Elbow bone

Elbow, ulna, long. In her, the body and two epiphyses are distinguished - proximal and distal. The body of the ulna, corpus ulnae, trihedral shape. It has three edges: anterior (palmar), posterior (dorsal) and interosseous (external) - and three surfaces.

The structure of the ulna.

Anterior margin, margo anterior, rounded; Posterior edge, margo posterior, directed posteriorly, and interosseous margin, margo interosseus, pointed and directed towards the radius.

The front surface, facies anterior, is somewhat concave. On it is a nutritional hole, foramen nutricium, which leads to the proximally directed nutrient canal, canalis nutricius. In the upper part of the anterior surface, on the boundary between the body and the upper end of the bone, there is a tuberosity of the ulna, tuberositas ulnae. The posterior surface, facies posterior, is turned back, and the medial surface, facies medialis, - towards the inner edge of the forearm.

The upper , or proximal, epiphysis, epiphysis proximalis, is thickened, continuing upward in the ulnar process, olecranon. The anterior surface of this appendage is occupied by a block-shaped incision, incisura trochlearis, which from below is restricted by the coronoid processus, processus coronoideus. On the outer surface of the coronoid process there is a radial incision, incisura radialis, the place of articulation of the ulna with the articular circumference of the radial head. Behind the radial notch begins the comb of the instep. Crista m. Supinatoris, which, following down, reaches the upper parts of the body of the bone.

Lower , or distal, epiphysis, epiphysis distalis, ulna is rounded. It distinguishes the head of the ulna, caput ulnae. The surface of the head, facing the wrist, is smooth and concave. On the periphery of the head is the joint surface, - articular circumference, circumferentia articularis, ulna, articulating with the radius. The medial posterior surface of the head extends into the styloid process, processus styloideus; It is well probed through the skin. The ulnar joint is read here .