DR. HAYTHEM ALI ALSAYIGH Assistant prof. BOARD CLINICAL SURGICAL ANATOMY F.I.M.B.S.-MB.CH,B COLLEGE OF MEDICINE –UNIVERSITY OF BABYLON G. Cardiac veins and coronary sinus ()

1. Coronary sinus : Is the largest vein draining the heart and lies in the coronary sulcus , which separates the atria from the ventricles.  Opens into the right atrium between the opening of the IVC and the AV opening. Has a one-cusp valve at the right margin of its aperture.  Receives the great, middle, and small cardiac veins; the oblique vein of the left atrium; and the posterior vein of the left ventricle.

G. Cardiac veins and coronary sinus ()  2. Great cardiac vein :  Begins at the apex of the heart and ascends along with the IV branch of the left coronary artery. Turns to the left to lie in the coronary sulcus and continues as the coronary sinus.  3. Middle cardiac vein:  Begins at the apex of the heart and ascends in the posterior IV groove , accompanying the posterior IV branch of the right coronary artery. Drains into the right end of the coronary sinus. G. Cardiac veins and coronary sinus ()  4. Small cardiac vein :  Runs along the right margin of the heart in company with the marginal artery and then posteriorly in the coronary sulcus to end in the right end of the coronary sinus.  5. Oblique vein of the left atrium :  Descends to empty into the coronary sinus, near its left end.  6. Anterior cardiac vein:  Drains the anterior right ventricle, crosses the coronary groove, and ends directly in the right atrium.  7. Smallest cardiac veins (venae cordis minimae)  Begin in the wall of the heart and empty directly into its chambers. H. Lymphatic vessels of the heart

 Receive lymph from the myocardium and epicardium. Follow the right coronary artery to empty into the anterior mediastinal nodes and follow the left coronary artery to empty into a tracheobronchial node. I. Cardiac plexus

 Receives the superior, middle, and inferior cervical and thoracic cardiac nerves from the sympathetic trunks and vagus nerves. Is divisible into the superficial cardiac plexus , which lies beneath the arch of the aorta in front of the pulmonary artery, and the deep cardiac plexus , which lies posterior to the arch of the aorta in front of the bifurcation of the trachea.  Richly innervates the conducting system of the heart: the right sympathetic and parasympathetic branches terminate chiefly in the region of the SA node , and the left branches end chiefly in the region of the AV node.  The cardiac muscle fibers are devoid of motor endings and are activated by the conducting system. Supplies the heart with sympathetic fibers , which increase the heart rate and the force of the heartbeat and cause dilation of the coronary arteries ,  and parasympathetic fibers , which decrease the heart rate and constrict the coronary arteries. III. Great Vessels

A. Ascending aorta  Takes its origin from the left ventricle within the pericardial sac and ascends behind the sternum to end at the level of the sternal angle. Lies in the middle mediastinum , has three aortic sinuses located immediately above the cusps of the aortic valve, and gives off the right and left coronary artery. B. Arch of the aorta  Is found within the superior mediastinum , begins as a continuation of the ascending aorta, and arches over the right pulmonary artery and the left main bronchus. Forms a prominence that is visible on the radiograph as the aortic knob.  Gives rise to the brachiocephalic, left common carotid, and left subclavian arteries. I. Cardiac plexus  C. Superior vena cava  Is formed by the union of the right and left brachiocephalic veins and returns blood from all structures superior to the diaphragm, except the lungs and heart.  Descends on the right side of the ascending aorta, receives the azygos vein , and enters the right atrium. Its upper half is in the superior mediastinum , and its lower half is in the middle mediastinum.  D. Pulmonary trunk ()  Arises from the conus arteriosus of the right ventricle, passes obliquely upward and backward across the origin and on the left side of the ascending aorta within the fibrous pericardium, and bifurcates into the right and left pulmonary arteries in the concavity of the aortic arch. Structures in the Posterior Mediastinum  I. Esophagus  Is a muscular tube (about 10 inches long) that is continuous with the pharynx in the neck and enters the thorax behind the trachea. Has three constrictions:  one at the level of the sixth cervical vertebra, where it begins;  one at the crossing of the left main stem bronchus; and  one at the tenth thoracic vertebra, where it pierces the diaphragm. The left atrium also presses against the anterior surface of the esophagus.  Has a physiologic sphincter, which is the circular layer of smooth muscle at the gastroesophageal junction. By clinicians, this is called the inferior esophageal sphincter.

 Receives blood from three branches of the aorta (the inferior thyroid, bronchial , and esophageal arteries) and from the left gastric and inferior phrenic arteries. II. Blood Vessels and Lymphatic Vessels  A. Thoracic aorta Begins at the level of the fourth thoracic vertebra.  Descends on the left side of the vertebral column and then approaches the median plane to end in front of the vertebral column by passing through the aortic hiatus of the diaphragm.  Gives rise to nine pairs of posterior intercostal arteries and one pair of subcostal arteries.  The first two intercostal arteries arise from the highest intercostal arteries of the costocervical trunk.  The posterior intercostal artery gives rise to a collateral branch, which runs along the upper border of the rib below the space.  Also gives rise to pericardial, bronchial (one right and two left), esophageal, mediastinal, and superior phrenic branches. II. Blood Vessels and Lymphatic Vessels  B. Azygos venous system  1. Azygos (unpaired) vein  Is formed by the union of the right ascending lumbar and right subcostal veins. Its lower end is connected to the IVC. Enters the thorax through the aortic opening of the diaphragm.  Receives the right intercostal veins, the right superior intercostal vein , and the hemiazygos and accessory hemiazygos veins.  Arches over the root of the right lung and empties into the SVC , of which it is the first tributary.

 2. Hemiazygos vein  Is formed by the union of the left subcostal and ascending lumbar veins. Its lower end is connected to the left renal vein. Ascends on the left side of the vertebral bodies behind the thoracic aorta, receiving the ninth, tenth, and eleventh posterior intercostal veins  3. Accessory hemiazygos vein  Begins at the fourth or fifth intercostal space; descends, receiving the fourth or fifth to eighth intercostal veins; turns to the right; passes behind the aorta; and terminates in the azygos vein.  4. Superior intercostal vein  Is formed by a union of the second, third, and fourth posterior intercostal veins and drains into the azygos vein on the right and the brachiocephalic vein on the left.  5. Posterior intercostal veins  The first intercostal vein on each side drains into the corresponding brachiocephalic vein. The second, third, and often the fourth intercostal veins join to form the superior intercostal vein .  The rest of the veins drain into the azygos vein on the right and into the hemiazygos or accessory hemiazygos veins on the left. C. Lymphatics 1. Thoracic duct  Begins in the abdomen at the cisterna chyli , which is the dilated junction of the intestinal, lumbar, and descending intercostal trunks.  Is usually beaded because of its numerous valves and may often be double or even triple. Drains the lower limbs, pelvis, abdomen, left thorax, left upper limb, and left side of the head and neck.  Passes through the aortic opening of the diaphragm and ascends through the posterior mediastinum between the aorta and the azygos vein.  Arches laterally over the apex of the left pleura and between the left carotid sheath in front and the vertebral artery behind, runs behind the left internal jugular vein, and then usually empties into the junction of the left internal jugular and subclavian veins.  2. Right lymphatic duct  Drains the right sides of the thorax, upper limb, head, and neck. Empties into the junction of the right internal jugular and subclavian veins.