Upper extremity neuromuscular injuries in athletes.

Upper extremity muscle and nerve injuries in athletes are important causes of lost playing time and suboptimal performance. Although most muscle injuries are self-limited, imaging may be indicated in select situations for diagnostic and prognostic purposes, to investigate potential complications of injury, and for instituting prompt therapy to hasten recovery. MRI is particularly sensitive to soft tissue abnormalities seen in muscle injury, and it can reliably diagnose and stage direct injuries such as contusions and lacerations, and indirect injuries such as strains, delayed-onset muscle soreness, and exertional compartment syndrome. Upper extremity peripheral nerve injuries may be compressive or noncompressive in etiology, with certain sports and activities rendering particular nerves vulnerable to characteristic injuries. Initial evaluation includes a complete history, physical examination, and electrodiagnostic studies. MRI and ultrasound assessment of the nerves, surrounding tissues, and innervated muscles can provide localizing, diagnostic, and prognostic information that complements clinical and electrodiagnostic testing.