Pronator Teres Syndrome (PTS) is a condition in which the median nerve, a major nerve running from the neck through the arm to the hand, becomes compressed by the pronator teres muscle near the elbow. This muscle helps rotate the forearm so the palm faces downward. PTS is the second most common type of median nerve compression after carpal tunnel syndrome and accounts for about 9–12% of median nerve entrapments.

Patients typically experience aching discomfort in the forearm, with tingling or numbness into the thumb, index, middle, and half of the ring finger. Symptoms can mimic carpal tunnel syndrome but have key differences: unlike carpal tunnel, PTS symptoms usually do not worsen at night and are often increased with repetitive forearm pronation or supination rather than wrist flexion alone. Many patients also report weakness in gripping or pinching, leading to difficulty with fine motor tasks.

Clinical evaluation often shows tenderness over the pronator teres muscle and the medial epicondyle. Special tests, like the pronator compression test or resisted pronation test, help reproduce symptoms and confirm the site of nerve entrapment. The median nerve may also be compressed at other nearby structures in the elbow region, such as the bicipital aponeurosis, the arch of the flexor digitorum superficialis, or the anterior interosseous nerve, which can lead to specific motor weaknesses.

PTS is more common in people who perform repetitive forearm movements, such as carpenters, mechanics, athletes, or weightlifters. Early recognition is important to relieve nerve pressure, prevent lasting weakness, and restore normal function in the forearm and hand.