depression that receives the elecranon process 3

DEPRESSION THAT RECEIVES THE ELECRANON PROCESS 3 SERIES

The head of the ulna points downward and serves as an articulating surface for the radius in a groove called the ulnar notch. Īt the distal end, the ulna consists of two protrusions – the ulnar head and the styloid process. The medial surface of the ulna only serves as an additional origin site to the flexor digitorum profundus. However, more distally, it also is involved in attachments of the extensor carpi ulnaris, supinator, abductor pollicis longus, extensor pollicis longus, and the extensor indicis propius. The dorsal surface consists of the posterior and the lateral sides of the bone and houses the insertion sites for the anconeus muscle and the supinator. Here, a system of blood vessels enters to span the shaft of the bone by extending into the medullary cavity. Between the upper and the middle third of the ulna, an opening termed the nutrient canal, is present. The volar or anterior surface of the ulna covers more area proximally than distally and allows for the origin of the flexor digitorum profundus and the pronator quadratus. The interosseous crest starts at the radial notch and then ends at the ulnar head, giving attachment to the interosseous membrane, a compact fibrous area of connective tissue filling the space between the ulna and the radius. Here, it works as attachment sites for the flexor carpi ulnaris, extensor carpi ulnaris, and the flexor digitorum profundus. The dorsal border starts posterior to the olecranon process and runs down to the styloid process as well. This border serves to be an origin site for the flexor digitorum profundus and the pronator quadratus. The volar border starts at the coronoid process and ends anterior to the styloid process.

DEPRESSION THAT RECEIVES THE ELECRANON PROCESS 3 SERIES

The body of the ulna has a series of borders and surfaces as it travels down distally. Here, the depression articulates with the humeral trochlea. The semilunar notch is another depression, formed as a bridge between the coronoid process and the olecranon process. This proximal radioulnar articulation plays a role in the supination and pronation of the forearm allowing the radial head to rotate relative to the proximal ulna. Lateral to the coronoid process, a narrow depression serves as an articulating surface for the head of the radius, called the radial notch. The most medial portion of the coronoid process is referred to as the sublime tubercle and serves as the attachment side to the anterior bundle of the medial ulnar collateral ligament. At this point, the surfaces of the coronoid process allow for the insertion of the brachialis. It slightly arches upward and fits into the coronoid fossa of the humerus.

The coronoid process is a protrusion from the proximal and anterior side of the ulna. Together, the olecranon and olecranon fossa are involved in the extension/flexion of the forearm while simultaneously preventing hyperextension. The articular surface of the proximal ulna is a notch in the olecranon along the volar surface this forms the 'hinged' ulnohumeral component of the elbow joint. This trait allows the bone to fit into the olecranon fossa of the humerus. It is a thick, curved distinction at the proximal and posterior end and is bent forward. Structure and Functionīeginning with the sites around the elbow, the ulna has a bony process called the olecranon process. Common pathologies are also associated with the bone as several fractures are pathognomonic depending on the location within the ulna, as well as the resulting position of the fractured segments. It serves as the origin and/or insertion site for more than a dozen muscles and is involved in motions assisted by the elbow and the wrist joints. In comparison to the radius, the ulna is described to be larger and longer. The bone spans from the elbow to the wrist on the medial side of the forearm when in anatomical position. The ulna is one of the two forearm long bones that, in conjunction with the radius, make up the antebrachium.

Depression that receives the elecranon process 3