Anatomy, Shoulder and Upper Limb, Pronator Teres

The word pronator originates from the Latin meaning “lying face downward,” and this appropriately describes the function of the pronator teres, which rotates the forearm so that the palm faces downwards. The pronator teres is a fusiform forearm muscle found in the superficial layer of the anterior compartment of the forearm. Its primary function is to pronate the forearm and assist in forearm flexion. This muscle, therefore, has essential involvement in sporting activities. The median nerve innervates the pronator teres as it travels through the pronator teres’ two heads originating from the humerus and the ulna. The median nerve is thus at risk for compression at this site in cases of pronator teres overuse or even hypertrophy. Clinically, median nerve compression at this site is known as pronator teres syndrome. Patients with this syndrome most commonly experience pain and numbness, but motor dysfunction may also be present in some cases.