Cubital fossa

The cubital fossa (a.k.a. the antecubital fossa) is a crucial triangular depression located on the anterior aspect of the elbow.

Its boundaries are defined as follows:

• Laterally: The medial border of the brachioradialis muscle.

• Medially: The lateral border of the pronator teres muscle.

• Superiorly (base): An imaginary line connecting the medial and lateral epicondyles of the humerus.

• The floor of the fossa is formed by the brachialis and the supinator muscles.

• The roof is composed of several layers: skin, superficial fascia (which typically contains the prominent median cubital vein, a common site for venipuncture), and the bicipital aponeurosis.

The contents of the cubital fossa, arranged from lateral to medial, are:

• The tendon of the biceps brachii.

• The brachial artery, which commonly bifurcates into its terminal branches, the radial and ulnar arteries, within the confines of the fossa.

• The median nerve.

It is important to note that the radial nerve passes just lateral to the cubital fossa, deep to the brachioradialis muscle, where it typically divides into its superficial (sensory) and deep (posterior interosseous) branches. Additionally, the lateral antebrachial cutaneous nerve (also known as the lateral cutaneous nerve of the forearm) emerges laterally to the biceps tendon in this region, making it susceptible to injury during clinical procedures.

The clinical significance of the cubital fossa is paramount, particularly due to the superficial and accessible location of the median cubital vein, making it the preferred site for routine venipuncture.