Introduction

The plantaris muscle (PM) is a small, fusiform muscle located between the gastrocnemius muscle (GM) and soleus muscle (SM). PM supports movements of the knee and ankle. This muscle presents a great variability, and also has a high clinical significance. Nevertheless, data concerns morphology and morphometry of the origin of PM in human fetuses are scarce.

Material and methods

Forty-seven spontaneously-aborted human fetuses (23 male, 24 female) aged 18–38 weeks of gestation were examined. The morphology and morphometry of the origin of PM were evaluated.

Results

PM was present in 74 lower limbs (78.7%), and absent on 20 limbs (21.3%). We distinguished VI types of the proximal attachment of PM. Belly width and thickness, as well as thickness of the tendon and MT junction differed significantly between types of PM origin.

Conclusions

We distinguished six (I–VI) types of origin of PM in human fetuses. The most common type was type Ia, characterized by an attachment to the lateral head of GM, lateral femoral condyle and to the knee joint capsule. Our results of PM anatomical variation in fetuses will pave the way for detailed comparisons with studies carried out on adult cadavers.

中文翻译：

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人类胎儿跖肌起源的形态变异性

介绍

跖肌 (PM) 是位于腓肠肌 (GM) 和比目鱼肌 (SM) 之间的小的梭形肌肉。PM 支持膝盖和脚踝的运动。这种肌肉呈现出很大的变异性，也具有很高的临床意义。然而，关于人类胎儿 PM 起源的形态学和形态测量学的数据很少。

材料与方法

检查了 47 个自然流产的人类胎儿（23 名男性，24 名女性），妊娠 18-38 周。对 PM 来源的形态学和形态学进行了评估。

结果

PM存在于74条下肢（78.7%），20条下肢（21.3%）不存在。我们区分了 PM 近端附着的 VI 类型。腹部宽度和厚度，以及肌腱和 MT 连接处的厚度在 PM 起源类型之间存在显着差异。

结论

我们区分了人类胎儿 PM 的六种 (I-VI) 类型。最常见的类型是 Ia 型，其特征是附着于 GM 的外侧头、股骨外侧髁和膝关节囊。我们对胎儿 PM 解剖变异的结果将为与对成人尸体进行的研究进行详细比较铺平道路。