Fig. 1

Accessory muscle. Sagittal T1-WI. An accessory soleus (black asterisk) is seen anterior-inferior to the soleus muscle (white asterisk), arising from the tibia (origin not shown) and with a tendinous insertion onto the superior surface of the calcaneus anteromedial to the Achilles tendon (arrow). This is just one of the five types of accessory soleus that have been described on the basis of insertion characteristics