The Wrist Joint Flashcards
What type of joint is the wrist joint?
A synovial joint
What are the distal articulating surfaces of the wrist joint ?
The proximal row of the carpal bones (except the pisiform). So the proximal row includes the scaphoid, lunate and triquetrum.
What are the proximal articulating surfaces of the wrist joint?
The distal end of the radius and the articular disk
Why is the ulna not part of the wrist joint?
The ulna articulates with the radius, just proximal to the wrist joint, at the distal radioulnar joint. It is prevented from articulating with the carpal bones by a fibrocartilaginous ligament called the articular disk, which lies over the superior surface of the ulna.
What type of surface do the carpal bones form altogether?
Together, the carpal bones form a convex surface, which articulates with the concave surface of the radius and articular disk.
Outline the blood supply to the wrist joint.
The wrist joint receives blood from branches of the dorsal and palmar carpal arches, which are derived from the ulnar and radial arteries.
Outline the innervation to the wrist joint.
Innervation to the wrist is delivered by branches of three nerves:
Median nerve - anterior interosseous branch
Radial nerve - posterior interosseous branch
Ulnar nerve - deep and dorsal branches
What contributes to the stability of the wrist joint?
The joint capsule and ligaments contribute to the stability of the wrist joint.
How does the joint capsule contribute to the stability of the wrist joint?
Like any synovial joint, the capsule is dual layered. The fibrous outer layer attaches to the radius, ulna and the proximal row of the carpal bones. The internal layer is comprised of a synovial membrane, secreting synovial fluid which lubricates the joint.
How many ligaments are there in the wrist joint?
4 - one for each side of the joint
Name the ligaments of the wrist joint
Palmar radiocarpal
Dorsal radiocarpal
Ulnar collateral
Radial collateral
Where is the palmar radiocarpal ligament found and what is its function?
It is found on the palmar (anterior) side of the hand. It passes from the radius to both rows of carpal bones.
Its function, apart from increasing stability, is to ensure that the hand follows the forearm during supination.
Where is the dorsal radiocarpal ligament found and what is its function?
It is found on the dorsal (posterior) side of the hand. It passes from the radius to both rows of carpal bones. It contributes to the stability of the wrist, but also ensures that the hand follows the forearm during pronation.
Where is the ulnar collateral ligament found and what is its function?
Runs from the ulnar styloid process to the triquetrum and pisiform. Works in union with the other collateral ligament to prevent excessive lateral joint displacement
Where is the radial collateral ligament found and what is its function?
Runs from the radial styloid process to the scaphoid and trapezium. Works in union with the other collateral ligament to prevent excessive lateral joint displacement.
