M62.1 - Other rupture of muscle (nontraumatic)
M62.13 - Other rupture of muscle (nontraumatic), forearm
M62.131 - Other rupture of muscle (nontraumatic), right forearm
M62.132 - Other rupture of muscle (nontraumatic), left forearm
M62.139 - Other rupture of muscle (nontraumatic), unspecified forearm