Introduction

The extensor hallucis longus originates from about the middle three fifths of the anterior surface of the fibula, medial to the origin of the extensor digitorum longus, and inserts into the distal phalanx of the great toe. The goal of this study was to examine the insertion of the extensor hallucis longus tendon and thus prepare its first classification in human fetuses.

Material and Methods

Fifty spontaneously-aborted human fetuses (26 male, 24 female, 100 lower limbs), aged 18–38 weeks of gestation, were examined.

Results

The classification comprised three types of extensor hallucis longus insertion. The most common was type I (68%), which was characterized by a single tendon that ends as an extensor hood inserting into the dorsal aspect of the base of the distal phalanx of the great toe. The second most frequent was type II (27%), which was characterized by two distal tendons: the dominant one ends as an extensor hood inserting into the distal phalanx of the great toe, and the auxiliary inserts separately into the dorsal aspect of the proximal phalanx of the great toe, medial to the insertion of the extensor hallucis brevis tendon. Finally, type III (5%), the least frequent type, was characterized by two distal tendons: the dominant one ends as an extensor hood inserting into the distal phalanx of the great toe, and the auxiliary connects to the tendon of the extensor hallucis brevis.

Conclusion

The extensor hallucis longus demonstrates great variability in the approach of its tendon to the foot, at least in fetuses, as indicated by this initial classification.

中文翻译：

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人类胎儿拇长伸肌的形态变异性

介绍

拇长伸肌起源于腓骨前表面约五分之三的中部，在趾长伸肌起源的内侧，并插入大脚趾的远端指骨。这项研究的目的是检查拇长伸肌腱的插入，从而准备其在人类胎儿中的第一个分类。

材料与方法

检查了 50 名自然流产的人类胎儿（26 名男性，24 名女性，100 名下肢），年龄在 18-38 周之间。

结果

分类包括三种类型的拇长伸肌插入。最常见的是 I 型 (68%)，其特征是单个肌腱末端为伸肌罩，插入大脚趾远端指骨基部的背面。第二常见的是 II 型（27%），其特征是两个远端肌腱：主导的一端作为伸肌罩插入大脚趾的远端指骨，辅助的一端分别插入近端的背侧大脚趾的指骨，在拇短伸肌腱插入点的内侧。最后，最不常见的 III 型 (5%) 的特征是两个远端肌腱：占优势的一端作为伸肌罩插入大脚趾的远端指骨，

结论

正如最初的分类所示，拇长伸肌在其肌腱接近足部的过程中表现出很大的变异性，至少在胎儿中是这样。