A three-headed plantaris muscle with a bipartite insertion of its two accessory heads

A three-headed plantaris muscle with a bipartite insertion of its two accessory heads | 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 A three-headed plantaris muscle with a bipartite insertion of its two accessory heads George Triantafyllou, Nicol Zielinska, Maria Piagkou, Krzysztof Koptas, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4369830/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 The plantaris muscle consists of a small muscular and a long tendinous part and is located at the superficial compartment of the posterior leg. The purpose of the current cadaveric report is to describe a rare variant of the plantaris muscle. During a routine dissection, a three-headed plantaris with two accessory heads was identified with a variant insertion of the two accessory heads. All heads originated from the femur popliteal surface, independently the one from the other. The first head contributed to the long and thin calcaneal tendon, and the two accessory heads were mainly inserted via their musculoaponeurotic expansion into the medial femoral condyle. The planatris muscle morphological variability has been extensively studied lately. The incidence of the two-headed muscle has been estimated at 1.6%, while the three-headed muscle corresponds to an even rarer variation. plantaris muscle variation accessory head dissection morphology Figures Figure 1 Figure 2 Introduction The superficial muscle compartment of the posterior leg is composed of the gastrocnemius muscle (GM), the soleus muscle (SM), and the plantaris muscle (PM), which control the foot and ankle plantar flexion. The PM has the most insignificant influence (0.7% of plantar flexor power) [ 13 ]. The PM seems to have a valuable contribution to hand tendon reconstruction and Achilles tendinopathy [ 5 ]. Typically, the PM has a short and slim belly with a long and thin tendon, that originates from the popliteal surface of the femur and the knee joint capsule, and inserts into the calcaneal tuberosity [ 5 ]. Both muscular and tendinous parts demonstrate high morphological variability [ 10 , 11 ]. Rarer PM variants occasionally described were not included in the classifications [ 4 , 9 , 12 , 16 ]. The current cadaveric report describes a three-headed PM, with two accessory heads and an uncommon bipartite insertion of the accessory heads. The morphological variability, as well as possible clinical implications, are further discussed. Case Description A bilateral lower limb dissection for education and research purposes under a pre-established protocol [ 9 ] was performed on an 84-year-old male cadaver, derived from a body donation at the Department of Anatomical Dissection and Donation of the Medical University of Lodz. Skin and subcutaneous fat from the popliteal fossa and posterior leg compartment were dissected to expose the related muscles and neurovascular bundle. The GM lateral and medial heads were carefully identified and then dissected, to expose the SM and PM. On the left limb, an uncommon three-headed PM variant with two accessory heads was identified. The three heads originated independently from the femur popliteal surface. The one head (typical) contributed to the PM's long and thin tendon and was typically inserted into the calcaneal tuberosity. The other two (accessory) heads with their short and thin tendon (per head) had a bipartite insertion into the PM's first head (lateral typical attachment) and the medial femoral condyle (MFC) via their musculoaponeurotic complex expansion (medial variant attachment) (Figs. 1 , 2 ). The contralateral PM was identified as typical. A morphometric analysis of the PM variant was also performed. The measurements were taken twice with up to 0.1 mm accuracy using an electric caliper ( Mitutoyo Corporation, Kawasaki-shi, Kanagawa, Japan ) and are summarized in Table 1 . Table 1 The three-headed plantaris muscle (PM) with two accessory heads (2nd and 3rd ) morphometric measurements, expressed in mm. Morphometric parameters Plantaris muscle (PM) morphology 1st head 2nd head 3rd head Common tendon Length (craniocaudal diameter) 74.24 55.65 50.46 236.62 Width (maximum laterolateral diameter) 7.40 3.70 2.66 - Discussion The current report describes an uncommon three-headed PM with two accessory heads and a bipartite insertion. In the current literature, only two case reports of a three-headed PM have been described, while the identified insertions were not similar to the present case. From a developmental point of view, the three muscles of the superficial compartment of the posterior leg are derivatives of a common pre-muscular mass. The PM’s anlage is located anteriorly to the SM and is partially covered by the GM. In a 12-mm embryo, the PM mass is not differentiated only from GM. Lastly, in a 17-mm embryo, the PM is differentiated from the GM [ 2 ], and differentiation alterations could lead to variant muscle formation. The PM muscular origin has been systematically investigated by Olewnik et al. [ 10 ], and classified into the following six different origin patterns: PM of type I corresponded to a typical origin from the lateral femoral condyle (LFC), the GM lateral head, and the knee joint capsule, in 48.4%. PM of type II corresponded to an origin from the knee joint capsule and the GM lateral head, identified in 25%. PM of type III is characterized by an origin from the LFC, and the knee joint capsule (10.15%). PM of type IV includes an origin from the LFC, the knee joint capsule, and the iliotibial band (6.25%). PM of type V includes an origin from the LFC (8.6%). PM of type VI (2 cases only, 1.6%) were rare PM variants. One variant (0.8%) corresponded to a double PM (two muscular parts and two distinct tendons), and the other variant (0.8%) was characterized as “bifurcated PM” (two muscular parts that fused into a single tendon). Hence, the three-headed PM identified in the current report was not observed in the PM systematic morphological study by Olewnik et al. [ 10 ]. Based on this classification system, Wasniewska et al. [ 15 ] studied the PM in human fetuses and concluded the lack of a bipartite PM, i.e., a duplicated PM (distinct double origins) or bifurcated PM (distinct double insertions). Hence, the duplicated or bifurcated PM corresponds to a rare variant, while the three-headed variant is even rarer. The imaging study by Herzog et al. [ 7 ] is a unique study referring to the accessory PM, based on a review of 1000 magnetic resonance imaging (MRI). The authors identified the PM accessory form in 6.3% (63 cases), reporting a prevalence higher than the cadaveric studies (1.6%). However, it is unclear if the PM muscular part, as well as PM variant forms can be easily visualized via imaging. The existence of PM accessory heads, such as the one described in the present case, has been published before. Olewnik et al. [ 10 ] identified a “double PM” and a “bifurcated PM” in 0.8% of their sample, per each form. During a forensic autopsy, Smedra et al. [ 14 ] observed a PM with two muscular heads that fused to a common tendon, which corresponds to Olewnik et al. [ 10 ] “bifurcated PM”. Futa et al. [ 3 ] observed another morphological variant similar to Smedra et al. [ 14 ]. Contrariwise, Kurtys, and co-authors [ 8 ] and Heo et al. [ 6 ] identified during dissection an accessory PM that corresponded to the Olewnik et al. [ 10 ] “double PM”. The two rare cases observed by Olewnik et al. [ 10 ] have also been described as case reports by the aforementioned studies. In the published data literature, only two reports described the occurrence of a three-headed PM [ 9 , 12 ]. Olewnik et al. [ 12 ] identified this rare variant in a female cadaver during dissection. The first head originated from the posterior femoral surface, the 2nd head from the LFC, and the GM lateral head, and the 3rd head originated exclusively from the GM lateral head. In this case, all head tendons created a common tendon [ 12 ]. Maslanka et al. [ 9 ] identified a slightly different three-headed PM that fused into a common tendon, with a 1st head originating from the LFC and fused with Kaplan fibers (another variant consisting of connections between the iliotibial band and the distal femur). The other two heads originated from the knee joint capsule and the LFC [ 9 ]. The three-headed PM is a very uncommon variant (only two reports), while the identified bipartite insertion has not been reported. Olewnik et al. [ 12 ] and Maslanka et al. [ 9 ] reports concerning the three-headed PM concluded a common tendon of the variant muscle, while in the current case, the two accessory heads had a bipartite insertion (lateral and medial attachments) via a short and distinct tendon into the calcaneal tendon and via a musculoaponeurotic expansion into the MFC. Zielinska et al. [ 16 ] first reported the occurrence of a four-headed PM, a variant with four independent muscular heads that fuse into a common tendon. Interestingly, in the current literature, there have been theories for a possible relationship between the PM and palmaris longus muscle (PLM). Some studies supported that the two muscles were homologous and equivalent [ 1 ]; however, other studies cited in Gonera et al. [ 5 ] review, pointed out many differences between them. Diogo and Molnar's [ 1 ] theory could be disputed from the embryological background of the muscles. The upper limb muscle development precedes the lower limb muscles; specifically, the PM is fully developed and differentiated in a 14mm embryo length, while the PM is not fully differentiated until a 17mm embryo length [ 2 ]. Therefore, Diogo et al. [ 2 ] highlighted that these two structures appear in different ontogenetic order and are derived from different primordia. Further studies investigating the embryology, comparative anatomy, function, and possible relationship with the PLM are adequate to extend our knowledge of this enigmatic muscle. The PM clinical significance mainly corresponds to its tendon, and it has been proven that be involved in the mid-portion Achilles tendinopathy [ 5 ]. Different morphological types of this tendon can exist, and Gonera et al. [ 5 ] have proposed a classification system with 10 types, while they highlighted that some types are more prevalent to cause Achilles tendinopathy [ 5 ]. Except for pathologic conditions, the PM tendon is a very good candidate for potential donor graft due to its unique morphology (long and thin tendon). The following clinical situations concerning this tendon could potentially help surgeons, such as the replacement of the lateral ankle ligaments, hand tendon reconstruction, and reinforcement of ruptured Achilles tendon [ 5 ]. Conclusion The current report described a rare variant of a three-headed PM with two accessory heads having a bipartite insertion, into the calcaneal tuberosity and the MFC through their musculoaponeurotic expansion. Clinicians, especially orthopaedics, should be aware of PM variants due to their involvement in Achilles tendinopathy. Declarations Ethical approval and consent to participate The cadaver belonged to the Department of Anatomical Dissection and Donation, Medical University of Lodz. Competing interests The authors declare that they have no competing interests. Funding None. Authors’ contribution George Triantafyllou – student – project development, data collection and management, data analysis and manuscript writing. Nicol Zielinska – student – data collection, data analysis, and manuscript editing. Maria Piagkou (DDS, MD, PhD, MSc) – professor – data analysis and manuscript editing. Krzysztof Koptas – student – data collection and manuscript editing. Łukasz Olewnik (D.P.T., PhD) – assistant professor – supervision, data analysis and manuscript editing. All authors have read and approved the manuscript. ACKNOWLEDGMENTS The authors sincerely thank those who donated their bodies to science so that anatomical research could be performed. The knowledge gained from such research can immensely benefit patient care, and these donors and their families deserve our highest gratitude. References Diogo R, Molnar J (2014) Comparative anatomy, evolution, and homologies of tetrapod hindlimb muscles, comparison with forelimb muscles, and deconstruction of the forelimb-hindlimb serial homology hypothesis. Anat Rec 297: 1047–1075, http://dx.doi.org/10.1002/ar.22919 Diogo R, Siomava N, Gitton Y (2019) Development of human limb muscles based on whole-mount immunostaining and the links between ontogeny and evolution. Development 146, http://dx.doi.org/10.1242/dev.180349 Futa BA, Olewnik Ł, Konschake M, Cardona JJ, Iwanaga J, Aragones P, Sanudo J, Tubbs RS (2023) Variant plantaris muscle with degenerated accessory head: Gross and histological analysis. Anat Histol Embryol 52(4):649-652. doi: 10.1111/ahe.12921. Gonera B, Kurtys K, Karauda P, Olewnik Ł, Polguj M (2020) Possible effect of morphological variations of plantaris muscle tendon on harvesting at reconstruction surgery-case report. Surg Radiol Anat 42(10):1183-1188. doi: 10.1007/s00276-020-02463-1. Gonera B, Kurtys K, Paulsen F, Polguj M, LaPrade RF, Grzelecki D, Karauda P, Olewnik Ł (2021) The plantaris muscle - Anatomical curiosity or a structure with important clinical value? - A comprehensive review of the current literature. Ann Anat 235:151681. doi: 10.1016/j.aanat.2021.151681. Heo Y, Lee H, Hwang SJ (2021) Bicipital origin and the course of the plantaris muscle. Anat Cell Biol 54(2):289-291. doi: 10.5115/acb.21.086. Herzog RJ (2011) Accessory plantaris muscle: anatomy and prevalence. HSS J 7(1):52-6. doi: 10.1007/s11420-010-9175-y. Kurtys K, Gonera B, Olewnik Ł, Karauda P, Tubbs RS, Polguj M (2021) Is the plantaris muscle the most undefined human skeletal muscle? Anat Sci Int 96(3):471-477. doi: 10.1007/s12565-020-00586-4. Maślanka K, Zielinska N, Paulsen F, Niemiec M, Olewnik Ł (2023) A three-headed plantaris muscle fused with Kaplan fibers: potential clinical significance. Folia Morphol (Warsz). doi: 10.5603/fm.95513. Olewnik Ł, Kurtys K, Gonera B, Podgórski M, Sibiński M, Polguj M (2020a) Proposal for a new classification of plantaris muscle origin and its potential effect on the knee joint. Ann Anat 231: 151506. doi: 10.1016/j.aanat.2020.151506. Olewnik Ł, Wysiadecki G, Podgórski M, Polguj M, Topol M (2018) The Plantaris Muscle Tendon and Its Relationship with the Achilles Tendinopathy. Biomed Res Int 2018: 9623579. doi: 10.1155/2018/9623579. Olewnik Ł, Zielinska N, Karauda P, Tubbs RS, Polguj M (2020b) A three-headed plantaris muscle: evidence that the plantaris is not a vestigial muscle? Surg Radiol Anat 42(10):1189-1193. doi: 10.1007/s00276-020-02478-8. Silver RL, de la Garza J, Rang M (1985) The myth of muscle balance. A study of relative strengths and excursions of normal muscles about the foot and ankle. J Bone Joint Surg Br 67: 432–437. Smędra A, Olewnik Ł, Łabętowicz P, Danowska-Klonowska D, Polguj M, Berent J (2021) A bifurcated plantaris muscle: another confirmation of its high morphological variability? Another type of plantaris muscle. Folia Morphol (Warsz) 80(3):739-744. doi: 10.5603/FM.a2020.0101. Waśniewska A, Olewnik Ł, Diogo R, Polguj M (2022) Morphological variability of the plantaris muscle origin in human fetuses. Ann Anat 239:151794. doi: 10.1016/j.aanat.2021.151794. Zielinska N, Maślanka K, Wegiel A, Kurtys K, Olewnik Ł (2024) Never undescribed four — headed plantaris muscle. Folia Morphol (Warsz). doi: 10.5603/fm.98753. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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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-4369830","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":300364557,"identity":"298200c8-d063-41a1-9228-fda6ebec47f7","order_by":0,"name":"George Triantafyllou","email":"","orcid":"","institution":"Department of Anatomy, School of Medicine, National and Kapodistrian University of Athens","correspondingAuthor":false,"prefix":"","firstName":"George","middleName":"","lastName":"Triantafyllou","suffix":""},{"id":300364560,"identity":"7d2e0dbb-7d2b-45c2-b2e5-c7d4f89e0a33","order_by":1,"name":"Nicol Zielinska","email":"","orcid":"","institution":"Department of Anatomical Dissection and Donation, Medical University of Lodz","correspondingAuthor":false,"prefix":"","firstName":"Nicol","middleName":"","lastName":"Zielinska","suffix":""},{"id":300364562,"identity":"80e20b4d-a6ac-4cfe-a6a5-d0d528e62d32","order_by":2,"name":"Maria Piagkou","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYJCCAwwMNkAqgTQtaSRqAYLDJGjRbT978MDPHeej+dkT2CQ+1DDYbW8goMXsTF7Cwd4zt3Nn9jxgk5xxjCF5zgFCWg7kGBzgbbudu+FGAps0DxtDsgQhh5mdf2Nw8G/budz9YC3/iNFyI8fgMG/bgdwNEkAtvG0MdkRoeZdwWLYtOXfGmYfNljP7JBKIcFju4Y9v2+xy+9uTD9748M3GnqAWBgYeGIOxAUhIJDaQoAUC7AnrGAWjYBSMgpEGAAdARBSvZUIoAAAAAElFTkSuQmCC","orcid":"","institution":"Department of Anatomy, School of Medicine, National and Kapodistrian University of Athens","correspondingAuthor":true,"prefix":"","firstName":"Maria","middleName":"","lastName":"Piagkou","suffix":""},{"id":300364565,"identity":"65bcc55c-67d3-4fd3-a1d1-f2be70014a17","order_by":3,"name":"Krzysztof Koptas","email":"","orcid":"","institution":"Department of Anatomical Dissection and Donation, Medical University of Lodz","correspondingAuthor":false,"prefix":"","firstName":"Krzysztof","middleName":"","lastName":"Koptas","suffix":""},{"id":300364566,"identity":"c3021174-f2ad-4a4f-8139-5d9d9b7c1794","order_by":4,"name":"Łukasz Olewnik","email":"","orcid":"","institution":"Department of Anatomical Dissection and Donation, Medical University of Lodz","correspondingAuthor":false,"prefix":"","firstName":"Łukasz","middleName":"","lastName":"Olewnik","suffix":""}],"badges":[],"createdAt":"2024-05-04 22:53:59","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4369830/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4369830/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":56363705,"identity":"46bcb543-5cb1-4150-961d-b0b120ef2d76","added_by":"auto","created_at":"2024-05-13 08:17:52","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":376549,"visible":true,"origin":"","legend":"\u003cp\u003eThe three-headed plantaris muscle (PM, dotted cycle area) with the 1\u003csup\u003est\u003c/sup\u003e (typical) 2\u003csup\u003end,\u003c/sup\u003e and 3\u003csup\u003erd\u003c/sup\u003e (accessory) heads. The 2\u003csup\u003end\u003c/sup\u003e and 3\u003csup\u003erd\u003c/sup\u003e heads are inserted partially into the common tendon (CT) formatted by all heads, and via their musculoaponeurotic expansion (MAE) to the medial femoral condyle. LH-lateral head of the gastrocnemius muscle, MH-medial head of the gastrocnemius muscle.\u003c/p\u003e","description":"","filename":"Figure1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4369830/v1/b0f99fd943fe1c104ed4bf6d.jpeg"},{"id":56363061,"identity":"ad264a20-d1af-4c7a-8fd6-c3977bd518c1","added_by":"auto","created_at":"2024-05-13 08:09:52","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":104377,"visible":true,"origin":"","legend":"\u003cp\u003eThe 1\u003csup\u003est\u003c/sup\u003e, 2\u003csup\u003end\u003c/sup\u003e, and 3\u003csup\u003erd\u003c/sup\u003e head of the plantaris muscle after their dissection. MAE- musculoaponeurotic expansion, CT- common tendon.\u003c/p\u003e","description":"","filename":"Figure2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-4369830/v1/cc577a8dbe456b70478d0c03.jpeg"},{"id":56737924,"identity":"a6b0318e-4ad2-4f99-9fd4-a6e3fccc22e0","added_by":"auto","created_at":"2024-05-19 17:44:39","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":764722,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4369830/v1/3a13f3b6-67d0-4862-9d07-929eb5cb1aaf.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A three-headed plantaris muscle with a bipartite insertion of its two accessory heads","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe superficial muscle compartment of the posterior leg is composed of the gastrocnemius muscle (GM), the soleus muscle (SM), and the plantaris muscle (PM), which control the foot and ankle plantar flexion. The PM has the most insignificant influence (0.7% of plantar flexor power) [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The PM seems to have a valuable contribution to hand tendon reconstruction and Achilles tendinopathy [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Typically, the PM has a short and slim belly with a long and thin tendon, that originates from the popliteal surface of the femur and the knee joint capsule, and inserts into the calcaneal tuberosity [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Both muscular and tendinous parts demonstrate high morphological variability [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Rarer PM variants occasionally described were not included in the classifications [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe current cadaveric report describes a three-headed PM, with two accessory heads and an uncommon bipartite insertion of the accessory heads. The morphological variability, as well as possible clinical implications, are further discussed.\u003c/p\u003e"},{"header":"Case Description","content":"\u003cp\u003eA bilateral lower limb dissection for education and research purposes under a pre-established protocol [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] was performed on an 84-year-old male cadaver, derived from a body donation at the Department of Anatomical Dissection and Donation of the Medical University of Lodz. Skin and subcutaneous fat from the popliteal fossa and posterior leg compartment were dissected to expose the related muscles and neurovascular bundle. The GM lateral and medial heads were carefully identified and then dissected, to expose the SM and PM. On the left limb, an uncommon three-headed PM variant with two accessory heads was identified. The three heads originated independently from the femur popliteal surface. The one head (typical) contributed to the PM's long and thin tendon and was typically inserted into the calcaneal tuberosity. The other two (accessory) heads with their short and thin tendon (per head) had a bipartite insertion into the PM's first head (lateral typical attachment) and the medial femoral condyle (MFC) via their musculoaponeurotic complex expansion (medial variant attachment) (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The contralateral PM was identified as typical. A morphometric analysis of the PM variant was also performed. The measurements were taken twice with up to 0.1 mm accuracy using an electric caliper (\u003cem\u003eMitutoyo Corporation, Kawasaki-shi, Kanagawa, Japan\u003c/em\u003e) and are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \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\u003eThe three-headed plantaris muscle (PM) with two accessory heads (2nd and 3rd ) morphometric measurements, expressed in mm.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\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=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eMorphometric parameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003ePlantaris muscle (PM) morphology\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1st head\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2nd head\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3rd head\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCommon tendon\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\u003eLength\u003c/b\u003e (craniocaudal diameter)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e74.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e55.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e50.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e236.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eWidth\u003c/b\u003e (maximum laterolateral diameter)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.70\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe current report describes an uncommon three-headed PM with two accessory heads and a bipartite insertion. In the current literature, only two case reports of a three-headed PM have been described, while the identified insertions were not similar to the present case.\u003c/p\u003e \u003cp\u003eFrom a developmental point of view, the three muscles of the superficial compartment of the posterior leg are derivatives of a common pre-muscular mass. The PM\u0026rsquo;s anlage is located anteriorly to the SM and is partially covered by the GM. In a 12-mm embryo, the PM mass is not differentiated only from GM. Lastly, in a 17-mm embryo, the PM is differentiated from the GM [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e], and differentiation alterations could lead to variant muscle formation.\u003c/p\u003e \u003cp\u003eThe PM muscular origin has been systematically investigated by Olewnik et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], and classified into the following six different origin patterns:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003ePM of type I corresponded to a typical origin from the lateral femoral condyle (LFC), the GM lateral head, and the knee joint capsule, in 48.4%.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePM of type II corresponded to an origin from the knee joint capsule and the GM lateral head, identified in 25%.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePM of type III is characterized by an origin from the LFC, and the knee joint capsule (10.15%).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePM of type IV includes an origin from the LFC, the knee joint capsule, and the iliotibial band (6.25%).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePM of type V includes an origin from the LFC (8.6%).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePM of type VI (2 cases only, 1.6%) were rare PM variants. One variant (0.8%) corresponded to a double PM (two muscular parts and two distinct tendons), and the other variant (0.8%) was characterized as \u0026ldquo;bifurcated PM\u0026rdquo; (two muscular parts that fused into a single tendon).\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eHence, the three-headed PM identified in the current report was not observed in the PM systematic morphological study by Olewnik et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Based on this classification system, Wasniewska et al. [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] studied the PM in human fetuses and concluded the lack of a bipartite PM, i.e., a duplicated PM (distinct double origins) or bifurcated PM (distinct double insertions). Hence, the duplicated or bifurcated PM corresponds to a rare variant, while the three-headed variant is even rarer. The imaging study by Herzog et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] is a unique study referring to the accessory PM, based on a review of 1000 magnetic resonance imaging (MRI). The authors identified the PM accessory form in 6.3% (63 cases), reporting a prevalence higher than the cadaveric studies (1.6%). However, it is unclear if the PM muscular part, as well as PM variant forms can be easily visualized via imaging.\u003c/p\u003e \u003cp\u003eThe existence of PM accessory heads, such as the one described in the present case, has been published before. Olewnik et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] identified a \u0026ldquo;double PM\u0026rdquo; and a \u0026ldquo;bifurcated PM\u0026rdquo; in 0.8% of their sample, per each form. During a forensic autopsy, Smedra et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] observed a PM with two muscular heads that fused to a common tendon, which corresponds to Olewnik et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] \u0026ldquo;bifurcated PM\u0026rdquo;. Futa et al. [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] observed another morphological variant similar to Smedra et al. [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Contrariwise, Kurtys, and co-authors [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] and Heo et al. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] identified during dissection an accessory PM that corresponded to the Olewnik et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] \u0026ldquo;double PM\u0026rdquo;. The two rare cases observed by Olewnik et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] have also been described as case reports by the aforementioned studies.\u003c/p\u003e \u003cp\u003eIn the published data literature, only two reports described the occurrence of a three-headed PM [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Olewnik et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] identified this rare variant in a female cadaver during dissection. The first head originated from the posterior femoral surface, the 2nd head from the LFC, and the GM lateral head, and the 3rd head originated exclusively from the GM lateral head. In this case, all head tendons created a common tendon [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Maslanka et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] identified a slightly different three-headed PM that fused into a common tendon, with a 1st head originating from the LFC and fused with Kaplan fibers (another variant consisting of connections between the iliotibial band and the distal femur). The other two heads originated from the knee joint capsule and the LFC [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The three-headed PM is a very uncommon variant (only two reports), while the identified bipartite insertion has not been reported. Olewnik et al. [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e] and Maslanka et al. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] reports concerning the three-headed PM concluded a common tendon of the variant muscle, while in the current case, the two accessory heads had a bipartite insertion (lateral and medial attachments) via a short and distinct tendon into the calcaneal tendon and via a musculoaponeurotic expansion into the MFC.\u003c/p\u003e \u003cp\u003eZielinska et al. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] first reported the occurrence of a four-headed PM, a variant with four independent muscular heads that fuse into a common tendon.\u003c/p\u003e \u003cp\u003eInterestingly, in the current literature, there have been theories for a possible relationship between the PM and palmaris longus muscle (PLM). Some studies supported that the two muscles were homologous and equivalent [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]; however, other studies cited in Gonera et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] review, pointed out many differences between them. Diogo and Molnar's [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] theory could be disputed from the embryological background of the muscles. The upper limb muscle development precedes the lower limb muscles; specifically, the PM is fully developed and differentiated in a 14mm embryo length, while the PM is not fully differentiated until a 17mm embryo length [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Therefore, Diogo et al. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] highlighted that these two structures appear in different ontogenetic order and are derived from different primordia. Further studies investigating the embryology, comparative anatomy, function, and possible relationship with the PLM are adequate to extend our knowledge of this enigmatic muscle.\u003c/p\u003e \u003cp\u003eThe PM clinical significance mainly corresponds to its tendon, and it has been proven that be involved in the mid-portion Achilles tendinopathy [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Different morphological types of this tendon can exist, and Gonera et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] have proposed a classification system with 10 types, while they highlighted that some types are more prevalent to cause Achilles tendinopathy [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Except for pathologic conditions, the PM tendon is a very good candidate for potential donor graft due to its unique morphology (long and thin tendon). The following clinical situations concerning this tendon could potentially help surgeons, such as the replacement of the lateral ankle ligaments, hand tendon reconstruction, and reinforcement of ruptured Achilles tendon [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThe current report described a rare variant of a three-headed PM with two accessory heads having a bipartite insertion, into the calcaneal tuberosity and the MFC through their musculoaponeurotic expansion. Clinicians, especially orthopaedics, should be aware of PM variants due to their involvement in Achilles tendinopathy.\u003c/p\u003e "},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe cadaver belonged to the Department of Anatomical Dissection and Donation, Medical University of Lodz.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGeorge Triantafyllou \u0026ndash; student \u0026ndash; project development, data collection and management, data analysis and manuscript writing.\u003c/p\u003e\n\u003cp\u003eNicol Zielinska \u0026ndash; student \u0026ndash; data collection, data analysis, and manuscript editing.\u003c/p\u003e\n\u003cp\u003eMaria Piagkou (DDS, MD, PhD, MSc) \u0026ndash; professor \u0026ndash; data analysis and manuscript editing.\u003c/p\u003e\n\u003cp\u003eKrzysztof Koptas \u0026ndash; student \u0026ndash; data collection and manuscript editing.\u003c/p\u003e\n\u003cp\u003eŁukasz Olewnik (D.P.T., PhD) \u0026ndash; assistant professor \u0026ndash; supervision, data analysis and manuscript editing.\u003c/p\u003e\n\u003cp\u003eAll authors have read and approved the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eACKNOWLEDGMENTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors sincerely thank those who donated their bodies to science so that anatomical research could be performed. The knowledge gained from such research can immensely benefit patient care, and these donors and their families deserve our highest gratitude.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDiogo R, Molnar J (2014) Comparative anatomy, evolution, and homologies of tetrapod hindlimb muscles, comparison with forelimb muscles, and deconstruction of the forelimb-hindlimb serial homology hypothesis. Anat Rec 297: 1047\u0026ndash;1075, http://dx.doi.org/10.1002/ar.22919\u003c/li\u003e\n\u003cli\u003eDiogo R, Siomava N, Gitton Y (2019) Development of human limb muscles based on whole-mount immunostaining and the links between ontogeny and evolution. Development 146, http://dx.doi.org/10.1242/dev.180349\u003c/li\u003e\n\u003cli\u003eFuta BA, Olewnik Ł, Konschake M, Cardona JJ, Iwanaga J, Aragones P, Sanudo J, Tubbs RS (2023) Variant plantaris muscle with degenerated accessory head: Gross and histological analysis. Anat Histol Embryol 52(4):649-652. doi: 10.1111/ahe.12921.\u003c/li\u003e\n\u003cli\u003eGonera B, Kurtys K, Karauda P, Olewnik Ł, Polguj M (2020) Possible effect of morphological variations of plantaris muscle tendon on harvesting at reconstruction surgery-case report. Surg Radiol Anat 42(10):1183-1188. doi: 10.1007/s00276-020-02463-1.\u003c/li\u003e\n\u003cli\u003eGonera B, Kurtys K, Paulsen F, Polguj M, LaPrade RF, Grzelecki D, Karauda P, Olewnik Ł (2021) The plantaris muscle - Anatomical curiosity or a structure with important clinical value? - A comprehensive review of the current literature. Ann Anat 235:151681. doi: 10.1016/j.aanat.2021.151681.\u003c/li\u003e\n\u003cli\u003eHeo Y, Lee H, Hwang SJ (2021) Bicipital origin and the course of the plantaris muscle. Anat Cell Biol 54(2):289-291. doi: 10.5115/acb.21.086.\u003c/li\u003e\n\u003cli\u003eHerzog RJ (2011) Accessory plantaris muscle: anatomy and prevalence. HSS J 7(1):52-6. doi: 10.1007/s11420-010-9175-y.\u003c/li\u003e\n\u003cli\u003eKurtys K, Gonera B, Olewnik Ł, Karauda P, Tubbs RS, Polguj M (2021) Is the plantaris muscle the most undefined human skeletal muscle? Anat Sci Int 96(3):471-477. doi: 10.1007/s12565-020-00586-4.\u003c/li\u003e\n\u003cli\u003eMaślanka K, Zielinska N, Paulsen F, Niemiec M, Olewnik Ł (2023) A three-headed plantaris muscle fused with Kaplan fibers: potential clinical significance. Folia Morphol (Warsz). doi: 10.5603/fm.95513.\u003c/li\u003e\n\u003cli\u003eOlewnik Ł, Kurtys K, Gonera B, Podg\u0026oacute;rski M, Sibiński M, Polguj M (2020a) Proposal for a new classification of plantaris muscle origin and its potential effect on the knee joint. Ann Anat 231: 151506. doi: 10.1016/j.aanat.2020.151506.\u003c/li\u003e\n\u003cli\u003eOlewnik Ł, Wysiadecki G, Podg\u0026oacute;rski M, Polguj M, Topol M (2018) The Plantaris Muscle Tendon and Its Relationship with the Achilles Tendinopathy. Biomed Res Int 2018: 9623579. doi: 10.1155/2018/9623579.\u003c/li\u003e\n\u003cli\u003eOlewnik Ł, Zielinska N, Karauda P, Tubbs RS, Polguj M (2020b) A three-headed plantaris muscle: evidence that the plantaris is not a vestigial muscle? Surg Radiol Anat 42(10):1189-1193. doi: 10.1007/s00276-020-02478-8.\u003c/li\u003e\n\u003cli\u003eSilver RL, de la Garza J, Rang M (1985) The myth of muscle balance. A study of relative strengths and excursions of normal muscles about the foot and ankle. J Bone Joint Surg Br 67: 432\u0026ndash;437.\u003c/li\u003e\n\u003cli\u003eSmędra A, Olewnik Ł, Łabętowicz P, Danowska-Klonowska D, Polguj M, Berent J (2021) A bifurcated plantaris muscle: another confirmation of its high morphological variability? Another type of plantaris muscle. Folia Morphol (Warsz) 80(3):739-744. doi: 10.5603/FM.a2020.0101.\u003c/li\u003e\n\u003cli\u003eWaśniewska A, Olewnik Ł, Diogo R, Polguj M (2022) Morphological variability of the plantaris muscle origin in human fetuses. Ann Anat 239:151794. doi: 10.1016/j.aanat.2021.151794.\u003c/li\u003e\n\u003cli\u003eZielinska N, Maślanka K, Wegiel A, Kurtys K, Olewnik Ł (2024) Never undescribed four \u0026mdash; headed plantaris muscle. Folia Morphol (Warsz). doi: 10.5603/fm.98753.\u003c/li\u003e\n\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":"plantaris muscle, variation, accessory head, dissection, morphology","lastPublishedDoi":"10.21203/rs.3.rs-4369830/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4369830/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe plantaris muscle consists of a small muscular and a long tendinous part and is located at the superficial compartment of the posterior leg. The purpose of the current cadaveric report is to describe a rare variant of the plantaris muscle. During a routine dissection, a three-headed plantaris with two accessory heads was identified with a variant insertion of the two accessory heads. All heads originated from the femur popliteal surface, independently the one from the other. The first head contributed to the long and thin calcaneal tendon, and the two accessory heads were mainly inserted via their musculoaponeurotic expansion into the medial femoral condyle. The planatris muscle morphological variability has been extensively studied lately. The incidence of the two-headed muscle has been estimated at 1.6%, while the three-headed muscle corresponds to an even rarer variation.\u003c/p\u003e","manuscriptTitle":"A three-headed plantaris muscle with a bipartite insertion of its two accessory heads","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-05-13 08:09:47","doi":"10.21203/rs.3.rs-4369830/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":"6b975037-692b-43ce-8246-756649c29287","owner":[],"postedDate":"May 13th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-05-19T17:36:32+00:00","versionOfRecord":[],"versionCreatedAt":"2024-05-13 08:09:47","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4369830","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4369830","identity":"rs-4369830","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}