BMS 204 - Thoracic Vessels Overview

Study Notes

Learning Objectives: Students should be able to describe the beginning, course, termination, and important relations and branches of thoracic arteries and veins.

Origin: The pulmonary orifice at the 3rd left sternocostal junction.
Course: Ascends, backs, and to the left, encircling the ascending aorta. Has a triple relationship with the ascending aorta.
Termination: Divides into right and left pulmonary arteries at the level of the sternal angle (between T4 and T5). Bifurcation is below the aortic arch.
Branches: Right and left pulmonary arteries; the right is longer and wider than the left. Running horizontally along the superior border of the atria, above the superior pulmonary veins.

Description: Fibrous band connecting the left pulmonary artery and the aortic arch
Function: Obliterated ductus arteriosus of the fetus; reroutes oxygenated blood to the aorta instead of bypassing the non-functioning lungs.
Relations: Superficial cardiac plexus on the right anterior aspect; left recurrent laryngeal nerve on the left posterior aspect.

Origin: At the aortic orifice (3rd left intercostal space)
Course: Obliquely upwards, forwards, and to the right, ending at the arch of the aorta.
Triple Relation: Has a triple relationship with the pulmonary trunk.
Branches: Right coronary artery (from anterior aortic sinus); Left coronary artery (from left posterior aortic sinus).

Origin: 2nd right sternocostal junction of the ascending aorta.
Course: Initially ascending, backward, and leftward, then descending alongside the trachea.
Termination: T4-T5 disc. Transition into descending aorta
Relations upper (convex) aspect related to origins of 3 large branches; lower (concave) aspect related to pulmonary trunk bifurcation. Also related to the left brachiocephalic vein, the ligamentum arteriosum, and left and right recurrent laryngeal nerves. Also related to the trachea; esophagus; thoracic duct.
Branches: brachiocephalic, left common carotid, and left subclavian arteries.

Origin: Arch of aorta at the level of T4-T5 disc.
Course: Descends, first left of the thoracic vertebrae, then in front of the lower 5 thoracic vertebral bodies (T8-T12).
Termination: At the diaphragm's aortic opening, where it merges into the abdominal aorta.
Branches: Nine pairs of posterior intercostal arteries; one pair of subcostal arteries; left bronchial arteries; four or five esophageal branches; small twigs to pericardium and diaphragm.

Function: Drains the upper limbs, head, and neck; and anterior and upper part of posterior thoracic walls
Location: terminates close to 1st right costal cartilage, merging to form the superior vena cava
Right Brachiocephalic Vein: Descends vertically in the superior mediastinum, extending from the medial end of the right clavicle. Empties into the superior vena cava, near the 1st right costal cartilage
Left Brachiocephalic Vein: Descends obliquely, below the upper 1.5 parts of the manubrium. Empties into the superior vena cava, alongside the 1st rib.
Tributaries: Each has the internal thoracic vein, 1st posterior intercostal vein, and superior intercostal vein. Thoracic duct

Formation: Union of the right and left brachiocephalic veins
Course: Descends vertically to penetrate the pericardium at the 2nd right costal cartilage.
Termination: Opens into the right atrium near the 3rd right sternocostal cartilage, close to the sternum.
Tributaries: Azygos vein.