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The olecranon is a large, thick, curved eminence, situated at the upper and back part of the ulna. It is bent forward at the summit so as to present a prominent lip which is received into the olecranon fossa of the humerus in extension of the forearm. Its base is contracted where it joins the body and the narrowest part of the upper end of the ...
Schematic diagram of the medial side of the elbow showing the ulnar nerve passing through the cubital tunnel. Chronic compression of the ulnar nerve in the cubital tunnel is known as cubital tunnel syndrome. [4] There are several sites of possible compression, traction or friction of the ulnar nerve as it courses behind the elbow. [5]
The ulnar nerve originates from the C8-T1 nerve roots (and occasionally carries C7 fibers which arise from the lateral cord), [5] [6] which then form part of the medial cord of the brachial plexus, and descends medial to the brachial artery, up until the insertion point of coracobrachialis muscle (middle 5 cm over the medial border of the humerus).
The ulnar nerve is also in the area, but is not in the cubital fossa; it occupies a groove on the posterior aspect of the medial epicondyle of the humerus. Several veins are also in the area (for example, the median cubital vein , cephalic vein , and basilic vein ) but these are usually considered superficial to the cubital fossa, and not part ...
At the junction of this surface with the front of the body is a rough eminence, the tuberosity of the ulna, which gives insertion to a part of the brachialis; to the lateral border of this tuberosity the oblique cord is attached. Its lateral surface presents a narrow, oblong, articular depression, the radial notch.
The styloid process of the ulna projects from the medial and back part of the ulna. It descends a little lower than the head. The head is separated from the styloid process by a depression for the attachment of the apex of the triangular articular disk, and behind, by a shallow groove for the tendon of the extensor carpi ulnaris muscle.
When the forearm is extended and supinated, the axis of the arm and forearm are not in the same line; the arm forms an obtuse angle with the forearm, known as the carrying angle. During flexion, however, the forearm and the hand tend to approach the middle line of the body, and thus enable the hand to be easily carried to the face.
It supplies sensory innervation to a small area in the palmar surface of the wrist. The palmar branch represents the continuation of the ulnar nerve as it crosses the flexor retinaculum of the hand on the lateral side of the pisiform bone, medial to and a little behind the ulnar artery .