Median artery and superficial palmar branch of the radial artery in the carpal tunnel.

In the carpal tunnel there are the flexor muscle tendons, their sheaths, and the median nerve. Because its walls are inflexible, any thickening of its components that reduce its area may compress the median nerve. There are many reasons for nerve compression, including persistence of the median artery into adult life. We dissected the arteries in the carpal tunnel of 102 hands of 51 adult cadavers of both sexes, age range 23-77 years, and injected latex into 42 hands. In the carpal tunnel we sought the median artery and the superficial palmar branch of the radial artery. We found the median artery in 23 of 102 cases (23%), and its calibre ranged from 0.7 to 2.7 mm, mean (SD) 1.6 (0.5) mm. In 16 cases it made up part of the superficial palmar arch. The superficial palmar branch of the radial artery was partly responsible for the distal irrigation of the hand in 48 cases (47%); and in three hands (3%) it passed through the carpal tunnel. The external diameters of these vessels were 1.8, 1.9, and 1.8 mm, respectively. These arteries might cause compression of the median nerve and consequently the carpal tunnel syndrome.