MSA Anatomy of the Thorax and Human Heart PDF

Anatomy of the Thorax Dr. Gamal Taha Abdelhady Lecturer of Anatomy & Embryology Anatomy of the Human Heart  Anatomy of the Human Heart ◼ By the end of this session, you should be able to: 1. Identify and...

Anatomy of the Thorax Dr. Gamal Taha Abdelhady Lecturer of Anatomy & Embryology Anatomy of the Human Heart  Anatomy of the Human Heart ◼ By the end of this session, you should be able to: 1. Identify and recognize different parts and features concerning the outer and inner surfaces of the heart and its chambers.  Exterior of the Heart A hollow conical fibromuscular organ lies within the pericardium in the middle mediastinum between the lungs and pleurae. Position: It is placed obliquely behind the body of the sternum and adjoining costal cartilages and ribs. Its long axis is directed downwards, forwards & to the left. It rests on the diaphragm, 1/3 of it lies to the right & 2/3 to the left of the median plane. Exterior of the Heart  Heart Relations Organs Associated With The Heart: Inferiorly: central tendon of the diaphragm Superiorly: the great blood vessels; aorta, superior vena cava, pulmonary artery and vein. Posteriorly: oesophagus, trachea, descending aorta Laterally: the lungs Anteriorly: the sternum, ribs and intercostal muscle. Exterior of the Heart  Sulci of the Heart The heart chambers are separated by, ◼ Interatrial groove: separates the two atria and is hidden by pulmonary trunk and aorta in front ◼ Interventricular groove: anterior and posterior interventricular sulci can be found running vertically on their respective sides of the heart. They represent the wall separating the ventricles (Septum).  Sulci of the Heart ◼ The coronary sulcus (or atrioventricular groove) ◼ Runs transversely around the heart, it represents the wall separating the atria from the ventricles. The sulcus contains important vasculature, such as the right coronary artery.  Exterior of the Heart ◼ In its typical anatomical orientation, the heart has 2 surfaces, formed by different internal divisions of the heart: ◼ Anterior (or sternocostal) – Is directed forwards and upwards. The right ventricle represents 2/3 of this part while the left ventricle forms the remaining 1/3. ◼ Inferior (or diaphragmatic) – Is directed downwards and slightly backwards. It rests mainly upon the central tendon of the diaphragm. Is formed by the right and left ventricles (mainly the left) separated by the inferior interventricular groove.  Exterior of the Heart Apex: Is directed downwards, forwards and to the left. Is overlapped by the left lung and pleura. Is formed by the left ventricle. Lies in the left 5th intercostal space, approximately 9 cm from the median plane (Midclavicular Plan). Posterior (or base) – Is quadrilateral in shape and is directed backwards and to the right. Is formed mainly by the left atrium, with a lesser contribution by the right atrium..  Exterior of the Heart Right pulmonary surface and border – Right atrium. Left pulmonary surface and border – Left ventricle and part left atrium Both surfaces are related to the corresponding pleura and lung, phrenic nerve. Sterno - Costal Surface Exterior of the Heart (Diaphragmatic Surface)  Exterior of the Heart ◼ Human heart has 4 chambers ◼ 2 Atria ◼ Superior = primary receiving chambers, do not actually pump ◼ Blood flows into atria towards the ventricles ◼ 2 Ventricles ◼ Pump blood ◼ Contraction = blood sent out of heart + circulated ◼ Chambers are separated by septum… ◼ Due to separate chambers, heart functions as double pump  Borders of the Heart Separating the surfaces of the heart are its borders. There are four main borders of the heart: 1. Right border – Right atrium 2. Inferior border – Left ventricle and right ventricle 3. Left border – Left ventricle (and some of the left atrium) 4. Superior border – Right and left atrium and the great vessels  Pericardium ◼ Fibrous Pericardium The Fibrous Pericardium is the most superficial layer of the pericardium. It is made up of dense and loose connective tissue. It adheres to the diaphragm inferiorly, and superiorly it is fused to the roots of the great vessels that leave and enter the heart Protects the heart, anchors it to the surrounding walls, and prevents it from overfilling with blood  Pericardium ◼ Serous Pericardium ◼ The Serous Pericardium, is divided into two layers, the Parietal Pericardium, which is fused to and inseparable from the fibrous pericardium, and the Visceral Pericardium, which is part of the epicardium. ◼ Lubricates the heart to prevent friction during heart activity. Exterior Surface of the Heart  Exterior Surface of the Heart Right Atrium: It lies in front and to the right of the left atrium. It forms the right border of the heart, the upper part of the sternocostal surface, the convex right (pulmonary) surface and the right side of the base.  Exterior Surface of the Heart Right Atrium cont.: Anteriorly, its upper part is prolonged to the left to form the right auricle which overlaps the right side of the ascending aorta.  Exterior Surface of the Heart The Right Ventricle The right ventricle shares in the formation of: 1. The right 2/3 of the ventricular part of the sternocostal surface. 2. A small part of the diaphragmatic surface. 3. Most of the inferior border of the heart.  Exterior Surface of the Heart ◼ The Right Ventricle Cont.: ◼ The right ventricle communicates with the right atrium through the atrioventricular (tricuspid) orifice and with the pulmonary trunk through the pulmonary orifice. ◼ As the cavity approaches the pulmonary orifice it becomes funnel shaped, and is referred to as the infundibulum.  Exterior Surface of the Heart ◼ Left Atrium ◼ The left atrium is situated behind the right atrium and forms most of the superior border and base of the heart. ◼ The left atrium consists of a main cavity and a left auricle that overlaps the root of pulmonary trunk.  Exterior Surface of the Heart ◼ Left Ventricle: It is cone-shaped being longer and narrower than the right ventricle with its long axis descending forward and to the left. The left ventricle forms: 1. The apex of the heart 2. The smaller part of sternocostal surface 3. Nearly all its left (pulmonary) surface and border 4. Most of the diaphragmatic surface.  Surface Anatomy of the Heart ◼ From the 3rd costal cartilage on the right side of the sternum and the 2nd intercostal space on the left side of the sternum ◼ The right margin of the heart extends from the right 3rd costal cartilage to near the right 6th costal cartilage.  Surface Anatomy of the Heart ◼ The left margin of the heart descends laterally from the 2nd intercostal space to the apex located near the midclavicular line in the 5th intercostal space. ◼ The lower margin of the heart extends from the sternal end of the right 6th costal cartilage to the apex in the 5th intercostal space near the midclavicular line (or 9cm from the midline). Break Anatomy of the Thorax Dr. Gamal Taha Abdelhady Lecturer of Anatomy & Embryology Arterial System  Arterial System ◼ By the end of this session, you should be able to: 1. Define arteries and understand the general principles of arterial system. 2. List major arteries and their branches in the body.  Blood Vessels ◼ Arteries: are vessels that carry blood away from the heart, thick walled and muscular containing no valves. ◼ Veins: are vessels that carry blood to the heart, thin walled and relatively wide having valves.  The Aorta The largest artery in the body Arises from left ventricle carrying oxygenated blood to be distributed to all systems of body. It is divided into 4 parts: 1- Ascending aorta 2- Aortic arch 3- Descending aorta (Thoracic and Abdominal aorta) Ascending Aorta  Ascending Aorta Ascending aorta originates from the upper end of the left ventricle (i.e., aortic vestibule) It’s about 5 cm long and its diameter is about 3 cm. It’s completely enclosed in the pericardium. It begins behind the left half of the sternum in the level of the lower border of left 3rd costal cartilage, runs upwards, slightly forwards and to the right to continue as the arch of aorta at the level of sternal angle. Right coronary artery Left coronary artery Arch of the Aorta  Arch of the Aorta Begins behind sternal angle as a continuation of ascending aorta. Runs upward, backward, and to the left, ending on the left side at vertebral level T4/5. Becomes continuous with the descending thoracic aorta (the level of the sternal angle). From before backwards the arch gives origin to three branches: 1- The brachiocephalic trunk 2- Left common carotid artery 3- Left subclavian artery Right Common carotid artery Right Subclavian artery  Radiological Appearances ◼ In an anteroposterior radiographs, the terminal part of the arch is easily seen as a shadow cast, which is called 'aortic knuckle'.  Brachiocephalic Trunk Is the largest branch of arch of aorta, begins behind the center of manubrium sterni, in front of the trachea. It runs upwards, backwards, and to the right to reach the right side of trachea. Divides behind the right sternoclavicular joint into: 1- Right common carotid artery 2- Right subclavian artery  Left Common Carotid & Subclavian Arteries Left Common Carotid is the 2nd artery to appear from the arch, in front of the trachea. It runs upwards, backwards, and to the left to reach the left side of neck. Lt. Subclavian artery is the 3rd to come off the arch, It runs to the left, to reach the left upper limb.  Descending Thoracic Aorta  Descending Aorta The third part of the aorta is called the descending aorta. It is divided into two parts: 1. The portion of the artery above the diaphragm is known as the thoracic aorta. 2. The portion of the artery Below the diaphragm, the aorta becomes the abdominal aorta.  Descending Thoracic Aorta It is the continuation of arch of aorta, begins at the level of lower border of the body of the 4th thoracic vertebra (opposite sternal angle). It descends through the thorax, to enters aortic opening (aortic hiatus) of diaphragm opposite T12 vertebra and becomes continuous with abdominal aorta.  Branches of Descending Thoracic Aorta 1. Bronchial arteries: Vary in number and origin. 2. Esophageal arteries: Four or five in number, supply esophagus. 3. Mediastinal arteries: Supply various tissues within mediastinum. 4. Pericardial arteries: Supply pericardium.  Branches of Descending Thoracic Aorta 5. Posterior intercostal arteries: They are nine pair, given off to the lower nine intercostal spaces on each side. 6. Subcostal arteries: These are given off on each side and run along lower border of the twelfth ribs to enter the abdominal wall. 7. Superior phrenic arteries: Distributed into the posterior part of superior surface of diaphragm.  Descending Abdominal Aorta  Descending Abdominal Aorta The abdominal aorta begins at the aortic hiatus of the diaphragm, at the level of T12. It descends through the abdomen, anterior to the vertebral bodies, and ends at the level of vertebra L4, slightly to the left of midline. The terminal branches of the abdominal aorta are the two common iliac arteries. The abdominal aorta has anterior, lateral, and posterior branches as it passes through the abdominal cavity.  Anterior Branches of Abdominal Aorta The three anterior branches supply the gastrointestinal viscera. 1- The celiac trunk 2- The superior mesenteric 3- Inferior mesenteric The primitive gut tube can be divided into foregut, midgut, and hindgut regions. The boundaries of these regions are directly related to the areas of distribution of these three anterior branches of the abdominal aorta.  Anterior Branches of Abdominal Aorta The celiac trunk supplies the foregut (mainly Liver and Spleen) The superior mesenteric supplies the midgut (Mainly the small intestine) The Inferior mesenteric supplies the hindgut (Mainly the large intestine) ◼ For further inquiries PLZ feel free to contact at any time through email [email protected]