The accessory soleus muscle.

The accessory soleus muscle, as a clinically significant finding, has been infrequently reported in the English literature. Prior to the advent of the computerized tomography (CT) scanner, the diagnosis could only be suspected and was confirmed only at surgery. The CT scanner assists in differential diagnosis of a painful ankle mass and reveals the size and extent of the mass as well as its density. The density determinations in this case were most consistent with a muscle mass and led to the preoperative diagnosis of an accessory soleus muscle.