Anatomy

The lateral and medial collateral ligaments provide joint stability. The nearby annular ligament attaches to the anterior and posterior margins of the radial notch on the ulna and forms a collar around the radial head.

Muscles

Elbow flexion results from the actions of the biceps brachii, brachialis, brachioradialis and pronator teres muscles, which cross the joint anteriorly. The triceps brachii inserts into the olecranon process posteriorly and together with the anconeus muscle is responsible for elbow extension.

Fig 1: Muscles for elbow flexion	Fig 2: Muscles for elbow extension

Several muscles responsible for wrist and finger flexion have a common insertion into the medial epicondyle (flexor carpi radialis, palmaris longus, flexor carpi ulnaris and flexor digitorum superficialis). Similarly, several extensor muscles insert into the lateral epicondyle (extensor carpi radialis brevis, extensor digitorum, extensor digiti minimi and extensor carpi ulnaris).

Learning bite

Several forearm flexor and extensor muscles insert at the elbow.

Nerves and arteries

The cubital fossa is a triangular depression found anterior to the elbow joint and contains the median nerve, biceps tendon, brachial artery and radial nerve (deep and superficial branches). The ulnar nerve crosses the elbow joint posteriorly, running behind the medial epicondyle in a groove adjacent to the olecranon. The olecranon bursa is located over the posterior aspect of the olecranon.