Nerve Injuries around the Shoulder.

Nerve injuries around the shoulder are common. They usually occur as a result of motor vehicle accidents, gunshot or athletic injuries, or overuse and chronic repetitive stress often observed in sports involving repetitive overhead or throwing activities. The mechanisms of nerve injury include direct pressure, repetitive microtrauma, and compression- or stretch-induced ischemia. The severity and extent of compression is related to the degree of the nerve injury. Several nerve injury grading systems have been developed, allowing for the correlation between microscopic changes occurring after the injury and the patient's symptoms; recovery and prognosis is related to the type and severity of the injury. Distinct clinical syndromes involving the shoulder joint area can develop after injuries to the axillary, musculocutaneous, suprascapular, long thoracic, and spinal accessory nerves, as well as the proximal brachial plexus trunks and the lower cervical nerve roots. When a patient complains of pain, weakness, or paresthesia in the absence of known bone, soft tissue, or vascular injury, nerve injury must be suspected. This article summarizes the most common nerve injuries around the shoulder and discusses the classification, mechanism, treatment, and prognosis for these injuries.