Tuesday, March 11, 2008

Sharks and the Soleus Muscle

In life, sometimes you don't get what you expect. The Shark Shield is an electronic device designed to be attached to a surfboard, to repel sharks. During testing, instead of repelling sharks, it attracted a 12-foot great white shark, which promptly inhaled it as a nice snack. Not what the designers expected. Oh well, back to the drawing board....

In radiology, too, sometimes you encounter something besides what you expect.

A common clinical scenario is calf pain after a tennis injury. This is most often due to a tear of the medial head of the gastrocnemius muscle, or a tear of the plantaris muscle. Clinicians are sometimes concerned about an Achilles tear as well. When I hear this history, I usually look for these things. In this case, however, I saw something a little different:

Coronal STIR images reveal edema in the mid- and distal third of the right calf (red arrows). The left calf (yellow arrows) is normal.

Axial images depict a partial tear of the soleus muscle (red arrows). The soleus muscle of the left calf (yellow arrows) is normal:

Thus, when you there is a history of calf pain after trauma, consider that any of the components of the Achilles myotendinous unit (triceps surae) can tear. Thus, examine the medial and lateral heads of the gastrocnemius, and the soleus. Tears of the plantaris tendon should also be looked for (Helms et al., Radiology 1995, 195:201-203).

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