Separation of muscle (nontraumatic), left forearm

This code signifies a spontaneous or atraumatic separation of muscle fibers within the left forearm. It describes a condition where muscle tissue detaches or tears without an external injury or force. This can manifest as a palpable defect or significant pain and dysfunction.

Use this code when documentation clearly indicates a non-traumatic muscle separation in the left forearm. This typically occurs in cases of muscle rupture due to degenerative changes, overuse, or underlying systemic conditions, rather than an acute injury. Physician notes should specify the atraumatic nature and the affected anatomical location.

• Ensure documentation explicitly states "nontraumatic" or provides context ruling out an external injury.
• Distinguish from traumatic muscle tears (S46.312A-S46.392S) which are coded differently.
• Confirm the laterality (left) and anatomical site (forearm) are clearly documented to support this specific code.