Pronator Teres Tendon

tendo musculi pronatoris teretis

The pronator teres has two heads: the humeral head from the medial epicondyle (common flexor origin) and the ulnar head from the coronoid process of the ulna. The combined muscle belly crosses the forearm diagonally to insert via its flat tendon onto the lateral radius (mid-shaft, at the radial tuberosity level). The median nerve passes between the two heads of the muscle. Pronator teres acts as a forearm pronator and as a weak elbow flexor.

Region: Forearm

Clinical Relevance

Clinical Notes

Pronator teres syndrome is entrapment of the median nerve between the two pronator teres heads, producing forearm pain and median nerve symptoms including loss of sensation in the radial three digits and thenar weakness — distinguished from carpal tunnel syndrome by preserved sensation (palmar cutaneous branch) and reproducibility with resisted pronation. The pronator teres tendon is used in flexor pronator mass surgery for medial epicondylitis where the humeral head origin is partially released. In cerebral palsy treatment, pronator teres fractional lengthening or release reduces spastic pronation deformity.

Pathology

Common Injuries & Conditions

Pronator Teres Syndrome Median Nerve Entrapment

Median nerve entrapment between the humeral and ulnar heads of pronator teres produces forearm pain and paresthesiae in the radial three digits reproduced by resisted forearm pronation with the elbow extended; distinguished from carpal tunnel syndrome by involvement of the palmar cutaneous branch (medial wrist numbness) and by normal NCS at the wrist level.