The brachial artery is a major blood vessel located in the upper arm. It serves as the primary conduit for oxygenated blood to the entire upper limb, including the arm, forearm, and hand. This artery is an extension of the axillary artery.
Location and Role of the Brachial Artery
The brachial artery begins its course at the lower border of the teres major muscle, continuing from the axillary artery. It extends down the inner side of the upper arm, running along the front of the biceps muscle. As it descends, it moves from a position medial to the humerus bone to a more anterior location near the elbow.
The artery terminates at the cubital fossa, the indentation at the front of the elbow. At this point, it divides into two main branches: the radial and ulnar arteries, which then supply blood to the forearm, wrist, and hand. Throughout its path, the brachial artery also gives off several smaller branches, including the deep brachial artery. These branches deliver blood to various muscles in the upper arm, such as the biceps brachii, brachialis, and triceps brachii muscles, as well as the elbow joint and humerus bone. Its deep position, nestled between muscles, provides protection from external injury.
Medical Procedures Involving the Brachial Artery
The brachial artery holds significance in clinical practice due to its accessible location. It is a common site for assessing a patient’s pulse, particularly in adults, where it can be palpated at the antecubital fossa, the bend of the elbow on the inner arm. For infants, the pulse is found higher up the arm, near the middle of the upper arm, between the biceps and triceps muscles. Applying gentle pressure with the index and middle fingers can detect the rhythmic pulsation of the artery.
Measuring blood pressure is another primary use of the brachial artery. A blood pressure cuff is placed around the upper arm, with the cuff’s marker aligned directly over the brachial artery. The cuff is inflated to temporarily stop blood flow. As it slowly deflates, healthcare providers listen for Korotkoff sounds with a stethoscope placed over the artery. The first sound indicates systolic pressure, and the point where the sounds disappear marks diastolic pressure. This method provides a reliable assessment of systemic blood pressure due to the artery’s accessible location at the elbow and consistent blood flow.
The brachial artery is also used for more invasive procedures, such as arterial line insertion. This involves placing a thin catheter into the artery for continuous, precise blood pressure monitoring, especially in critically ill patients. While the radial and femoral arteries are preferred for arterial lines due to lower complication risks, the brachial artery may be chosen as an alternative when other sites are unavailable or for certain complex interventional procedures that require larger access. Ultrasound guidance is often employed during brachial artery cannulation to reduce the risk of complications, such as nerve injury or hematoma formation, given its proximity to the median nerve.
Common Issues and Injuries
The brachial artery, despite its protected location, can be affected by various issues and injuries. Direct trauma, such as fractures of the humerus or deep lacerations, is a frequent cause of damage to the artery. Such injuries can lead to significant bleeding or disruption of blood flow to the limb.
Arterial occlusion, or blockage, is another concern. This can occur due to a blood clot (embolism or thrombosis) forming within the artery or traveling from elsewhere in the body, often from the heart or aorta. Symptoms of an occlusion can include severe pain, numbness, coldness, and a diminished or absent pulse in the hand or fingers, potentially leading to limb ischemia if not addressed quickly.
Less common issues include brachial artery aneurysm, which is an abnormal bulging or weakening in the artery wall, often resulting from trauma but also linked to atherosclerosis, infection, or genetic conditions. These aneurysms may present as a pulsating mass and can lead to complications such as thrombosis or nerve compression. Brachial artery entrapment syndrome is a rare condition where the artery is compressed by surrounding muscles or anatomical abnormalities, leading to reduced blood flow and symptoms like arm pain, weakness, and coldness. Any suspected brachial artery issue requires medical attention to prevent long-term damage and ensure adequate blood supply to the limb.