Purpose

The plantaris muscle (PM) is typically characterized by a short, slim and spindle-shaped muscle belly and long, thin tendon. It is situated posterior to the popliteal muscle, and anterior to the lateral head of the gastrocnemius muscle (GM). Little information exists regarding the high variability of origin of the PM. The main aim of the study was hence to characterize the morphology of the PM and its place of origin, classify it and evaluate its prevalence.

Methods

Classical anatomical dissection was performed on 142 lower limbs (77 left, and 65 right) fixed in 10% formalin solution. The morphology of the origin of the PM and its prevalence was evaluated.

Results

The PM was present in 128 lower limbs (90.1%). Six types of origin were observed, the most common being Type I (48.4%). This type was divided into two subtypes (A–B): subtype A attaching to the lateral head of the GM, lateral femoral condyle and to the capsule of the knee joint, and subtype B, attaching to the lateral head of the GM, the lateral femoral condyle, knee joint capsule and the popliteal surface of the femur. The second most common type was Type II (25%), attaching to the capsule of the knee joint and, indirectly, to the lateral head of the GM through the lateral femoral condyle. The third most common type was Type III (10.15%), attaching to the lateral femoral condyle and the knee joint capsule. Type IV (6.25%), the rarest type, attached to the lateral femoral condyle, knee joint capsule and to the iliotibial band. Type V (8.6%) originated only from the lateral condyle of the femur. Type VI (1.6%) contains only "rare cases".

Conclusion

The PM presents high morphological variability, and its status as a residual muscle should be reconsidered. Our presented classification of its types of origin is a valuable addition for both clinicians and anatomists.

Level of Evidence – II Basic Science Research

中文翻译：

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建议对plant肌起源进行新的分类及其对膝关节的潜在影响。

目的

肌（PM）的典型特征是腹部短而细长，呈纺锤形，肌腱长而细。它位于the肌的后方，腓肠肌（GM）的外侧头的前部。关于PM来源高度可变的信息很少。因此，该研究的主要目的是表征PM的形态及其起源，分类和评估其患病率。

方法

对固定在10％福尔马林溶液中的142下肢（左77和右65）进行经典解剖解剖。评价了PM起源的形态及其患病率。

结果

PM存在于128个下肢中（90.1％）。观察到六种起源，最常见的是第一类（48.4％）。这种类型分为两种亚型（AB）：亚型A附着在GM的外侧头，股骨con和膝关节囊上； B型亚种，附着在GM的外侧头上，股外侧，膝关节囊和股骨the面。第二种最常见的类型是II型（25％），其附着在膝关节的囊膜上，并通过股骨外侧con间接附着在GM的侧头上。第三类最常见的类型是III型（10.15％），附着在股外侧con和膝关节囊上。IV型（6.25％）是最罕见的类型，附着在股外侧lateral，膝关节囊和胫束带上。V型（8。6％）仅起源于股骨外侧con。VI类型（1.6％）仅包含“罕见案例”。

结论

PM具有较高的形态变异性，应重新考虑其作为残留肌肉的状态。我们提出的有关其起源类型的分类对于临床医生和解剖学家都是有价值的补充。

证据水平– II基础科学研究