![]() 419) includes two substantial processes, named the olecranon and the coronoid process, and two articular areas, termed the trochlear (semilunar) and radial notches, which articulate, respectively, with the humerus and the radius. ![]() The shaft is triangular on section, and no difficulty will be experienced in determining its three surfaces and their limiting borders. The bone diminishes in size from its upper to its lower end, which bears a small, rounded enlargement, termed the head of the ulna. This information is sufficient to enable the student to refer a given ulna to its correct side of the body. The lateral border of the shaft forms a thin, sharp crest. 419), the concavity of the hook being directed forwards. The upper end is thick, strong and hook like (fig. Galezzi's fracture-fracture to the distal radius accompanied by ulnar head dislocation at distal radio-ulna joint.General features ~The ulna is the medial bone of the forearm and is parallel to the radius when the forearm is supine.Hume fracture - fracture of the olecranon accompanied by anterior dislocation of the radial head.Monteggia fracture - fracture of the proximal 1/3 of the ulnar shaft accompanied by the dislocation of the radial head.Typically occur as a result of fragility and normally following a fall such as a fall on an outstretched hand (FOOSH) Like any other joint in the body the ulna can be affected by osteoarthritis in the elbow joint. Pronator teres - originates medial surface, also from humeral medial epicondyleįlexor Digitorum Superficialis - originates medial surface, also from humeral medial epicondyleĪll of the following arise from the shaft of the ulna:Įxtensor carpi ulnaris - also shared with lateral epicondyle of humerusĪbductor pollicis longus - also originates from interosseous membraneĮxtensor Pollicis Longus - also originates from interosseous membraneĮxtensor indicis - also originates from interosseous membraneĬlinical relevance įlexor Carpi Ulnaris - origin:posterior, also shares an origin from humeral medial epicondyleīrachialis - inserts to anterior, inferior coronoid process Triceps - inserts onto the posterior of the olecranon process. This also acts to compartmentalise dorsal and volar sides of the forearm. Which runs the length of the shaft of the ulna from the radial notch proximally to the head of the ulna. The ulna also articulates with the radius in a syndesmosis joint via its interosseous membrane. The ulna articulates with the radius proximally and distally to produce pronation (from the proximal joint) and supination (from the distal joint) of the forearm. ![]() It is the trochlea of the humerus which sits in the semi-lunar notch of the ulna to form this joint. The ulna articulates with the humerus at its most proximal point forming the elbow in a hinge joint. The styloid process has attachment of ulnar collateral ligament.Īrticulations Elbow The head of Ulna has convex articular surface on its lateral side inorder to articulate with ulnar notch of radius.It forms the distal radio-ulnar joint. It's width is decreased as it moves towards distal end. The shaft of ulna is triangular in shape and it consists of three borders and three surfaces. ![]() It articulates with the ulnar notch on the radius and with the triangular articular disc in the Wrist Joint. The lateral, distal end of the ulna is the head of the ulna. On the lateral side of the coronoid process is the radial notch where the head of the radius sits. The coronoid process also forms the lower part of the semi-lunar notch. It is received into the coronoid fossa of the humerus in elbow flexion. The coronoid process is a horizontal, bony projection which attaches directly onto the ulnar shaft. The olecranon forms the upper part of the semi-lunar notch which is a smooth, large depression and articulates with the humeral trochlea during elbow flexion and extension. This is a large, curved bony prominence which is accepted into the olecranon fossa, located on the humerus, during elbow extension. Image: Overview of the radius and ulna (anterior and posterior views) Olecranon The articulation is formed of the olecranon and the coronoid process. The proximal ulna is hook-like in form which articulates with the trochlea of the humerus to create the hinge joint of the Elbow. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |