is flexed to a right angle, then pronator teres will turn the hand so that the palm faces inferiorly. It is assisted in this action by pronator quadratus. It also weakly flexes the elbow, or assists in flexion at the elbow when there is strong resistance. Clinical significance Pronator teres syndrome is one cause of wrist pain. It is a type of neurogenic pain. Patients with the pronator teres syndrome have numbness in median nerve distribution with repetitive pronation/supination of the forearm, not flexion and extension of the elbow Early fatigue of the forearm muscles is seen with repetitive stressful motion, especially pronation EMG may show only mildly reduced conduction velocities Despite their anatomic proximity, patients with pronator teres syndrome do not have a higher incidence of AIN syndrome Other sites of compression: Ligament of Struthers Lacertus fibrosis Proximal arch of the FDS Rare causes such as following tendon transfers for radial palsy Dissimilarity to CTS: Positive Tinel's sign in forearm rather than at wrist Negative Phalen's maneuver Dysesthesia of palmar triangle Pain on resistance to pronation Pain in forearm on resistance to isolated flexion of the PIP joint of long and ring fingers In C5 tetraplegia or radial nerve palsy patients, pronator teres tendon can be rerouted, so called tendon transfer, to extensor carpi radialis brevis tendon to restore wrist extension. Etymology The word pronator comes from the Latin pronus, which means “inclined forward or lying face downward”, and has to do with the muscle's action being pronation of the forearm. The Latin term teres, which means "round or cylindrical shaped" or "long and round", refers to the shape of the muscle. The indirect English translation of pronator teres is therefore: cylindrical muscle that turns the forearm (and the palm along with it) down. Additional images References External links Elbow flexors Forearm pronators Muscles of the upper limb