Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Austria.
Division of Anatomy, Center for Anatomy and Cell Biology, Medical University of Vienna, Austria; Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Austria.
Ann Anat. 2023 Oct;250:152164. doi: 10.1016/j.aanat.2023.152164. Epub 2023 Oct 6.
The peroneus tertius muscle (PT) is one of the extensor muscles of the lower leg, often described as a variable separation from the extensor digitorum longus muscle (EDL). According to literature it has six different types of insertion, one of them (Olewnik Type IV) having two tendons inserting to the fifth metatarsal bone (FMTB). Morphometric data about this type of insertion is sparse, especially the relation between the two tendons, albeit the PT is suspected to contribute to stress fractures of the FMTB. Therefore, we examined this type of insertion to give detailed information on the tendons, the insertion points and the respective relations.
We examined 27 lower extremities of embalmed human bodies (12 paired, 15 single sided; 12 right and 15 left) with a distinguishable PT with two tendons inserting to the FMTB (Olewnik IV). The specimens were obtained of an undergrad dissection program, which in turn obtained them from a body donation program. After dissection of the PT and photo documentation in situ, resection and measurement of morphological properties of the tendons were performed with the PT attached to the fifth metatarsal bone.
Results of the respective measurements yielded a wide range of variation, especially in the insertion point of the anterior tendon on the fifth metatarsal and the relation between the two tendons, but with no significant difference between sides or sex, except for the length of the posterior tendon between sex. The distance between the base of the FMTB and posterior tendon varies from 0 to 9 mm, with one outlier at 24 mm (mean = 3.9 ± 4.8 mm), the distance between the insertions from 0 to 15 mm (mean = 4.7 ± 4.7 mm), resulting in how far of the FMTB the anterior tendon reaches varying from 17 to 60 mm (mean = 39.6 ± 11.5 mm) or 22-98% (mean = 64 ± 19%).
Our findings give a detailed overview of the morphological features the PTT can have, when attached with two tendons to the FMTB. Especially the varying relationship between those two insertions and varying point of the anterior insertion are of interest, as they might support its complex role in the occurrence of fractures of the fifth metatarsal by providing different amounts of torsional stress and its tendons can be used as tendon-grafts.
外展第三肌（PT）是小腿伸肌之一，常被描述为与趾长伸肌（EDL）的分离。根据文献，它有六种不同的插入类型，其中一种（Olewnik 型 IV）有两条肌腱插入第五跖骨（FMTB）。关于这种插入类型的形态计量数据很少，特别是两条肌腱之间的关系，尽管 PT 被怀疑会导致 FMTB 的应力性骨折。因此，我们检查了这种类型的插入，以提供有关肌腱、插入点和各自关系的详细信息。
我们检查了 27 具经过防腐处理的人体下肢（12 对，15 单侧；12 右，15 左），这些下肢都有两条肌腱插入 FMTB（Olewnik IV）的可区分的 PT。标本取自本科解剖课程，而解剖课程则从遗体捐赠计划中获得标本。在对 PT 进行解剖和原位摄影记录后，将 PT 附着在第五跖骨上进行肌腱的形态学特性的切除和测量。
各自测量结果的变化范围很广，特别是在前肌腱在第五跖骨上的插入点和两条肌腱之间的关系，但除了性别之间后肌腱的长度外，两侧或性别之间没有显著差异。FMTB 基部和后肌腱之间的距离为 0 至 9 毫米，有一个离群值为 24 毫米（平均值为 3.9 ± 4.8 毫米），插入点之间的距离为 0 至 15 毫米（平均值为 4.7 ± 4.7 毫米），因此前肌腱到达 FMTB 的距离从 17 毫米到 60 毫米不等（平均值为 39.6 ± 11.5 毫米）或 22-98%（平均值为 64 ± 19%）。
我们的研究结果提供了关于当 PT 有两条肌腱附着在 FMTB 上时，PTT 可能具有的形态特征的详细概述。特别是两条插入之间的关系和前插入的变化点很有趣，因为它们可能通过提供不同量的扭转力来支持其在第五跖骨骨折发生中的复杂作用，并且它们的肌腱可以用作肌腱移植物。
