Search results
Results From The WOW.Com Content Network
The humeroulnar joint (ulnohumeral or trochlear joint [1]) is part of the elbow-joint. It is composed of two bones, the humerus and ulna, and is the junction between the trochlear notch of ulna and the trochlea of humerus. [1] It is classified as a simple hinge-joint, which allows for movements of flexion, extension and circumduction.
Therefore, the humeroradial joint is not functionally a ball and socket joint, although the joint surface in itself allows movement in all directions. The annular ligament secures the head of the radius from dislocation, which would otherwise tend to occur, from the shallowness of the cup-like surface on the head of the radius.
Joint From To Description Humeroulnar joint: trochlear notch of the ulna: trochlea of humerus: Is a simple hinge-joint, and allows for movements of flexion and extension only. Humeroradial joint: head of the radius: capitulum of the humerus: Is a ball-and-socket joint. Proximal radioulnar joint: head of the radius: radial notch of the ulna
The elbow joint is a complex of three joints — the humeroradial, humeroulnar, and superior radioulnar joints — the former two allowing flexion and extension whilst the latter, together with its inferior namesake, allows supination and pronation at the wrist.
Joints of the hand, X-ray. The bones in each carpal row interlock with each other and each row can therefore be considered a single joint. In the proximal row a limited degree of mobility is possible, but the bones of the distal row are connected to each other and to the metacarpal bones by strong ligaments that make this row and the metacarpus a functional entity.
It consists of two portions, an anterior and posterior united by a thinner intermediate portion. Note that this ligament is also referred to as the medial collateral ligament [1] and should not be confused with the lateral ulnar collateral ligament (LUCL).
The ligaments may be best seen by opening the capsule at the back of the joint and removing the head of the humerus: [2]. One on the medial side of the joint passes from the medial edge of the glenoid cavity to the lower part of the lesser tubercle of the humerus.
The head of the radius has a cylindrical form, and on its upper surface is a shallow cup or fovea for articulation with the capitulum of the humerus.The circumference of the head is smooth; it is broad medially where it articulates with the radial notch of the ulna, narrow in the rest of its extent, which is embraced by the annular ligament.