Anatomy
Summary
The aorta--the grand highway of arterial circulation--starts its journey as the aortic root, acending into the ascending aorta and branching into the aortic arch, eventually flowing downward into the descending aorta. The major branches off the aorta include the coronary arteries that nourish the heart, the brachiocephalic artery, which further divides into the right common carotid and right subclavian arteries. On the left side, the aortic arch gives rise to the left common carotid and left subclavian arteries. The arch is also equipped with baroreceptors and chemoreceptors, which send sensory information via the vagus nerve (CN X) to regulate blood pressure and composition.
Coarctation of the aorta occurs at the aortic isthmus, a narrowed segment often present from birth. The ligamentum arteriosum connects the aortic isthmus to the pulmonary trunk and is a hotspot for traumatic rupture. In subclavian steal syndrome, blood flow reverses in the vertebral artery due to stenosis in the more proximal subclavian artery. The descending aorta serves the thoracic organs with its arterial branches, includin the lungs, esophagus, pericardium, diaphragm, intercostal spaces, and spinal cord. Notably, the descending aorta is situated posterior to the esophagus, providing a route for transesophageal echocardiography (TEE). Aortic dissection creates a false lumen within the aortic wall, categorized as either Stanford type A involving the ascending aorta or Stanford type B involving the descending aorta or more distally.
Lesson Outline
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FAQs
The thoracic aorta is a part of the aorta that is located in the thorax - the part of the body between the neck and the diaphragm. It is the largest artery in the body and its primary function is to carry oxygenated blood from the heart to the rest of the body. It starts from the aortic root and includes the ascending aorta, the aortic arch, and the descending thoracic aorta.
The coronary arteries originate at the aortic root, which is the beginning of the ascending aorta. These arteries supply oxygen-rich blood to the heart muscle itself. There are typically two main coronary arteries, the right coronary artery and the left coronary artery, each supplying different parts of the heart muscle.
The aortic arch has three major branches: the brachiocephalic artery, which splits further into the right common carotid artery and right subclavian artery, the second branch is the left common carotid artery, and the third is the left subclavian artery. These arteries supply oxygenated blood to the head, neck, and upper limbs.
Subclavian steal syndrome is a condition characterized by the flow of blood being reversed in the vertebral artery or the internal thoracic artery due to stenosis in the more proximal subclavian artery. This reversed blood flow occurs as the body attempts to supply adequate blood to the arm despite the narrowed artery. This can cause symptoms such as dizziness, blurred vision, weakness or numbness of the arm, and syncope.
Aortic dissection is a serious condition characterized by a tear in the wall of the aorta. Blood can flow between the layers of the wall of the aorta, causing them to dissect or separate. Stanford type A thoracic aortic dissections involve any part of the ascending aorta, while Stanford type B thoracic aortic dissections occur only in the descending aorta or more distally.
