Cubital fossa !

The cubital fossa is the hollow at the front of the elbow; the main artery and a major nerve of the arm pass through it, under the veins used for blood draws.

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What it is

A triangle at the front of the elbow: above, a line between the epicondyles; outside, brachioradialis; inside, pronator teres. Brachialis and supinator form the floor; the bicipital aponeurosis and skin with the median cubital vein form the roof.

What it does

Lets the main structures pass the elbow. From inside to outside: median nerve, brachial artery, biceps tendon, and the radial nerve just under the edge of brachioradialis. The brachial artery divides into the radial and ulnar arteries here.

Key facts

Where: Front of the elbow; base: line between the epicondyles; lateral: brachioradialis; medial: pronator teres
Attaches: Floor: brachialis and supinator; roof: deep fascia, bicipital aponeurosis, median cubital vein in the superficial fascia
Function: Contents medial to lateral: median nerve, brachial artery (divides into radial and ulnar arteries), biceps tendon, radial nerve (under brachioradialis)

Relations

Superficial: Skin of the elbow crease and superficial fascia with the median cubital vein (or an M of median cephalic and median basilic veins) and branches of the forearm skin nerves; then the bicipital aponeurosis
Deep: Floor of brachialis above and supinator below, lying on the elbow capsule; the brachialis keeps the vessels off the joint
Medial: Medial bicipital groove, between the biceps tendon and the pronator teres: deep, the brachial artery with its veins and the median nerve; superficial, the median basilic vein and the medial forearm skin nerve
Lateral: Lateral bicipital groove, between the biceps tendon and the brachioradialis: deep, the radial nerve dividing into its two branches, with the radial collateral and radial recurrent arteries; superficial, the median cephalic vein and the lateral forearm skin nerve
Below: Apex where brachioradialis meets pronator teres: the radial artery continues under brachioradialis, the ulnar artery passes deep to the ulnar head of pronator teres

How to find it

With the elbow straight and the forearm supinated, the distal biceps tendon is felt as a firm cord in the middle of the crease, sharper on resisted flexion. The brachial pulse lies just medial to it and the median nerve about a finger-width further medial. The crease sits a little below the line joining the epicondyles.

On imaging

Ultrasound across the crease shows, from lateral to medial, the biceps tendon, the brachial artery with its paired veins and the median nerve lying on brachialis; it guides difficult venous access and median nerve blocks. In children, a raised anterior fat pad on a lateral elbow X-ray suggests a supracondylar fracture.

Common problems

Blood draws and IV lines go into the median cubital vein in its roof; the bicipital aponeurosis shields the artery and nerve below.
The blood pressure cuff's stethoscope goes over the brachial artery here.
A displaced supracondylar fracture in a child can injure the brachial artery or the median nerve.

Clinical notes

A needle pushed too deep or too medial during a blood draw can reach the brachial artery or the median nerve
A superficial artery from a high division of the brachial artery can run over the bicipital aponeurosis and be entered by mistake; injecting irritant drugs into it can cause severe hand ischaemia
Median nerve block at the elbow: the nerve is found just medial to the brachial artery at the level of the intercondylar line
Swelling or a tight cast after a supracondylar fracture can compress the brachial artery here, leading to forearm compartment syndrome and Volkmann ischaemic contracture

Anatomical variants

Superficial venous pattern varies: a single oblique median cubital vein, or an M formed by median cephalic and median basilic veins (the classic textbook pattern)
High division of the brachial artery: the radial or ulnar artery can arise in the arm and cross the fossa superficially

Memory aid

TAN from lateral to medial: Tendon (biceps), Artery (brachial), Nerve (median); the radial nerve hides further lateral under the brachioradialis.

Test yourself

Think of the answer, then tap the question to see it.

What forms the floor of the cubital fossa?

The brachialis above and the supinator below, lying on the elbow capsule.

Which structure separates the median cubital vein from the brachial artery?

The bicipital aponeurosis, which also covers the median nerve.

How does the median nerve leave the cubital fossa?

Between the humeral and ulnar heads of the pronator teres.

Which artery and nerve are at risk in an extension-type supracondylar fracture?

The brachial artery and the median nerve, especially its anterior interosseous branch, pushed by the proximal fragment.

What runs deep in the lateral bicipital groove?

The radial nerve, dividing into superficial and deep branches, with the radial collateral–radial recurrent anastomosis.

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Educational information, not medical advice. For any symptom, see a health professional.

Its names

Official Latin (TA2): fossa cubitalis TA2 291
Official Spanish (DeCS): Fosa cubital
English (TA2): Cubital fossa
Also called: antecubital fossa · elbow pit

Sources: Terminologia Anatomica (TA2); Anatomía humana (4.ª ed.), tomo 1, cap. 56: Articulación del codo. Músculos del brazo; Anatomía humana (4.ª ed.), tomo 1, cap. 57: Antebrazo. Aparato de la pronosupinación.

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