M62.1 - Other rupture of muscle (nontraumatic)
M62.16 - Other rupture of muscle (nontraumatic), lower leg
M62.161 - Other rupture of muscle (nontraumatic), right lower leg
M62.162 - Other rupture of muscle (nontraumatic), left lower leg
M62.169 - Other rupture of muscle (nontraumatic), unspecified lower leg