Anomalous muscle in the leg: soleus accessorium.

In the last 4 years we have had the opportunity to investigate an anomalous muscle mass on the medial aspect of the distal leg of three young athletes. A review of the clinical literature has revealed only nine reported cases of a similar muscle mass in this area. Surgical exploration was carried out in each of our three cases with relief of symptoms in two of the cases following decompression of the overlying fascial sheath. We believe this muscle to represent the soleus accessorius and its presence, which may be rare. The presence of this muscle should be considered in the differential diagnosis of a symptomatic or asymptomatic mass of the posteromedial aspect of the distal leg. Surgical exploration and fascial release is recommended.