06/12/2026
A Seatbelt Saved His Life… But May Have Injured a Nerve
Motor vehicle collisions can produce injuries that are easy to miss. This patient developed visible atrophy of the lower portion of the right pectoralis major muscle following a collision. At first glance, many would focus on the spine, shoulder, or chest wall. However, careful examination raises concern for a possible injury involving the medial pectoral nerve, the nerve that helps supply the lower fibers of the pectoralis major muscle.
What makes this case particularly interesting is that prior testing failed to identify the source of the problem. Unfortunately, electrodiagnostic studies are only as good as the muscles and nerve pathways examined. If the involved muscle is not directly studied, important findings can be missed.
Of course, other possibilities remain on the differential diagnosis, including brachial plexus injury, cervical radiculopathy, or direct muscle and tendon injury. This is why a detailed history, thorough physical examination, and properly targeted diagnostic testing remain critical.
Sometimes the diagnosis is not hidden—it is sitting right in front of us. The challenge is knowing where to look.
At RES Physical Medicine & Rehabilitation, we believe every patient deserves a comprehensive evaluation designed to identify the true source of their symptoms, not just treat the pain.
