The accessory soleus.
D000328:Adult; D000842:Ankle / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000503:physiopathology; D000843:Ankle Joint; D006801:Humans; D008297:Male; D009132:Muscles / Q000002:abnormalities* / Q000098:blood supply / Q000294:innervation / Q000601:surgery; D005082:Physical Exertion; D011859:Radiography