PINS stands for posterior interosseous nerve syndrome and is located between which bones?

PINS stands for posterior interosseous nerve syndrome and is located between which bones?

• A. Between carpal bones and metacarpals
• B. Between radius and ulna
• C. Between ulna and carpal bones
• D. Between humerus and radius

Answer: (B)

Posterior interosseous nerve syndrome involves compression of the posterior interosseous nerve as it travels down the forearm. After the deep branch of the radial nerve passes through the supinator, it becomes the posterior interosseous nerve and courses along the posterior aspect of the forearm, running in the plane between the radius and ulna along the interosseous membrane. That makes the space between the radius and ulna the correct location. The other options describe regions not along the PIN’s path: the wrist/hand area between carpal and metacarpal bones, the space between ulna and carpal bones, or the space between the humerus and radius.

Posterior interosseous nerve syndrome involves compression of the posterior interosseous nerve as it travels down the forearm. After the deep branch of the radial nerve passes through the supinator, it becomes the posterior interosseous nerve and courses along the posterior aspect of the forearm, running in the plane between the radius and ulna along the interosseous membrane. That makes the space between the radius and ulna the correct location. The other options describe regions not along the PIN’s path: the wrist/hand area between carpal and metacarpal bones, the space between ulna and carpal bones, or the space between the humerus and radius.