FLEXOR CARPI RADIALIS TENDINITIS .1. OPERATIVE ANATOMY

The anatomical characteristics of the flexor carpi radialis tendon, th e tendon sheath, the tunnel boundaries, and the adjacent structures we re examined in twenty-five adult cadaveric specimens. Transverse and s agittal sections of the wrist and forearm, tenograms, and histological sections of the tendon were made from two additional specimens each. The musculotendinous portion of the flexor carpi radialis tendon begin s an average of fifteen centimeters (range, twelve to seventeen centim eters) proximal to the radiocarpal joint; the muscular fibers end an a verage of eight centimeters (range, six to nine centimeters) proximal to the wrist. The synovial sheath extends from the origin to the inser tion. The tendon enters a fibro-osseous tunnel at the proximal border of the trapezium and is separated from the carpal canal by a thick sep tum that functions, at its distal border, as a pivot point for the fle xor pollicis longus. Within the tunnel, the tendon occupies 90 per cen t of the available space and is in direct contact with the slightly ro ughened surface of the trapezium. The tendon lies within a few millime ters of the distal aspect of the radius, the scaphoid tubercle, the sc aphoid-trapezium-trapezoid joint, and the carpometacarpal joint of the thumb. In most patients, the flexor carpi radialis tendon is inserted at three locations. A small slip is connected to the trapezial crest or tuberosity; 80 per cent of the remaining tendon is inserted on the base of the second metacarpal and 20 per cent, on the base of the thir d metacarpal. The deep palmar arch is located two to three millimeters distal to insertion of the tendon.