Pectoralis minor syndrome.

Pectoralis minor syndrome (PMS) is defined as compression of the brachial plexus (BP) nerves, axillary artery, and axillary vein under the pectoralis minor muscle. The symptoms of PMS resemble supraclavicular compression of the neurovascular bundle, with shoulder, neck, chest, and arm pain, and paresthesia and weakness in the arm and hand. The diagnosis of PMS can be confused with other upper extremity pain syndromes. A detailed history, including occupation, daily activities, sports, and trauma, is critical in the diagnosis, together with physical examination findings. Radiological examinations, including direct radiography, computed tomography, magnetic resonance imaging, and electrophysiological tests, are also helpful for the differential diagnosis. Arterial and venous Doppler ultrasound, including dynamic investigation, can display arterial and venous compression. Injection tests are used to confirm the definitive diagnosis. Conservative treatment is successful in most patients, and surgical treatment is considered in unresponsive cases.