The study with clinical direction value on anatomy and related kinematics of carpo-metacarpal ligaments of thumb

Objective To study the stabilizing role of carpo-metacarpal joint of the thumb ligaments to the joint. Methods 12 male adult fresh cadaveric hand specimens were dissected under loupe and the length, width, thickness and the maximal draw-extension length of each ligament were measured under normal neutrality status. The draw-extension length under maximal flexed position, back-extension position, adduct position and abduct position were measured. At the same time. we measured the normal distance and maximal distance of joint space under normal neutrality status. The variation of the joint space when various ligament was injuried is the focus point of this study. Results Five ligaments were dissected. Posterior oblique ligament and dorsal radial ligament are thick and tension, the first interosseous metacarpal ligament is the second, anterior oblique ligament is wide but laxity, ulnaris ligament narrow but thin. We can get the maximal joint space after the posterior oblique ligament and dorsal radial ligament cutted off at the same time. When the first interosseous metacarpal ligament was cutted off, the joint space is minor, the minimal joint space we can get when anterior oblique ligament and ulnaris ligament were cutted off at the same time. We can get a wider joint space after cutting off the posterior oblique ligament, dorsal radial ligament and the first interosseous metacarpal ligament at the same time than cutting off the anterior oblique ligament, ulnaris ligament and the first interosseous metacarpal ligament at the same time. Conclusion The posterior oblique ligament and dorsal radial ligament play an important role to stabilize the joint.