Arteries are vessels responsible for delivering oxygen-rich blood and nutrients throughout the human body. Understanding the routes of these major arteries, especially those supplying the limbs, provides insight into the body’s design and operation.
Upper Limb Arteries Overview
The arterial supply to the upper limb begins with the subclavian artery. On the right, it branches from the brachiocephalic trunk, while on the left, it arises directly from the aortic arch. Both subclavian arteries travel laterally, passing between the anterior and middle scalene muscles. As the subclavian artery reaches the outer border of the first rib, it transitions and is renamed the axillary artery, entering the axilla.
The axillary artery courses through the axilla, enveloped by a protective sheath and accompanied by nerves of the brachial plexus. This artery is functionally divided into three parts based on its relationship to the pectoralis minor muscle. It supplies blood to the shoulder region, the upper part of the arm, and portions of the chest wall.
The Point of Transition
The axillary artery changes its name to the brachial artery at a specific anatomical boundary. This transition occurs precisely at the lower border of the teres major muscle, a thick, flattened muscle located in the posterior part of the shoulder. This muscular landmark serves as a consistent point for anatomical and clinical reference.
The brachial artery extends down the front of the upper arm, positioned along the humerus bone. It gives off several branches along its course, providing blood to muscles like the biceps brachii, triceps brachii, and coracobrachialis. Near the elbow, in the cubital fossa, the brachial artery typically divides into its two main terminal branches: the radial and ulnar arteries, which supply the forearm and hand.
Clinical Importance
Understanding the transition between the axillary and brachial arteries is important in medical practice. Healthcare professionals use this anatomical knowledge for diagnostic and procedural purposes. For instance, the brachial artery is commonly used to measure blood pressure, with a cuff placed around the upper arm and a stethoscope positioned over the artery at the elbow to detect blood flow sounds.
The pulse of the brachial artery can be felt on the inside of the arm, useful in pediatric assessments. Knowledge of these arteries is also important during surgical procedures involving the upper limb or shoulder, such as bypass grafting or axillary lymph node dissections, to avoid arterial damage. Damage to these vessels, from trauma or aneurysms, can lead to significant blood flow issues, making precise anatomical understanding fundamental for diagnosis and intervention.