The pronator teres syndrome is an entrapment neuropathy of the median nerve as it passes between the two heads of which muscle?

The pronator teres syndrome is an entrapment neuropathy of the median nerve as it passes between the two heads of which muscle?

• A. Brachioradialis
• B. Pronator teres
• C. Supinator
• D. Flexor carpi radialis

Answer: (B)

Pronator teres syndrome occurs when the median nerve is compressed as it passes through a small tunnel formed by the two heads of the pronator teres muscle. The pronator teres has a superficial head originating from the medial epicondyle of the humerus and a deep head from the coronoid process of the ulna. The space between these two heads can constrict the nerve, leading to forearm pain and sensory or motor symptoms in the median-nerve distribution. Other muscles listed don’t create that classic two-headed tunnel for the median nerve. The brachioradialis is on the radial side and relates to the radial nerve; the supinator can entrap the posterior interosseous nerve (a branch of the radial nerve) rather than the median nerve; the flexor carpi radialis is a flexor whose course is not the typical compression site for median-nerve entrapment.

Pronator teres syndrome occurs when the median nerve is compressed as it passes through a small tunnel formed by the two heads of the pronator teres muscle. The pronator teres has a superficial head originating from the medial epicondyle of the humerus and a deep head from the coronoid process of the ulna. The space between these two heads can constrict the nerve, leading to forearm pain and sensory or motor symptoms in the median-nerve distribution.

Other muscles listed don’t create that classic two-headed tunnel for the median nerve. The brachioradialis is on the radial side and relates to the radial nerve; the supinator can entrap the posterior interosseous nerve (a branch of the radial nerve) rather than the median nerve; the flexor carpi radialis is a flexor whose course is not the typical compression site for median-nerve entrapment.