What Is the Brachial Artery and Where Is It Located?

The brachial artery is the main blood vessel supplying your upper arm, running from just below your shoulder to the crook of your elbow, where it splits into the two arteries that feed your forearm and hand. It begins as a continuation of the axillary artery at the lower border of the teres major muscle in the armpit and travels down the inner side of the arm. You interact with this artery more often than you probably realize, because it is the vessel compressed every time someone takes your blood pressure with a cuff.

The Path It Takes Through the Arm

The brachial artery starts at the lower edge of the armpit, where it picks up directly from the axillary artery. From there it runs along the medial (inner) side of the upper arm, sitting in a groove between the biceps muscle in front and the triceps behind. In the upper arm, the artery lies close to the humerus bone and is accompanied by the median nerve, which crosses over or under the artery partway down. As it descends, the artery gradually moves toward the front of the arm, making it increasingly accessible to the skin surface near the elbow. This superficial position near the elbow is why clinicians can feel its pulse easily and why it is the go-to site for blood pressure readings.

Along the way, the brachial artery gives off several branches. The most significant is the deep brachial artery, also called the profunda brachii, which is one of the principal branches and dives backward to supply the triceps and the posterior compartment of the arm.¹ Other branches include the superior and inferior ulnar collateral arteries, which help supply the elbow joint and create connections with the arteries of the forearm.

The Cubital Fossa and Its Terminal Split

The brachial artery’s journey ends at the cubital fossa, the shallow triangular depression on the front of your elbow. In this small but anatomically busy region, the brachial artery sits between the median nerve on the medial side and the biceps tendon on the lateral side. At or just below the apex of the cubital fossa, the brachial artery divides into its two terminal branches: the radial artery and the ulnar artery. These two vessels continue into the forearm and eventually supply the wrist and hand. The radial artery, running along the thumb side of the forearm, is the one you feel when you check your pulse at the wrist.

Why It Matters Every Time Your Blood Pressure Is Taken

When a clinician wraps an inflatable cuff around your upper arm, the target is the brachial artery. The cuff squeezes hard enough to temporarily block blood flow through the vessel, and as the pressure is slowly released, blood begins to push through. In a manual reading, the clinician listens with a stethoscope placed over the brachial artery at the cubital fossa for characteristic tapping sounds called Korotkoff sounds. The pressure at which those sounds first appear marks your systolic blood pressure, and the pressure at which they disappear marks your diastolic reading.

These Korotkoff sounds are fundamental to how virtually all blood pressure devices are calibrated. Even automated oscillometric monitors, the kind you find at pharmacies and in home-use devices, are validated against the Korotkoff-sound method as required by international standards.² Recent research has also explored whether listening to these sounds as the cuff inflates, rather than deflates, could improve accuracy. The rationale is that some sources of error during deflation, such as slow air release or patient movement, might be avoided. Early findings suggest that inflation-based readings tend to produce slightly higher values, though whether this brings results closer to the actual pressure inside the artery is still being studied.³

Checking a Pulse in Infants

In adults, the go-to spot for checking a pulse in an emergency is usually the carotid artery in the neck. In infants, the brachial artery takes that role. The accepted standard for determining whether an infant’s heart is beating during CPR has historically been palpation of the brachial pulse on the inner upper arm.⁴ To find it, you press gently on the inside of the baby’s upper arm, between the elbow and shoulder, where the artery sits close to the surface.

This sounds straightforward, but studies have shown that even trained healthcare professionals struggle with it. In one study, nurses and doctors attempting to palpate a brachial pulse in children on extracorporeal circulation found the task surprisingly difficult and often inaccurate.⁵ This challenge is part of why modern resuscitation guidelines have shifted emphasis away from pulse checks and toward looking for signs of life and starting compressions quickly when in doubt.

Flow-Mediated Dilation and Cardiovascular Risk

Beyond blood pressure and pulse checks, the brachial artery has become a research tool for assessing how healthy your blood vessels are. A test called flow-mediated dilation, or FMD, involves placing an ultrasound probe over the brachial artery, inflating a blood pressure cuff on the forearm for about five minutes to temporarily block flow, and then measuring how much the artery widens once the cuff is released. Healthy arteries dilate readily because their inner lining, the endothelium, releases nitric oxide in response to the rush of returning blood. A sluggish response suggests the endothelium is not functioning well.

Reduced flow-mediated dilation in the brachial artery correlates with similar dysfunction in the coronary arteries and tends to show up in people with risk factors for heart disease. Both measurements have been linked to long-term cardiovascular events.⁶ The brachial artery is convenient for this because it is close to the skin and easy to image, unlike the coronary arteries, which require catheterization. Still, the test has not become a routine clinical screening tool. Its value so far has been mainly in research settings, where it helps scientists study how various interventions or risk factors affect blood vessel health without invasive procedures.

How the Artery Adapts to Your Body

The brachial artery is not a fixed pipe. It actively remodels its diameter in response to blood flow. A study of over 1,500 adults found that the artery adjusts its size to maintain a consistent level of shear stress, the frictional force of flowing blood against the vessel wall. People with higher body mass, hypertension, or high cholesterol had proportionally larger arteries and higher blood flow, but their shear stress levels were similar to those in healthier individuals, suggesting the artery had successfully adapted.⁷ One exception was aging: older adults showed lower shear stress, consistent with remodeling that does not fully keep up. This distinction between adaptive and maladaptive remodeling is an active area of vascular research.

Anatomical Variations Are Surprisingly Common

If you picture the brachial artery as a single vessel that always follows the same route and splits neatly at the elbow, you are describing the textbook pattern. In reality, about one in five people has some variation from that standard layout.⁸ That is a substantial fraction, and it matters for anyone performing surgery, placing a catheter, or drawing blood from the arm.

The most common variant is a high bifurcation, where the brachial artery splits into the radial and ulnar arteries well above the elbow rather than at the cubital fossa. Other documented variations include the superficial brachial artery, where the vessel takes an unusually shallow course; the brachioradial artery, where the radial artery branches off early and high; and the accessory brachial artery, where a second brachial vessel runs alongside the main one. In rare cases, the brachial artery may even be absent, with the upper limb supplied through an alternative arterial pathway.⁹ These variations are usually silent and cause no symptoms. Most people who have them never know unless imaging is performed for another reason.

Occasionally, however, these variants create problems. An extra muscle head in the upper arm can compress both the brachial artery and the median nerve, potentially contributing to entrapment syndromes.¹⁰ For surgeons and interventional radiologists, an unexpected high bifurcation can complicate catheter placement or an operation that assumed the standard anatomy. Awareness of these variants through pre-procedural imaging can prevent complications during surgery or interventional radiology.

Trauma and Supracondylar Fractures in Children

Injuries to the brachial artery are a well-known concern in orthopedic trauma, especially in children. Supracondylar humerus fractures, breaks just above the elbow joint, are among the most common fractures in kids and the brachial artery runs right past the fracture site. A displaced fracture can stretch, compress, or even sever the artery.¹¹

The pattern of injury varies widely. The artery can suffer a simple contusion, where the vessel wall is bruised but intact, or it can be lacerated, clotted off, perforated, or completely transected with the cut ends trapped between bone fragments.¹² When the artery is blocked, the hand may lose its pulse, and the child’s fingers can become pale and cool. This is a surgical emergency. Without restoring blood flow promptly, the muscles of the forearm can be starved of oxygen, potentially leading to permanent contracture and loss of hand function. The clinical term for this disastrous outcome is Volkmann’s ischemic contracture, and preventing it depends on early recognition and rapid treatment.

Dialysis Access and Surgical Fistulas

For people with kidney failure who need long-term hemodialysis, the brachial artery plays a critical role as a connection point for vascular access. Dialysis requires drawing a large volume of blood out of the body and returning it quickly, and normal veins cannot handle that kind of flow. The solution is a surgically created arteriovenous fistula, or AVF, which directly connects an artery to a vein. This causes the vein to enlarge and thicken over several weeks, eventually becoming sturdy enough for repeated needle access.

Two of the three most commonly created fistulas involve the brachial artery: the brachiocephalic fistula, which connects the brachial artery to the cephalic vein, and the brachial artery-to-transposed basilic vein fistula.¹³ A modified version of the basilic vein fistula involves making an incision on the inner side of the elbow, isolating the brachial artery and basilic vein, and performing an anastomosis, a direct surgical connection, without having to transpose or reroute the vein.¹⁴ These upper-arm fistulas are typically used when the simpler wrist-level fistula between the radial artery and cephalic vein is not feasible, often because the wrist vessels are too small or have been damaged by prior access attempts.

The Brachial Artery as an Access Route for Catheter Procedures

Beyond permanent surgical fistulas, the brachial artery serves as an entry point for catheter-based procedures that target blood vessels far from the arm. When a vascular surgeon or interventional radiologist needs to open a blocked artery in the pelvis or legs, the usual approach is to thread a catheter through the femoral artery in the groin. Sometimes, though, the groin approach fails because of the angle of the blockage or the severity of the disease. In these cases, the brachial artery in the inner elbow provides an alternative route.

A study of patients with severe blockages in the aortoiliac arteries found that when femoral access failed, switching to a transbrachial approach allowed technical success in most remaining cases, bringing the overall success rate to about 93%. The procedure is not without risk at the arm site itself: complications at the brachial access point, including clot formation and pseudoaneurysm, occurred in a small number of cases and required additional intervention.¹⁵ Despite these risks, having the brachial artery as a backup access point gives proceduralists an important second option when the standard route is blocked.

Brachial Artery Aneurysms

True aneurysms of the brachial artery, where the vessel wall balloons outward while remaining structurally intact, are rare. Most aneurysms in the arm are pseudoaneurysms caused by trauma or catheter procedures rather than spontaneous ballooning. When a true brachial artery aneurysm does occur, it can be dangerous. The aneurysm may form clots inside the bulging segment, and those clots can break free and travel downstream, suddenly blocking blood flow to the forearm and hand. One reported case involved a middle-aged man whose brachial artery aneurysm caused acute limb ischemia and compartment syndrome in the forearm, both of which are surgical emergencies.¹⁶ The rarity of this condition means it can be overlooked or misdiagnosed, which delays treatment.

How the Artery Forms Before Birth

The brachial artery does not appear fully formed in the embryo. Early in development, the growing limb bud is supplied by a mesh of tiny capillaries sprouting from the aorta. Over the course of just a few embryonic stages, this mesh is selectively pruned and remodeled. Certain channels enlarge to become the major arteries, while the rest regress. The process starts near the aorta and works outward: by roughly the fifth week of development, the subclavian and axillary arteries have taken shape, and by the sixth week the brachial artery has differentiated as far as the elbow.¹⁷

This pruning-and-selection process is also why anatomical variations are so common. If slightly different capillary channels are retained or lost during remodeling, the adult pattern comes out differently. A vessel that should have regressed might persist as a superficial brachial artery, or the split into radial and ulnar arteries might happen higher up because the remodeling timeline was shifted. The high rate of brachial artery variants, roughly one in five people, reflects the complexity and variability of this embryonic process rather than any pathological event.

Brachial Artery Anatomy Across Primates

Comparing the brachial artery across primate species reveals an interesting evolutionary pattern. In humans and apes, the brachial artery divides into the radial and ulnar arteries near the elbow, and the hand is supplied by two palmar arches. In Old World monkeys, the split happens higher up the arm, roughly a third of the way above the elbow, and the hand has only one palmar arch.¹⁸ New World monkeys show a similar proximal-division pattern. The fact that the division point of the brachial artery and the number of palmar arches track with major phylogenetic groupings suggests that these features evolved alongside broader skeletal and muscular changes in the primate hand and forelimb. It also offers context for why high bifurcation variants in humans are so common: the developmental machinery for a higher split is part of our primate heritage and only needs a small nudge to resurface.