basisgewricht

Basisgewricht, also known as the carpometacarpal joint of the thumb, is a saddle joint located at the base of the thumb. It is formed by the articulation of the trapezium bone of the wrist with the first metacarpal bone. This unique joint structure allows for a wide range of motion, enabling the thumb to oppose the other fingers, a crucial function for grasping and manipulation. The joint is surrounded by a capsule reinforced by several ligaments, including the radial and ulnar collateral ligaments, and the anterior and posterior oblique ligaments, providing stability. The synovial membrane lines the joint capsule, secreting synovial fluid that lubricates the articulating surfaces. The primary movements at the basisgewricht include flexion, extension, abduction, adduction, and circumduction. Opposition, the movement of bringing the thumb to touch the tips of the other fingers, is a complex action involving multiple muscles and is facilitated by the saddle shape of the basisgewricht. Conditions affecting this joint include osteoarthritis, which is common due to its frequent use, leading to pain, stiffness, and reduced grip strength. Other conditions include sprains, dislocations, and fractures.