Arteries carry oxygenated blood away from the heart to every tissue in the body. Determining an exact number of “major arteries” is difficult because the definition of “major” is subjective. Anatomical classification typically focuses on the largest and most functionally significant arteries, which serve as the main trunks distributing blood regionally. This discussion categorizes these significant arteries based on the major regions of the body they supply.
The Aorta The Body’s Main Arterial Trunk
The aorta is the largest artery in the body, measuring approximately one inch in diameter at its origin. It emerges directly from the left ventricle of the heart, acting as the starting point for systemic circulation. The aorta’s size and function make it the most significant blood vessel in the body.
The aorta is structurally divided into four main segments as it traverses the body’s midline. It begins as the ascending aorta, which gives rise to the coronary arteries that supply the heart. The vessel then curves to form the aortic arch, followed by the descending aorta. The descending aorta is split into the thoracic aorta in the chest and the abdominal aorta in the lower trunk. All other major arteries originate as direct or indirect branches from this singular structure.
Major Arteries Supplying the Head Neck and Upper Limbs
The three major vessels branching directly from the aortic arch supply the upper body. These include the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery. The brachiocephalic trunk is the first branch, dividing quickly into the right common carotid and the right subclavian arteries.
The common carotid arteries ascend through the neck before bifurcating, typically at the thyroid cartilage. This division forms the internal carotid artery, the primary supplier of blood to the brain, and the external carotid artery, which supplies the face, neck, and scalp. The subclavian arteries travel beneath the clavicle and are the main supply vessels for the upper limbs.
As the subclavian artery passes beyond the first rib, its name changes to the axillary artery, supplying the shoulder and armpit region. This vessel continues down the arm as the brachial artery. At the elbow, the brachial artery typically divides into the ulnar and radial arteries, which run through the forearm and wrist.
Major Arteries Supplying the Abdomen and Visceral Organs
The abdominal aorta continues the main arterial pathway down the trunk, giving off branches to the visceral organs. Unpaired arteries supply the gastrointestinal tract, while paired branches supply structures like the kidneys. The celiac trunk is a short, unpaired vessel that branches off the abdominal aorta just below the diaphragm.
The celiac trunk immediately divides into three major vessels: the common hepatic artery, the splenic artery, and the left gastric artery. These vessels collectively supply the liver, stomach, spleen, pancreas, and the upper small intestine. The superior mesenteric artery (SMA) arises just below the celiac trunk and supplies the midgut, including the entire small intestine and the first two-thirds of the large intestine.
The paired renal arteries branch laterally from the aorta to supply the kidneys. Further down, the inferior mesenteric artery (IMA) branches off to supply the hindgut. This includes the final third of the large intestine and the superior rectum.
Major Arteries Supplying the Lower Limbs
The abdominal aorta concludes its path by splitting into the common iliac arteries. Each common iliac artery then divides into the internal and external iliac arteries near the pelvis. The internal iliac artery primarily supplies the organs and muscles within the pelvic cavity.
The external iliac artery passes beneath the inguinal ligament, where its name changes to the femoral artery. The femoral artery is the largest artery in the leg and is the main supply vessel for the entire lower limb. As it descends through the thigh, it gives off the deep femoral artery, which supplies the large muscles of the thigh.
The femoral artery continues down the posterior aspect of the knee, where it is known as the popliteal artery. Below the knee, the popliteal artery divides into the anterior and posterior tibial arteries. These vessels continue down the leg to supply the lower leg and foot, with the anterior tibial artery becoming the dorsalis pedis artery on the top of the foot.