right 1st costal cartilage 2. SVC a. enters the RA in the middle mediastinum b. returns venous blood from everything superior to the diaphragm except lungs and heart 3. Arch of the aorta—arches posterosuperior and to the left, anterior to the trachea, then passes inferiorly adjacent to vertebral column. It gives off 3 branches: the brachiocephalic trunk , left common carotid artery and left subclavian artery . 4. Pulmonary Trunk—branches into right and left pulmonary arteries C. Nerves 1. Vagus nerve (CN X) a. right vagus—passes anterior to the subclavian artery, breaks up into the pulmonary plexus posterior to the root of right lung, reforms, then breaks up into the esophageal plexus, and gives branches to the heart and lungs. b. left vagus—passes to the left of arch of the aorta, passes posterior to the root of the left lung, and gives branches to the lungs, esophagus, and heart. c. recurrent laryngeal nerves i. right—hooks under the right subclavian artery to ascend into the neck ii. left—hooks under the ligamentum arteriosum and aortic arch to ascend into the neck between the trachea and esophagus 2. Phrenic nerve a. sole motor supply to diaphragm; sensory to pericardium and diaphragm b. passes anterior to the root of the lung, along the pericardium to enter the diaphragm D. Trachea 1. Fibrocartilaginous tube anterior to the esophagus.
CHA 101 Spring 2020 Page 93 2. Ends by dividing into the main (primary) bronchi at the level of the sternal angle; the dividing point is called the carina. E. Esophagus 1. Fibromuscular tube connecting the pharynx to the stomach. 2. Between the trachea and vertebral column. IV. POSTERIOR MEDIASTINUM A. Thoracic (descending) Aorta 1. Descends along the left side of the vertebral column. 2. Penetrates the diaphragm at T12 (aortic hiatus) along with the thoracic duct and the azygos vein. B. Thoracic Duct 1. Passes upward from the abdomen through the aortic hiatus of the diaphragm, ascends through the posterior mediastinum between the aorta and the azygos vein, then crosses posterior to the esophagus to empty into the junction of the left internal jugular and subclavian veins. 2. Receives all lymph from the left side of the head, neck and thorax, the left upper limb, and the entire body below the diaphragm. Transports fat absorbed from the GI tract back to the venous system. C. Azygos Vein 1. Interconnects the SVC and IVC. 2. Drains the posterior thoracic and abdominal wall. 3. Ascends in posterior mediastinum to the right of the vertebral column, then arches over the root of the right lung to join the SVC. 4. Receives the hemiazygos vein, which ascends on the left side of the vertebral column, and the intercostal veins. D. Esophagus 1. Descends posterior to the left atrium, then through the esophageal hiatus of the diaphragm.
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- Spring '08
- spinal nerves, Brachial plexus