Arteries form a network of muscular tubes responsible for carrying oxygenated blood away from the heart to every tissue and cell in the body. This systemic circulation ensures a continuous supply of oxygen and nutrients needed for cellular function. The thick, elastic walls of these vessels allow them to withstand the high pressure created by the heart’s pumping action. Excluding the pulmonary artery, which transports deoxygenated blood to the lungs, the major arteries are organized into a hierarchical system originating from one central vessel that distributes resources across the human body.
The Aorta: Central Pathway of Circulation
The largest artery in the body is the Aorta, which serves as the main trunk line for the entire systemic arterial system. It begins directly at the heart’s left ventricle, the chamber responsible for pumping blood to the rest of the body. The Aorta immediately arches and descends, creating a continuous pathway that runs down through the torso.
This vessel is structurally divided into three primary segments. The ascending aorta gives rise to the two coronary arteries that supply the heart muscle. The aortic arch curves over the heart and gives rise to the major arteries supplying the upper body. The final and longest segment is the descending aorta, which travels through the chest (thoracic aorta) and abdomen (abdominal aorta), giving off branches to the head, arms, and internal organs.
Arteries Supplying the Head, Neck, and Arms
The upper body receives its primary arterial supply from three major vessels that branch off the aortic arch: the brachiocephalic trunk (on the right), the left common carotid artery, and the left subclavian artery. The common carotid arteries, one on each side, ascend into the neck before dividing into two branches.
The internal carotid arteries supply the brain, while the external carotid arteries supply the face, scalp, neck, and tongue. The subclavian arteries, located beneath the collarbones, supply the arms and also contribute blood to the brain through the vertebral arteries.
As the subclavian artery passes the outer edge of the first rib, its name changes to the axillary artery, supplying the shoulder and armpit region. This vessel then continues down the arm, becoming the brachial artery, the primary source of blood flow for the entire arm. The brachial artery runs along the inner side of the upper arm. Near the elbow, the brachial artery splits into the radial and ulnar arteries, which run through the forearm and supply the hands and fingers.
Arteries Supplying the Abdomen and Vital Organs
The abdominal portion of the descending aorta provides blood to the body’s internal organs through several major branches. The most superior is the celiac trunk, a short, unpaired artery that quickly divides into three main branches: the left gastric artery (supplying the stomach), the splenic artery (supplying the spleen and part of the pancreas), and the common hepatic artery (supplying the liver and gallbladder).
Just below the celiac trunk, the abdominal aorta gives rise to the superior mesenteric artery, which is responsible for supplying the mid-region of the gastrointestinal tract. This includes the small intestine and the first two-thirds of the large intestine. The paired renal arteries branch directly off the abdominal aorta to supply the kidneys with the large volume of blood needed for filtration.
Further down the abdominal aorta is the inferior mesenteric artery, which supplies the remaining sections of the large intestine, including the descending colon, sigmoid colon, and rectum. The coronary arteries, branching from the ascending aorta, deliver oxygen directly to the heart muscle. Without this dedicated supply, the heart cannot sustain the continuous contractions necessary to pump blood to the rest of the body.
Arteries Supplying the Lower Extremities
The main trunk of the Aorta concludes in the lower abdomen by splitting into the two common iliac arteries. These vessels travel downward into the pelvis before dividing into two major branches. The internal iliac arteries supply the organs and musculature within the pelvis, such as the bladder and reproductive organs.
The external iliac arteries are the direct source of blood for the lower limbs. As the external iliac artery passes beneath the inguinal ligament, it is renamed the femoral artery, the largest artery in the thigh. This vessel supplies the musculature in the leg and gives off the deep profunda femoris artery. The femoral artery continues its course until it becomes the popliteal artery behind the knee. The popliteal artery then divides into the anterior and posterior tibial arteries, which supply the lower leg and feet.