A study of the anatomic and histological properties of carpal ligaments

Objective To investigate the anatomic and histological properties of carpal ligaments. Methods 34 cadaver specimens of adult wrists were prepared, of which 32 were fixed in formalin and 2 were fresh. We dissected the specimens and observed the origination, insertion, course, spatial relationship of carpal ligaments with the radiocarpal joint capsule and neighboring relationship with each other. The width and thickness of middle segment of each carpal ligament as well as the length were measured. 8 cadaver specimens of adult wrists were dissected and encircled by paraffin wax. Partial carpal ligaments were sectioned and stained with hematoxylin and eosin. Then they were put under a light microscope for observation. Results The radioscaphoid, radioscaphocapitate and radiolunate ligaments were found to have similar tissue structures. They were composed of wavy and tendinous collagen fiber fascicles, among which a small amount of loose tissue was found to be intermingled with vessels. The radioscapholunate ligament was mainly composed of loose connective tissue with no bulky tendinous collagen fiber fascicles, few fiber fascicles but rich vessel bundles. The palmar, dorsal and proximal regions of the scapholunate interosseous ligament and the lunotriquetrum interosseous ligament had different histological properties. The difference was especially obvious in the proximal regions compared with the dorsal and palmar regions. The dorsal regions of the 2 ligaments were mainly composed of bulky and bunchy transverse collagen fiber fascicles while the palmar region was composed of oblique ones. The proximal regions of the 2 ligaments were mainly composed of fibrocartilage with no vessels or nerves. At the joining part between the radioscapholunate ligament and the scapholunate interosseous ligament, the vessel bundles of the radioscapholunate ligament were noticed to penetrate the scapholunate interosseous ligament in the palmar region. Conclusions The major ligaments of the wrist are palmar. The palmar ligaments are stronger than dorsal ligaments. Many adjacent ligaments oriented in a V- shaped configuration, which can strengthen the wrist stability. Most of the carpal ligaments are mainly composed of dense and bulky collagen fiber fascicles, but the radioscapholunate ligament is mainly composed of loose connective tissue blending with rich vessels, which fulfill the function of supplying blood. The proximal regions of the scapholunate and lunotriquetrum interosseous ligaments are mainly composed of fibrocartilage structure with no vessels among them.