Introduction

The soleus muscle (SM) is located in the superficial posterior compartment of the leg, together with the gastrocnemius muscle (GM) and plantaris muscle. There is little information on the morphological variability (pennation) of the SM. The aim of the study is to characterize the variations in the morphology of the pennation of the SM and to create the first accurate classification.

Material and methods

Eighty lower limbs (40 left, and 40 right) fixed in 10% formalin solution were examined. The morphology of the central tendon, medial and lateral aponeuroses was evaluated, together with the pennation angle.

Results

In all cases, the soleus muscle was present. Four types could be distinguished based on muscle fibre morphology. In order of frequency: Type 1 – bipennate (43.75%); Type 4 – non-pennate (36.25%); Type 2 – unipennate (15%); Type 3 – multipennate (5%). No significant difference in type distribution was observed with regard to body side (p = 0.9018) or gender (p = 0.0844).

Conclusion

The soleus muscle is characterized by high morphological variability. Based on the pennation angle, four types (1–4) of soleus muscle are distinguishable.

中文翻译：

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比目鱼肌形态新分类的建议。

介绍

比目鱼肌（SM）与腓肠肌（GM）和plant肌一起位于腿的浅表后室。关于SM的形态变异性（假名）的信息很少。该研究的目的是表征SM垂体的形态变化并建立第一个准确的分类。

材料与方法

检查了在10％福尔马林溶液中固定的80个下肢（左40个，右40个）。评价了中央肌腱，内侧和外侧腱膜的形态以及垂体角度。

结果

在所有情况下，均存在比目鱼肌。根据肌肉纤维形态可以区分四种类型。按频率顺序排列：类型1 –二联酸盐（43.75％）；类型4 –非笔形（36.25％）；类型2 –单萜（15％）；类型3 –多笔形（5％）。在体侧（p  = 0.9018）或性别（p  = 0.0844）方面，没有观察到类型分布的显着差异。

结论

比目鱼肌的特征是高形态变异性。根据垂体角度，可以识别四种类型的（1-4）比目鱼肌。