What is the structure of the radiocarpal joint?

The human wrist joint is a very complex connection. It not only stabilizes the human wrist joint, but also has the ability to coordinate the movement of the wrist joint. Because of this, the wrist joint is very vulnerable to injury. The wrist joint is connected to the radiocarpal joint. However, most people do not know much about the radiocarpal joint, nor do they know what the radiocarpal joint does or what its structure is.

Radiocarpal joint structure

The radiocarpal joint is a typical elliptical joint. The articular socket is composed of the wrist joint surface at the lower end of the radius and the articular disc below the ulna, and the proximal surfaces of the scaphoid, lunate and triangular bones constitute the articular head. The joint capsule is loose and is reinforced by ligaments around it.

Physiological significance of the radiocarpal joint

The articular socket is formed by the wrist articular surface at the lower end of the radius and the underside of the articular disc, and together with the articular head formed by the proximal articular surfaces of the scaphoid, lunate and triquetrum bones, it is an elliptical joint. The joint capsule is thin and loose, attached to the edges of the articular surface and reinforced by ligaments around it. The volar and dorsal radiocarpal ligaments are located on the volar and dorsal sides of the joint, respectively. The ulnar collateral ligament connects between the ulnar styloid and the triangular bone, and the radial collateral ligament connects between the radial styloid and the navicular bone. The radiocarpal joint can perform flexion, extension, adduction, abduction and circumduction. The range of extension is smaller than that of flexion. This is because the palmar radiocarpal ligament is relatively tough, which limits the extension movement. In addition, since the radial styloid process is low, it abuts against the trapezium during abduction. Therefore, the range of abduction is smaller than that of adduction. It is composed of the articular socket formed by the wrist articular surface and articular disc of the radius and the articular head composed of the scaphoid, lunate and triquetrum of the proximal row of carpal bones. The scaphoid, lunate, and triquetrum are connected together by tough interosseous ligaments and have almost no movement, so they can be considered as one bone. The ulna is separated by the articular disc and does not participate in the radiocarpal joint, so structurally the radiocarpal joint is a single joint.

The radiocarpal joint capsule is loose anteriorly and posteriorly, and is reinforced by a series of ligaments around the joint, including the radial collateral ligament on the outside, the ulnar collateral ligament on the inside, the dorsal radiocarpal ligament on the back, and the palmar radiocarpal ligament on the front. The radiocarpal joint is a typical elliptical joint that can move about two axes. It can perform flexion and extension around the frontal axis, adduction and abduction around the sagittal axis, and rotation. The hand flexes more than it extends, and adduction more than it abduction. The radiocarpal joint and the intercarpal joint are collectively called the hand joint, which moves around two mutually perpendicular axes, with a flexion of approximately 60° to 70° and an extension of 45° on the frontal axis; and an adduction of approximately 35° to 40° and an abduction of 20° on the sagittal axis. The radiocarpal joint is one of the joints of the upper limb.

The radiocarpal joint is a typical elliptical joint, with the radial carpal joint surface and the underside of the articular disc forming the articular socket. The scaphoid, lunate and triquetrum bones are connected to each other by interosseous ligaments to form the articular head. The joint capsule is broad and loose, attached to the edge of the joint surface, and reinforced by ligaments outside the capsule. The radiocarpal joint and the intercarpal joint are collectively called the hand joint, which moves around two mutually perpendicular axes, with a flexion of approximately 60° to 70° and an extension of 45° on the frontal axis; and an adduction of approximately 35° to 40° and an abduction of 20° on the sagittal axis. In addition, it can also perform circular motion. Sprains and bruises are common in this joint.