Accessory Soleus Muscle in a 79‐Year‐Old Female Cadaver: A Case Report

In the present case report, we describe characteristics regarding a rare accessory soleus muscle (ASM) that was discovered and measured. The ASM is found in about 6% of people, and is most commonly asymptomatic (Mukish et al., 2012). The most common symptomatic presentation includes a soft mass in the posteromedial distal third of the leg. Pain is also present in around two‐thirds of symptomatic cases (Mukish et al., 2012). This unilateral anomaly was found during a routine dissection of the left lower ankle in a 79 year old female cadaver. In the present case, the ASM tendon originates from the middle of the tibia and inserts via tendinous insertion onto the medial surface of the calcaneus; this is one of four possible insertion variations already described in the literature. This particular insertion variation is described as Type A (Tubbs et al., 2016). The length of the muscle is [17cm] at the insertion point of the superior tendon to the inferior tendon. This accessory soleus variation has been shown to cause various clinical implications such as tibial nerve compression neuropathy in patients (Badr et al., 2020). Clinical symptoms experienced by patients due to presence of ASM are significant enough to require surgical removal of this muscle to relieve symptoms (Badr et al., 2020). Due to both the known and unknown clinical implications of the variation, it is pertinent to properly describe this so as to benefit future clinical and surgical outcomes for all patients.