24.22:
The Aorta
The aorta is the largest artery in the human body, with a lumen diameter of about 2.5 cm and a wall thickness of about 2 mm.
It originates from the left ventricle and has an aortic valve to prevent blood backflow during diastole.
The first division of the aorta is the ascending aorta. It gives rise to the right and left coronary arteries that supply blood to the heart muscles.
The ascending aorta curves to the left side of the body, forming the aortic arch, and starts to descend.
The upper segment of the descending aorta between the T5 and T12 vertebrae is called the thoracic aorta. It supplies blood to the chest, pericardium, lungs, and esophagus.
As the descending aorta enters the abdominal cavity, it is called the abdominal aorta.
At the L4 vertebral level, the abdominal aorta branches into the left and right common iliac arteries that supply blood to the pelvis and lower limbs. Various other branches of the abdominal aorta deliver blood to the abdominal organs.
24.22:
The Aorta
The aorta is the largest artery in the human body. It originates from the left ventricle of the heart and extends down to the abdomen, where it splits into two smaller arteries. Structurally, it can be divided into four main parts: the ascending aorta, the aortic arch, the thoracic aorta, and the abdominal aorta.
The average diameter of the aorta is approximately 2-3 cm, but the size can vary depending on the section of the aorta and the individual's age, sex, and body size. The aorta is located slightly to the left of the midline in the thoracic and abdominal cavities.
As the primary artery stemming from the heart, the aorta is responsible for supplying blood to nearly all body tissues. The base of the aorta houses the aortic semilunar valve, which halts the regurgitation of blood into the left ventricle during heart relaxation periods. The ascending aorta, traveling vertically for roughly 5 cm, ends at the sternal angle. After its upward journey, the aorta curves elegantly to the left, forming what is known as the aortic arch. This arch then proceeds downwards, ending at the intervertebral disc between the fourth and fifth thoracic vertebrae. The descending aorta, closely following the vertebrae bodies, moves through the diaphragm via the aortic hiatus. The aorta above this hiatus is referred to as the thoracic aorta, while below it, it becomes the abdominal aorta. The abdominal aorta concludes its course by splitting into two common iliac arteries at the fourth lumbar vertebra.
The aorta is clinically significant. Conditions such as aortic aneurysms, aortic dissection, and aortic stenosis primarily involve the aorta and can be life-threatening if not treated promptly. Understanding the anatomy of the aorta can aid in the timely diagnosis and treatment of these conditions.