From 1965 to 1981, eleven patients with compression of the sensory portion of the musculocutaneous nerve by the biceps aponeurosis and tendon were seen at Duke University Medical Center and followed until the completion of treatment. Four patients responded to non-operative management. Compression of the nerve by the biceps aponeurosis and tendon against the fascia of the brachialis muscle accounted for the characteristic finding of nerve-flattening and loss of vascular markings in the seven patients who required surgery. Surgical decompression relieved the symptoms in all seven of them.