Brachial artery: where it runs, its branches and the brachial pulse

What it is

The brachial artery is the main artery of the arm, continuing the axillary artery.

Location

It begins at the lower border of teres major, runs down the medial arm and into the cubital fossa, where it lies under the bicipital aponeurosis, and divides into radial and ulnar arteries at about the neck of the radius. Its branches are the deep brachial, superior and inferior ulnar collateral, and muscular arteries.

Function

It supplies the arm muscles and the humerus and provides the forearm and hand arteries.

Body system

Cardiovascular · paired (left and right)

FMA ID

FMA22692 (Foundational Model of Anatomy)

Key facts

• Its pulse is felt medial to the biceps tendon and is used in blood pressure measurement.
• The median nerve crosses it from lateral to medial in the middle of the arm.

Clinical relevance

A supracondylar fracture of the humerus can damage it.

The brachial artery continues the axillary artery. Its name changes at the lower border of the teres major tendon, at the bottom of the back wall of the armpit. It ends about 1 cm below the elbow joint, level with the neck of the radius, by dividing into the radial and ulnar arteries. (Kenhub: Brachial artery.)

In the upper arm it lies on the medial (inner) side of the humerus, medial to biceps brachii and in front of the medial head of triceps. As it approaches the elbow it moves forwards to lie in front of the humerus, passes under the bicipital aponeurosis (lacertus fibrosus) and enters the cubital fossa. (Radiopaedia: Brachial artery.)

For most of its length it is superficial, covered only by skin and fascia. That is why its pulse can be felt, and why it can be compressed against the humerus along the inner arm. (Kenhub: Brachial artery.)

OpenStax summarises its place in the circulation: the subclavian artery becomes the axillary artery as it enters the axillary region, the vessel continues into the upper arm (brachium) as the brachial artery, and the brachial artery divides into the radial and ulnar arteries near the elbow. (OpenStax Anatomy and Physiology 2e, 20.5: Circulatory Pathways.)

The median nerve is the brachial artery's closest companion. High in the arm the nerve and coracobrachialis lie lateral to the artery; near the lower attachment of coracobrachialis the nerve crosses in front of the artery; lower down the median nerve lies medial to it. The ulnar nerve and the medial antebrachial cutaneous nerve lie medial to the upper part of the artery. (Kenhub: Brachial artery.)

Behind the artery, from above down, are the long head of triceps (separated from it by the radial nerve and the profunda brachii artery), the medial head of triceps and the attachments of coracobrachialis and brachialis. Two deep veins, the venae comitantes, run on either side of it and are joined by small cross-branches; the basilic vein lies on its medial side. (Kenhub: Brachial artery.)

In the cubital fossa the contents from lateral to medial are the radial nerve, the biceps tendon, the brachial artery and the median nerve. The floor is brachialis above and supinator below. (TeachMeAnatomy: The Cubital Fossa.)

The median cubital vein crosses the roof of the fossa superficial to the artery. The bicipital aponeurosis lies between them, which gives some protection to the artery and the median nerve during blood tests from this vein. (TeachMeAnatomy: Median Cubital Vein.)

The profunda brachii (deep brachial) artery is the first and largest branch. It arises from the posteromedial side of the brachial artery just below teres major, passes with the radial nerve through the triangular interval into the back of the arm and runs in the radial groove of the humerus between the medial and lateral heads of triceps. It mainly supplies triceps and ends as the middle collateral and radial collateral arteries. (Radiopaedia: Profunda brachii artery.)

Below the profunda brachii the brachial artery gives nutrient arteries to the humerus, then the superior and inferior ulnar collateral arteries on its medial side near the elbow, and many small muscular branches to the front of the arm. (Radiopaedia: Brachial artery.)

The superior ulnar collateral artery passes into the posterior compartment and supplies the medial head of triceps. The inferior ulnar collateral (supratrochlear) artery arises about 5 cm above the elbow and winds round the humerus. (Kenhub: Brachial artery.)

The two terminal branches are the radial artery, which gives the radial recurrent artery, and the ulnar artery, the larger of the two, which gives the ulnar recurrent arteries and the common interosseous artery. (Kenhub: Brachial artery.)

The whole arterial chain from subclavian to palmar arches, and the veins of the arm and hand. Arteries and veins of the arm.

Branches above and below the elbow join to form a network round the joint. The inferior ulnar collateral artery meets the middle collateral branch of the profunda brachii to form an arch above the olecranon fossa. The superior and inferior ulnar collateral arteries join the anterior and posterior ulnar recurrent arteries, and the radial recurrent artery joins the radial collateral branch of the profunda brachii. (Kenhub: Brachial artery.)

This network is why the level of a blockage matters. Occlusion of the brachial artery above the origin of the profunda brachii is likely to cause severe ischaemia of the limb, while occlusion below it is usually less disabling because blood can bypass the block through the elbow collaterals. (Radiopaedia: Brachial artery.)

The brachial pulse can be felt along the medial side of biceps brachii in the arm and, most usefully, in the cubital fossa just medial to the biceps tendon. Kenhub notes that the pulse cannot be felt once the artery has passed under the bicipital aponeurosis. (Kenhub: Brachial artery.)

Measuring blood pressure by hand uses a sphygmomanometer: an inflatable cuff wrapped around the arm at about heart level and a stethoscope placed over the brachial artery at the front of the elbow. As the cuff is let down, turbulent flow through the artery makes soft tapping noises called Korotkoff sounds. (OpenStax Anatomy and Physiology 2e, 20.2: Blood Flow, Blood Pressure, and Resistance.)

The first Korotkoff sound marks the systolic pressure, typically about 120 mm Hg, and the point at which the last sound is heard marks the diastolic pressure, usually about 80 mm Hg. (OpenStax Anatomy and Physiology 2e, 20.2: Blood Flow, Blood Pressure, and Resistance.)

Kenhub describes the routine: the cuff is inflated to 20 to 30 mm Hg above the expected systolic pressure, then let down slowly while the examiner listens with the stethoscope over the brachial artery in the cubital fossa. (Kenhub: Brachial artery.)

Because the brachial artery is so superficial, it is also a common route for catheters: Radiopaedia lists it as a vascular access site for some procedures and notes its role in radial-approach angiography. (Radiopaedia: Brachial artery.)

The most common variant is a high bifurcation, in which the brachial artery divides into the radial and ulnar arteries in the arm or even the axilla instead of at the elbow. A 2020 review gives an overall incidence of about 8%, and a superficial brachial artery, one that runs in front of rather than behind the median nerve, in about 3.6% to 9.6% of people. (Tsoucalas G et al. High Bifurcation of the Brachial Artery: An Embryological Overview. Cureus. 2020.)

Figures differ between studies. In one dissection series of 42 upper limbs, the brachial artery divided high in three (7.1%). The authors warn that unusual multiple branching of the brachial artery in the cubital fossa could seriously compromise the blood supply of the forearm. (Sophia L et al. Upper limb arterial pattern: clinical correlation and embryological perspective. J Vasc Bras. 2021.)

High bifurcation is not just a curiosity: it is linked with higher failure rates of arteriovenous fistulas for dialysis, it can cause confusion during angiography, and it can complicate flap surgery and repair of the distal biceps tendon. (Tsoucalas G et al. High Bifurcation of the Brachial Artery: An Embryological Overview. Cureus. 2020.)

In the embryo each upper limb is supplied by an axis artery that grows out from the seventh intersegmental (future subclavian) artery. Its main trunk becomes the axillary and brachial arteries, and parts of it persist as the anterior interosseous artery and the deep palmar arch; variants arise when other early channels persist or regress differently. (Tsoucalas G et al. High Bifurcation of the Brachial Artery: An Embryological Overview. Cureus. 2020.)

A supracondylar fracture of the humerus, most often in children who fall on an outstretched hand, can damage the brachial artery directly or through swelling in the cubital fossa. If damage to the artery is not repaired, Volkmann's ischaemic contracture can follow. (TeachMeAnatomy: The Cubital Fossa.)

Volkmann's ischaemic contracture is a flexion deformity of the wrist and fingers: forearm muscles that lost their blood supply die and are replaced by fibrous tissue, which shortens. The anastomoses around the elbow protect the forearm from partial or brief occlusion, but not from complete occlusion or a severed artery. (TeachMeAnatomy: Arterial Supply to the Upper Limb.)

To control bleeding from the arm, pressure is applied above the wound, pressing the artery against the medial side of the humerus. Clamping the artery below the origin of the profunda brachii is said to be tolerated because the elbow collaterals keep the forearm supplied. (Kenhub: Brachial artery.)

The nearest named structures in the 3D model, measured from the centre of each part:

• Deep brachial artery · cardiovascular
• Long head of biceps brachii · muscular
• Medial head of triceps brachii · muscular
• Humerus · skeletal
• Long head of triceps brachii · muscular
• Lateral head of triceps brachii · muscular
• Brachialis · muscular
• Short head of biceps brachii · muscular
• Superior ulnar collateral artery · cardiovascular
• Middle collateral branch of deep brachial artery · cardiovascular