Abstract:

Objective　To study the anatomical characteristics of the ligaments of the carpometacarpal joint of thumb and the role of the ligaments in the thumb movement.　Methods 　20 fresh hand specimens of adult male cadavers were dissected under the magnifying glass, and the starting and ending points and attachment sites of the carpometacarpal joint of thumb. The length, width, thickness and maximum length of each ligament in the neutral position were measured. The range of the motion of the joint was also measured.　Results　There are 5 ligaments around the carpometacarpal joint of thumb. Among these ligaments, the dorsal radial ligament, posterior oblique ligament, and anterior oblique ligament are the joint capsular ligament, while the first inter-metacarpal ligament, and the ulnar ligament are the extra capsular ligament. The dorsal radial ligament is the thickest (2.08±0.27 mm), and the thinnest is the anterior oblique ligament（1.14±0.17 mm）.The anterior oblique ligament is the widest（9.33±1.09 mm）, and the narrowest is the posterior oblique ligament（7.23±0.88 mm）. The longest elongation is the dorsal radial ligament（57.33%±9.21%）, and the shortest is the anterior oblique ligament（38.43%±8.26%）.　Conclusion　The carpometacarpal joint of thumb has three stable structures. In the joint capsule and ligaments structure, the dorsal radial ligament is thickest and most tenacious. It is the main ligament to maintain the joint stability. The anterior oblique ligament is thin and loose，making it vulnerable to degenerative change when injured or spontaneously strained, which then should be reconstructed in the first place.

Key words: Thumb, Carpometacarpal joint, Ligament, Anatomy