What is the Brachial Artery?

The axillary artery runs through the axilla or armpit and becomes the brachial artery, which starts at the teres major muscle on the underside of the upper arm between the elbow and shoulder and ends at the cubital fossa on the inner elbow. From there, it divides into the ulnar artery and radial artery, which run along the two bones of the forearm.

The brachial artery and its branches are the main blood supply for the arm from the axilla to the hand. The vessel feeds the biceps directly, while the triceps and deltoid muscles receive blood from the profunda brachii or deep brachial artery, which branches off, as do the ulnar and radial arteries.

Oxygenated blood leaves the heart and circulates through the body, delivering oxygen and nutrients to the cells. From there, it travels through the veins, back to the right side of the heart, and into the lungs where it is reoxygenated before being pumped back into the body. The brachial artery is responsible for supplying all the cells in the arm with the oxygen and nutrients they need.

The brachial artery is close to the surface and lays so close to the humerus in the upper arm and the elbow that there is a significant risk for damage when a person endures a fracture or other trauma. Healthcare professionals take great care when assessing these injuries to make sure there is no damage to the vessel.

Most people have typical brachial arteries, but there are some exceptions. About 20 percent of the population has completely or partially duplicated brachial arteries. Another possible difference is a superficial brachial artery that runs anteriorly to the median nerve in the upper arm, instead of behind it.

Some surgical procedures involve creating a fistula, which establishes a direct connection between an artery and a vein to prepare for hemodialysis. This treatment for people with kidney disease filters impurities out of the blood when the kidneys do not work properly. The fistula is usually formed between the brachial artery and vein to create an access point for the artificial kidney or dialysis machine.

Technicians and nurses always take common lab draws from a vein, not an artery. When a tourniquet is applied to the upper arm, blood backs up into the vein, making it easier to feel. One exception is an arterial blood gas, a special blood test typically only performed in hospitals, by a doctor, on patients with critical heart or lung problems. It measures oxygen and other values that indicate how well the blood is oxygenating.

Because the brachial artery is close to the surface, healthcare providers use it to assess blood pressure. The cuff goes around the upper arm and is inflated while the bell of a stethoscope sits directly on the brachial artery. The practitioner determines the reading by listening for a knocking sound while looking at the sphygmomanometer.

Medical practitioners expect a small difference in blood pressure between one arm and the other, but any reading with a difference of more than ten can signal trouble. For people who consistently register different readings, this could indicate a blocked artery, diabetes, vascular disease, kidney disease, or even a heart defect.

Medical professionals commonly check the pulse of adults with the carotid artery in the neck. Infants have very short necks, which can make the carotid pulse difficult to locate, so many doctors use the brachial artery instead. This method is taught to healthcare professionals receiving advanced cardiac life support certification as well as in basic CPR classes.