Anatomy and Contents of the Cubital Fossa

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

The cubital fossa is a triangular depression located in front of the anterior elbow.The medial border is formed by the pronator teres which arises from the medial epicondyle of the humerus.The lateral border is formed by the brachioradialis muscle which arises from the lateral supracondylar ridge of the humerus.The meeting of these 2 muscles forms the apex of the cubital fossa.The brachioradialis muscle overlaps the pronator teres ,so the medial border overlaps the lateral border.The base of the cubital fossa is superior and is represented by a straight line joining the 2 epicondyles of the humerus,the medial and the lateral epicondyles.

The contents of the cubital fossa from medial to lateral are median nerve(being medial most).The median nerve disappears by entering the forearm between the two heads of the pronator teres muscle.Located next lateral to the median nerve is the brachial artery which bifurcates into the radial and ulnar arteries.The brachial artery is located over the brachialis muscle.The ulnar artery leaves the fossa by going under the deep head of the pronator teres muscle.The deep head of the pronator teres muscle separates the median nerve which goes between the two heads of the pronator teres muscle from the ulnar artery which goes deep to the deep head of the pronator teres muscle.Another branch in the cubital fossa is the radial artery which descends laterally and is overlapped by the brachioradialis muscle.

The biceps tendon which lies lateral to the brachial artery within the cubital fossa has one main insertion to the radial tuberosity laterally and another insertion going medially to the bicipital aponeurosis. The bicipital aponeurosis covers and protects the vital structures medial to the biceps tendon(median nerve and brachial artery).The biceps tendon passes backwards(twisted) towards its insertion to the radial tuberosity.Lateral to the biceps tendon is the radial nerve and it’s major branch,the posterior interosseous nerve.Other important nerves in the vicinity of the cubital fossa are the superficial radial nerve(below the brachioradialis) and the lateral cutaneous nerve of forearm ,branch of the musculocutaneous nerve which lies deep to the biceps proximally and then finally it lies laterally.The floor of the cubital fossa is made up of the lower part of the brachialis muscle medially and the supinator muscle laterally.The roof of the fossa is made up of the skin,fascia and the bicipital aponeurosis.