d29c9-9ee3-45a8-8bb5-4d3e0977e4e0","added_by":"auto","created_at":"2024-01-22 18:46:59","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":2115651,"visible":true,"origin":"","legend":"\u003cp\u003eExamples of sphenoid spine morphological types\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-3867864/v1/5a45431964a68606e6b787fd.png"},{"id":49991435,"identity":"4fc709af-15f7-42bc-a163-5df326b62462","added_by":"auto","created_at":"2024-01-22 18:46:59","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2123160,"visible":true,"origin":"","legend":"\u003cp\u003eThe foramen spinosum localization relation to the sphenoid spine. The black arrows show the middle meningeal artery groove observed at the root of the sphenoid spine\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-3867864/v1/eab42cddf0893e01f703b1d6.png"},{"id":49991436,"identity":"f6f52bdb-ca25-4405-a4ca-0a91506efa7d","added_by":"auto","created_at":"2024-01-22 18:46:59","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":649466,"visible":true,"origin":"","legend":"\u003cp\u003eA; Bifurcated sphenoid spine, B; White arrow indicates pterygospinosus foramen (Civinini’s foramen)\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-3867864/v1/e9bd4afa9607194bf6139f1c.png"},{"id":52311564,"identity":"a67af2b4-5bb4-4c7c-959e-1f42a29c24e6","added_by":"auto","created_at":"2024-03-08 21:41:25","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4477578,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3867864/v1/a9402fc7-afca-4077-b573-b1773c1e26b3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Investigation of Sphenoid Spine Morphometry for Skull Base Surgery and Relation to Foramen Spinosum Localization","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe sphenoid spine, described as spina ossis sphenoidalis in anatomy terminology, is a pointed protrusion extending downward from the junction of the squamosal and posterior borders of the greater wings of the sphenoid bone. Three ligaments, ligamentum sphenomandibulare, mallei anterius and pterygospinosus, two muscles, musculus tensor veli palatini and tensor tympani, are attached to the sphenoid spine. Furthermore, it is adjacent to the cartilaginous part of the external auditory canal and chorda tympani medially and to the auriculotemporal nerve laterally [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTechnological advancements have significantly expanded the range of areas accessible through endoscopic approaches in skull base surgeries, but the complications attributed to these approaches have also increased proportionally [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. The internal carotid artery (ICA) is the most feared structure by endoscopic surgeons for its complications in skull base surgeries. In particular, there is a lack of anatomical landmarks that allow the safe exposure of the cervical portion of the ICA, which is surrounded by soft tissues throughout the parapharyngeal area in infratemporal fossa and access to this segment of the ICA is less defined [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In endoscopic transpterygoid approach, the pterygoid plate, mandibular nerve, Eustachian tube, and styloid process have been reported as reliable landmarks for reaching the parapharyngeal ICA [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Liu et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] reported that the sphenoid spine and foramen spinosum are anatomical landmarks for the cartilaginous and bony junction of the Eustachian tube, and parapharyngeal ICA was located immediately posteroinferior to the sphenoid spine. Li et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] also found that the sphenoid spine, tympanic crest, vaginal process of tympanic bone were the closest anatomical landmarks to the parapharyngeal ICA in the endoscopic transmasticator approach. Li et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] reported that in transoral nasopharyngectomy, it is mandatory to define the parapharyngeal ICA before transection of the Eustachian tube and the best landmarks definining it are the sphenoid spine, petrotympanic fissure and pterigoid hamulus.\u003c/p\u003e \u003cp\u003eThe foramen spinosum, in which the middle meningeal vessels and the meningeal branch of mandibular nerve pass through it to middle cranial fossa, is located in the greater wing of the sphenoid bone. It is named \u0026lsquo;spinosum\u0026rsquo; due to its close proximity to sphenoid spine and is described in classical anatomy texts to be located on the anteromedial side of sphenoid spine [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Although it has been evaluated in very few studies in the literature and in its normal position (anteromedial), lateral and medial placements mostly, it is observed that the localization of foramen spinosum varies relation to the sphenoid spine [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The localization of the foramen spinosum is important in various procedures, such as endovascular embolization of dural arteriovenous fistulas and meningiomas through the middle meningeal artery [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], in bypass operations where middle meningeal artery is used as a graft [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Also, it has been reported that anatomical variations of the foramen spinosum may be associated with abnormal development of the middle meningeal artery [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Therefore, a more detailed understanding of the localization of the foramen spinosum is necessary in the preoperative assessment of possible changes in the trajectory of neurovascular structures. Sphenoid spine used as a landmark during infratemporal surgical approaches due to its close proximity to the foramen spinosum, parapharyngeal ICA, Eustachian tube and chorda tympani [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Despite its clinical importance, there is a lack of data in the literature regarding the anatomical variations of the sphenoid spine, and studies investigating its relationship with adjacent structures are insufficient. In the present study, considering the importance of the topography of sphenoid spine and foramen spinosum in skull base surgeries, it was aimed to examine more detail of the foramen spinosum localization relation to the sphenoid spine and morphometric analysis of sphenoid spine with related structures.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003eIn this study, 65 adult skulls of unknown gender, obtained from the bone archive of Aydin Adnan Menderes University, Faculty of Medicine, Department of Anatomy, were used. Damaged skulls that did not allow examination of the targeted structures were not included in the study. The distance of the sphenoid spine to the tip of mastoid process (SMP), to the tip of tuberculum articulare (STA), to the anterior border of external orifice of the carotid canal (SCC), to the point where the sutura sphenosquamosa intersects the crista infratemporalis (SO), to the most lateral (SPFl) and medial (SPFm) endpoints of the petrotympanic fissure, to the sphenoidal tubercle (STS), and the length of the sphenoid spine (SL) were measured on the right and left sides, using a digital Vernier caliper with a precision of 0.01 mm.\u003c/p\u003e \u003cp\u003eThe morphological characterization of the sphenoid spine was classified into five types: spine, quadrangular, pyramidal, plate and cup shaped, as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The localization of the foramen spinosum relation to the sphenoid spine was examined from the basis cranii externa. A sagittal line was passed through the center of the foramen spinosum as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The location of the foramen spinosum was classified as medial (M), lateral (L), anterior (A), anteromedial (AM), anterolateral (AL) and anterior-on the line (AO), medial-on the line (MO) and lateral-on the line (LO). In M and L placement, the sagittal line passed through the medial and lateral sides of the sphenoid spine while intersected with the sphenoid spine in A placement. In the AM and AL placement, the foramen spinosum was in front of the sphenoid spine and the sagittal line was on the medial and lateral sides of the sphenoid spine, respectively. Skulls with a line transition similar to the M, L and A placement of the foramen spinosum, but where the middle meningeal artery groove was observed on the sphenoid spine root, were classified as MO, LO and AO, respectively.\u003c/p\u003e \u003cp\u003eSPSS (Version 22.0, SPSS Inc., Chicago, IL, USA) program was used for statistical analysis of the data. The distribution pattern of the data was evaluated with the Kolmogorov Smirnov test and paired-t test was applied to compare the right and left morphometric parameters. Chi-square test was used to evaluate the localization of the foramen spinosum according to sphenoid spine morphological types.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe descriptive statistics of the morphometric measurements we conducted are indicated in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. In comparing the morphometric measurements between the right and left sides, it was found that only the length of the sphenoid spine was statistically higher on the right side (p\u0026thinsp;=\u0026thinsp;0.027).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean, minimum and maximum values of morphometric parameters\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRight side\u003c/p\u003e \u003cp\u003emean\u0026thinsp;\u0026plusmn;\u0026thinsp;ss (min\u0026ndash;max)\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;65\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLeft side\u003c/p\u003e \u003cp\u003emean\u0026thinsp;\u0026plusmn;\u0026thinsp;ss (min\u0026ndash;max)\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;65\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003cp\u003e(Sig. 2-tailed)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSTA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e29.08\u0026thinsp;\u0026plusmn;\u0026thinsp;2.67 (22.7\u0026ndash;35.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e28.57\u0026thinsp;\u0026plusmn;\u0026thinsp;2.36 (22.1\u0026ndash;34.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.71\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSMP\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e32.97\u0026thinsp;\u0026plusmn;\u0026thinsp;2.79 (26.6\u0026ndash;44,1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e33.67\u0026thinsp;\u0026plusmn;\u0026thinsp;2.93 (25.8\u0026ndash;41.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.63\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPFl\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e23.98\u0026thinsp;\u0026plusmn;\u0026thinsp;3.03 (17.5\u0026ndash;30.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e23.79\u0026thinsp;\u0026plusmn;\u0026thinsp;2.68 (18-29.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.602\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPFm\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e4.05\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27 (2.2\u0026ndash;5.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.21\u0026thinsp;\u0026plusmn;\u0026thinsp;1.27 (2.1\u0026ndash;6.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.512\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSO\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e29.98\u0026thinsp;\u0026plusmn;\u0026thinsp;4.17 (21.3\u0026ndash;40.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e29.76\u0026thinsp;\u0026plusmn;\u0026thinsp;4.01 (20.7\u0026ndash;39.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.635\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSCC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e6.53\u0026thinsp;\u0026plusmn;\u0026thinsp;1.86 (2.2\u0026ndash;11.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6.74\u0026thinsp;\u0026plusmn;\u0026thinsp;2.28 (2.4\u0026ndash;12.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.426\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSTS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e33.13\u0026thinsp;\u0026plusmn;\u0026thinsp;3.57 (20.5\u0026ndash;41.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e33.37\u0026thinsp;\u0026plusmn;\u0026thinsp;4.94 (25.3\u0026ndash;42.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.729\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSL\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e6.71\u0026thinsp;\u0026plusmn;\u0026thinsp;1.97 (2.3\u0026ndash;10.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6.14\u0026thinsp;\u0026plusmn;\u0026thinsp;1.93 (2-10.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e0.027\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003ess; standart deviation, The p values represent the diference between left and right sides\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eThe most commonly encountered morphological type of the sphenoid spine on both the right and left sides was quadrangular 35.35% of total, followed by a spine shape. On the left side, the least encountered morphological type of the sphenoid spine was plate-shaped (10.8%), while on the right side, it was cup shaped (12.3%). We found that the tip of the sphenoid spine was bifurcated unilaterally in a total of 3 skulls (4.61%), one with pyramidal and two with quadrangular shaped. Additionally, pterygospinous bar and pterygospinous foramen, formed by the ossification of the pterygopinous ligament, were detected unilaterally on two sides (1.53%). The mentioned variations are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Morphometric measurement mean values and frequency of sphenoid spine types are given in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMorphometric parameters in sphenoid spine morphological types\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"11\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eSpine\u003c/p\u003e \u003cp\u003eRight side Left side\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;15, %23.1 n\u0026thinsp;=\u0026thinsp;12, 18.5%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eQuadrangular\u003c/p\u003e \u003cp\u003eRight side Left side\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;22, 33.8% n\u0026thinsp;=\u0026thinsp;24, 36.9%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003ePyramidal\u003c/p\u003e \u003cp\u003eRight side Left side\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;10, 15.4% n\u0026thinsp;=\u0026thinsp;11, 16.9%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eCup\u003c/p\u003e \u003cp\u003eRight side Left side\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;11, 16.9% n\u0026thinsp;=\u0026thinsp;8, 12.3%\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003ePlate\u003c/p\u003e \u003cp\u003eRight side Left side\u003c/p\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;7, 10.8% n\u0026thinsp;=\u0026thinsp;10, 15.4%\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSTA\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e27,91\u0026thinsp;\u0026plusmn;\u0026thinsp;2,16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e27,84\u0026thinsp;\u0026plusmn;\u0026thinsp;2,08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e29,81\u0026thinsp;\u0026plusmn;\u0026thinsp;2,84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e28,9\u0026thinsp;\u0026plusmn;\u0026thinsp;2,58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e29,02\u0026thinsp;\u0026plusmn;\u0026thinsp;25,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e29,2\u0026thinsp;\u0026plusmn;\u0026thinsp;2,01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e29,4\u0026thinsp;\u0026plusmn;\u0026thinsp;2,05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e28,1\u0026thinsp;\u0026plusmn;\u0026thinsp;1,92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e28,6\u0026thinsp;\u0026plusmn;\u0026thinsp;3,84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e28,1\u0026thinsp;\u0026plusmn;\u0026thinsp;2,81\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSMP\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e32,6\u0026thinsp;\u0026plusmn;\u0026thinsp;2,44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e32,3\u0026thinsp;\u0026plusmn;\u0026thinsp;3,41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e33,3\u0026thinsp;\u0026plusmn;\u0026thinsp;3,66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e33,8\u0026thinsp;\u0026plusmn;\u0026thinsp;2,55\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e32,06\u0026thinsp;\u0026plusmn;\u0026thinsp;1,6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e33,8\u0026thinsp;\u0026plusmn;\u0026thinsp;2,64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e33,38\u0026thinsp;\u0026plusmn;\u0026thinsp;1,87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e35,1\u0026thinsp;\u0026plusmn;\u0026thinsp;3,85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e33,2\u0026thinsp;\u0026plusmn;\u0026thinsp;3,21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e33,4\u0026thinsp;\u0026plusmn;\u0026thinsp;2,5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPFl\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e23,7\u0026thinsp;\u0026plusmn;\u0026thinsp;3,25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e23,09\u0026thinsp;\u0026plusmn;\u0026thinsp;3,1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e24,1\u0026thinsp;\u0026plusmn;\u0026thinsp;3,23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e23,9\u0026thinsp;\u0026plusmn;\u0026thinsp;2,89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e24,3\u0026thinsp;\u0026plusmn;\u0026thinsp;3,15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e24,1\u0026thinsp;\u0026plusmn;\u0026thinsp;2,68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e24,3\u0026thinsp;\u0026plusmn;\u0026thinsp;2,93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e23,4\u0026thinsp;\u0026plusmn;\u0026thinsp;1,4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e22,8\u0026thinsp;\u0026plusmn;\u0026thinsp;2,31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e24,05\u0026thinsp;\u0026plusmn;\u0026thinsp;26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSPFm\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e4.97\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e4.12\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e3.96\u0026thinsp;\u0026plusmn;\u0026thinsp;0.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e4.01\u0026thinsp;\u0026plusmn;\u0026thinsp;1.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e4.62\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e4.34\u0026thinsp;\u0026plusmn;\u0026thinsp;0.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e3.92\u0026thinsp;\u0026plusmn;\u0026thinsp;0.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e3.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e3.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.88\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSO\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e29,5\u0026thinsp;\u0026plusmn;\u0026thinsp;5,59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e27,8\u0026thinsp;\u0026plusmn;\u0026thinsp;3,52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e29,9\u0026thinsp;\u0026plusmn;\u0026thinsp;3,18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e30,24\u0026thinsp;\u0026plusmn;\u0026thinsp;4,2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e32,07\u0026thinsp;\u0026plusmn;\u0026thinsp;4,09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e30,13\u0026thinsp;\u0026plusmn;\u0026thinsp;3,5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e29,3\u0026thinsp;\u0026plusmn;\u0026thinsp;3,04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e28,3\u0026thinsp;\u0026plusmn;\u0026thinsp;3,26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e29,1\u0026thinsp;\u0026plusmn;\u0026thinsp;5,23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e31,6\u0026thinsp;\u0026plusmn;\u0026thinsp;4,31\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSCC\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e6,6\u0026thinsp;\u0026plusmn;\u0026thinsp;2,17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6,51\u0026thinsp;\u0026plusmn;\u0026thinsp;2,23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e6,57\u0026thinsp;\u0026plusmn;\u0026thinsp;2,15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e6,55\u0026thinsp;\u0026plusmn;\u0026thinsp;2,47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e5,6\u0026thinsp;\u0026plusmn;\u0026thinsp;1,27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e7,81\u0026thinsp;\u0026plusmn;\u0026thinsp;1,57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e7,08\u0026thinsp;\u0026plusmn;\u0026thinsp;1,66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e7,5\u0026thinsp;\u0026plusmn;\u0026thinsp;2,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e6,68\u0026thinsp;\u0026plusmn;\u0026thinsp;1,01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e5,69\u0026thinsp;\u0026plusmn;\u0026thinsp;1,68\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSTS\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e32,4\u0026thinsp;\u0026plusmn;\u0026thinsp;3,51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e32,36\u0026thinsp;\u0026plusmn;\u0026thinsp;3,9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e33,2\u0026thinsp;\u0026plusmn;\u0026thinsp;3,36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e33,5\u0026thinsp;\u0026plusmn;\u0026thinsp;2,63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e34,8\u0026thinsp;\u0026plusmn;\u0026thinsp;2,31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e35,38\u0026thinsp;\u0026plusmn;\u0026thinsp;2,7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e32,9\u0026thinsp;\u0026plusmn;\u0026thinsp;3,14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e33,31\u0026thinsp;\u0026plusmn;\u0026thinsp;4,11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e32,1\u0026thinsp;\u0026plusmn;\u0026thinsp;6,02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e31,89\u0026thinsp;\u0026plusmn;\u0026thinsp;10\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSL\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e6,8\u0026thinsp;\u0026plusmn;\u0026thinsp;2,45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e6,37\u0026thinsp;\u0026plusmn;\u0026thinsp;1,63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e6,7\u0026thinsp;\u0026plusmn;\u0026thinsp;2,05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e5,66\u0026thinsp;\u0026plusmn;\u0026thinsp;1,85\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c6\"\u003e \u003cp\u003e7,18\u0026thinsp;\u0026plusmn;\u0026thinsp;0,94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c7\"\u003e \u003cp\u003e5,09\u0026thinsp;\u0026plusmn;\u0026thinsp;1,13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c8\"\u003e \u003cp\u003e6,67\u0026thinsp;\u0026plusmn;\u0026thinsp;1,65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c9\"\u003e \u003cp\u003e4,87\u0026thinsp;\u0026plusmn;\u0026thinsp;195\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c10\"\u003e \u003cp\u003e5,98\u0026thinsp;\u0026plusmn;\u0026thinsp;2,39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c11\"\u003e \u003cp\u003e5,4\u0026thinsp;\u0026plusmn;\u0026thinsp;2,01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAs shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, it was determined that the foramen spinosum is frequently located in the anteromedial aspect of the sphenoid spine on both sides. It can be said that the foramen spinosum is frequently located anteromedially in skulls with spine, quadrangular, and pyramidal shapes of sphenoid spine while in plate shape, lateralization of the foramen spinosum is more commonly observed. According to the Chi-square test result, the localization of the foramen spinosum was associated with the morphological type of the sphenoid spine on both sides.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eForamen spinosum localisation according to sphenoid spine morphology\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"18\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c14\" colnum=\"14\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c15\" colnum=\"15\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c16\" colnum=\"16\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c17\" colnum=\"17\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c18\" colnum=\"18\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eA\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e%4.6 %4.6\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c5\" namest=\"c4\"\u003e \u003cp\u003eM\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e%9.2 %9.2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c7\" namest=\"c6\"\u003e \u003cp\u003eL\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e%6.2 %6.2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eMO\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e%4.6 %1.5\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c11\" namest=\"c10\"\u003e \u003cp\u003eAM\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e%33.8%38.5\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c13\" namest=\"c12\"\u003e \u003cp\u003eAO\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e%33.8 %26.2\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c15\" namest=\"c14\"\u003e \u003cp\u003eAL\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e%7.7 %10.8\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c17\" namest=\"c16\"\u003e \u003cp\u003eLO\u003c/p\u003e \u003cp\u003eRight Left\u003c/p\u003e \u003cp\u003e- %3.1\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c18\"\u003e \u003cp\u003ep\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSpine\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c15\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c17\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c18\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e\u003cb\u003e0.012*\u003c/b\u003e\u003c/p\u003e \u003cp\u003e\u003cb\u003e0.016**\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eQuadrangular\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c15\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c17\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePyramidal\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c15\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c17\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eCup\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c15\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c17\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003ePlate\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c15\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c16\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c17\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"18\"\u003eThe Pearson Chi square p values represent the location of the foramen spinosum is related to the type of sphenoid spine on the right* and left** sides\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe safe exposure of the parapharyngeal segment of the ICA is necessary for many surgical procedures that will be performed through the infratemporal fossa. In addition to the sphenoid spine being an important anatomical landmark for identifying the internal carotid artery, its relationship with the position of the foramen spinosum is also clinically important. However, its anatomical variations and relationship with other structures in the infratemporal fossa have not been precisely elucidated [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this study, we examined the anatomical variations of the sphenoid spine and morphometrically evaluated its relationship with important structures and bony landmarks on 65 skulls. We did not find statistical difference between the right and left sides in SMP and STA values similar to Infant Reshawn et al. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. They reported SMP values in 30 skulls as 30.56\u0026thinsp;\u0026plusmn;\u0026thinsp;1.10 mm and 30.66\u0026thinsp;\u0026plusmn;\u0026thinsp;1.12 mm, STA values as 22.07\u0026thinsp;\u0026plusmn;\u0026thinsp;2.12 mm and 22.13\u0026thinsp;\u0026plusmn;\u0026thinsp;2.12 mm, on the right and left sides, respectively. While the SMP values in our study are close to their findings, our STA values are higher. Liu et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] defined the intersection point of the sphenosquamous suture with the infratemporal crest as ' point O' and reported that point O can be used as a reliable landmark in lateral skull base surgeries when other landmark points cannot be identified. Our distance values between the sphenoid spine and O point were not statistically different between the right and left sides, however, were found to be distributed in a wide range, 21.3 mm-40.4 mm and 20.7 mm-39.9 mm, respectively. Another surgical reference point used in infratemporal fossa surgeries is a bony prominence located at the anterior end of the infratemporal crest, referred to as the sphenoidal tubercle in the literature. It is confused with the sphenoid spine in some studies [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. It has been reported that the sphenoidal tubercle was found to be giant bony prominence in a case and it may pose an obstacle to surgical access to the skull base [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In this study, we did not identify any remarkable morphology in the sphenoidal tubercle, and the mean STS values on the right and left sides were found to be quite close to each other. The lateral pterygoid muscle, the only muscle responsible for opening the jaw, attaches to the sphenoidal tubercle, and the sphenomandibular ligament, extending between the sphenoid spine and mandibular lingula, is tense when the jaw is open [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Therefore, the anatomy of the sphenoid spine and sphenoidal tubercle may be related.\u003c/p\u003e \u003cp\u003eFurthermore, it is reported that there is a close relationship between the temporomandibular joint and middle ear explained by the presence of the discomalleolar ligament, anterior mallear ligament and the sphenomandibulare ligament. It is considered that the presence of otological symptoms in patients with temporomandibular joint disorders may be associated with the petrotympanic fissure morphology and ossification. Also, the increased presence of the foramen of Huschke with age, which is a causes of otological symptoms, is explained by the weakening of bone tissue by mastication forces [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In the present study, we did not find difference for SPFm and SPFl between the right and left sides. As seen in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, the SPFm distance was the lowest in plate shaped sphenoid spines. Considering the frequent lateral placement of the foramen spinosum in these shapes, it can be said that, as mentioned by Sugano et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], the foramen spinosum is very close to the petrotympanic fissure in these skulls. Li et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] reported that the distance from the sphenoid spine to the external orifice of the carotid canal, from 2.5 to 6.1 mm was highly variable. Although our data are variable similar to their findings, ranged from 2.2 to 11.1 and 2.4 to 12.4 on the right and left sides, respectively, reveal a significantly higher maximum value. Our SCC findings are closer to the values reported by Sink et al. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] as 8.02\u0026thinsp;\u0026plusmn;\u0026thinsp;1.35 mm (5.13 mm\u0026ndash;13.60 mm) and 8.22\u0026thinsp;\u0026plusmn;\u0026thinsp;1.47 mm (5.04 mm\u0026ndash;14.97 mm) on the right and left sides, respectively. Li et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] reported that sphenoid spine length was also variable. We found that only the sphenoid spine length was statistically different between the right and left sides and our mean values are close to their finding of 5.98 mm. They reported that the tip of the sphenoid spine bifurcated in 10% of the specimens, which is higher than the rate of 3.07% we identified. However, they used only 10 skulls. Iwagana et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], detected bony pterygospinosus bar on two sides (%6.66) in 15 cadaveric head specimens which was higher than our study (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). They found that the presence of a pterygospinous bar affected the course of the mandibular nerve branches, and in one case, the middle meningeal artery traversing the pterygospinosus bar.\u003c/p\u003e \u003cp\u003eIn the literature, only Infant Reshawn et al. [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] categorized sphenoid spine morphology as sharp, rounded, blunt, and pointed in 30 skulls. However, they did not provide detailed information or examples related to this morphological classification in their reports. We classified sphenoid spine types into 5 categories, as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Infant Reshawn et al. (2020) most commonly identified a rounded shape. Interestingly, we found that the sphenoid spine, which we know as a spiny protrusion, was often quadrangular shape not spiny. In our study, a significant association were found between the morphological shape of the sphenoid spine and the location of the foramen spinosum on both sides. Worku et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] and Sophia et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] classified the position of the foramen spinosum according to the sphenoid spine as normal (anteromedial), lateral, and medial placements. Worku et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] found that the foramen spinosum anteromedially located in 61 of a total of 64 skulls. Sophia et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] reported that the rate of anteromedial location of the foramen spinosum as 25% in 40 skulls on 80 sides. The total anteromedial placement percentage of our study is 36.15%, lower than Worku et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] and higher than Sophia et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Worku et al. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] reported lateral and medial placement on 4 and 2 sides, respectively. Sophia et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] reported the highest lateral placement on 21 sides, medial placement on three sides. Sugano et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] detected laterally located foramen spinosum on 2 sides in 30 skulls. In this study, we classified the position of the foramen spinosum relation to sphenoid spine in more detail, as merely classifying it as lateral and medial did not provide an assessment in the anteroposterior direction, as in its normal anatomical position. Sink et al.'s [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] classification of foramen spinosum localisation is similar to our study, but they did not evaluate the middle meningeal artery groove. They found posterolateral (%3.5), posteromedial (%0.39), and posteriorly (%0.78) located foramen spinosum, but we did not identify any in our skulls. While their percentages of anteromedial (%48.64), anterolateral (%20.3) and anteriorly (%14.79) located foramen spinosum are higher than our study, the lateral placement value is close to our findings (%5.84).\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eOur findings provide detailed information about the shape of the sphenoid spine, its relationship with other anatomical structures surrounding the skull base, and the localization of the foramen spinosum. Variations in anatomical structures and their relationships with each other should be considered in the evaluation of pathologies in the middle cranial fossa and in the planning of surgical interventions for this region.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eED Ipek: Project development, Conceptualization, Data collection and analysis, Manuscript writing, Manuscript review and editing, Supervision. B Ozustun: Data collection and analysis. I Akdogan: Manuscript review and editing, Supervision. All authors approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e The authors declare that they have no competing interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e The authors received no financial support the research, authorship, and/or publication of this article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAlmășan O, Leucuța DC, Dinu C, Buduru S, Băciuț M, Hedeșiu M (2022) Petrotympanic Fissure Architecture and Malleus Location in Temporomandibular Joint Disorders. 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Translational Res Anat 24:100124. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.tria.2021.100124\u003c/span\u003e\u003cspan address=\"10.1016/j.tria.2021.100124\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Sphenoid spine, Foramen spinosum, Infratemporal fossa, Endoscopic approach, Skull base","lastPublishedDoi":"10.21203/rs.3.rs-3867864/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3867864/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003eOur study aimed to investigate the sphenoid spine morphological characterization, as well as the distances to important surgical points and its relation to foramen spinosum localization.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eOn a total of 65 skulls, the distances of the sphenoid spine to articular tubercle, mastoid process, external opening of carotid canal, anterior edge of infratemporal crest, and the point where sphenosquamosus suture intersects with infratemporal crest were measured from both the right and left sides. The length of the sphenoid spine was measured and classified morphologically. Localization of foramen spinosum relation to sphenoid spine was evaluated.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe sphenoid spine length was stastistically different which was found to be 6.71\u0026thinsp;\u0026plusmn;\u0026thinsp;1.97 and 6.14\u0026thinsp;\u0026plusmn;\u0026thinsp;1.93 on the rigt and left sides, respectively (p\u0026thinsp;=\u0026thinsp;0.027). The most commonly encountered shape of the sphenoid spine on both sides was rectangular, followed by spine shape. The foramen spinosum was most frequently located anteromedially and least frequently located anterolaterally according to sphenoid spine. In our study, it was determined for the first time that the localization of the foramen spinosum is associated with the shape of the sphenoid spine on both the right (p\u0026thinsp;=\u0026thinsp;0.012) and left (p\u0026thinsp;=\u0026thinsp;0.016) sides.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eOur study provides morphometric data on the sphenoid spine and reports the association between the localization of the foramen spinosum and the type of sphenoid spine. Sphenoid spine variations and their relationship with adjacent anatomical structures should be taken into consideration in middle cranial fossa surgeries.\u003c/p\u003e","manuscriptTitle":"Investigation of Sphenoid Spine Morphometry for Skull Base Surgery and Relation to Foramen Spinosum Localization","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-01-22 18:46:54","doi":"10.21203/rs.3.rs-3867864/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"21668c89-9f0c-4977-a60b-3d3c3872c190","owner":[],"postedDate":"January 22nd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-03-08T21:33:18+00:00","versionOfRecord":[],"versionCreatedAt":"2024-01-22 18:46:54","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3867864","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3867864","identity":"rs-3867864","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}