Cubital Fossa

fossa cubitalis

The cubital fossa is the triangular anterior elbow depression bounded medially by pronator teres, laterally by brachioradialis, and superiorly by an imaginary line between the epicondyles. Its floor is brachialis (medially) and supinator (laterally). Contents from medial to lateral: median nerve, brachial artery (and its bifurcation), biceps tendon, and the radial nerve. The lacertus fibrosus (bicipital aponeurosis) covers the fossa.

Region: Forearm

Clinical Relevance

Clinical Notes

The cubital fossa is the site of antecubital venepuncture and blood pressure auscultation (brachial artery Korotkoff sounds). The biceps tendon in the cubital fossa can be palpated and is the tendon injured in distal biceps rupture, presenting as a palpable gap and weakness of supination. The lacertus fibrosus can entrap the median nerve (lacertus fibrosus compression syndrome) producing a proximal median neuropathy with Tinel at the medial cubital fossa. The radial nerve in the lateral cubital fossa divides into superficial and posterior interosseous branches.

Pathology

Common Injuries & Conditions

Distal Biceps Tendon Rupture in Cubital Fossa

Eccentric load on the flexed elbow ruptures the distal biceps tendon at the radial tuberosity, producing an audible pop, anterior elbow bruising, weakness of supination and flexion, and a palpable gap in the cubital fossa when the tendon retracts into the arm; repaired urgently by anatomic reattachment to the radial tuberosity.