carpal tunnel syndrome. 1  a medical condition that is characterized by pain, numbness, etc. in the wrist, palm, fingers, and thumb, usually caused by repetitive hand movement, as in typing or knitting, which swells the tissue surrounding the nerve in a tunnel-like passage (carpal tunnel) in the wrist.
1 The radius is located laterally, nearer the thumb, and the ulna medially, nearer the little finger.The radius and the ulna have a styloid process at the distal end and are attachment sites for many muscles.  The radius is smaller than the ulna.
At the lower articulation of the radius and ulna, the distal radioulnar joint, the adjoining surfaces are the opposite of those on the proximal joint: the cylindrical head of the ulna meets with the ulnar notch on the bottom of the radius.d. The movement allowed at the proximal radioulnar joint is supination, or rotation of the forearm palm-up. To make this movement possible, the muscles responsible, the biceps brachii in the upper arm and the supinator in the forearm, attach to the radius and pull on it during contraction.