Q: What is the space between the two pleural sacs called? A: The thoracic mediastinum. Q: What two structures of the thorax are not contained in the thoracic mediastinum? A: The lungs and the pleura. Q: What are the attachments of the thoracic mediastinum? A: Inferiorly : superior thoracic aperture to diaphragm Anteriorly : sternum and costal cartilages Posteriorly : bodies of the thoracic vertebrae Q: What surrounds the structures in the mediastinum? A: Loose connective tissue, nerves, blood, lymphatic vessels and fat. Q: What is the purpose in the mediastinum of the looseness of the connective tissue and fat and the elasticity of the lungs and pleura? A: To accomodate movement and changes in volume in the thoracic cavity. Q: What plane divides the mediastinum? A: The manubriosternal plane (passing through the sternal angle and the inferior border of t4 vertebra). Q: What divides the inferior mediastinum, and what are the compartments called? A: The pericardium and anterior, middle and posterior. Q: What structures are contained in the superior mediastinum? A: The thymus anteriorly, the aortic arch, brachiocephalic trunk, left common carotid artery and left subclavian artery in the middle and the oesophagus, trachea and thoracic duct posteriorly. It also contains the vagus nerve, recurrent laryngeal nerves, phrenic nerves and cardiac sympathetic nerves. Q: Which is the smallest division of the mediastinum? A: The anterior mediastinum. Q: Where is the anterior mediastinum located in relation to the pericardium and sternum? A: Anterior to the pericardium, posterior to the sternum. Q: Why is the middle mediastinum the subdivision of highest clinical importance? A: It contains the pericardium, heart and immediately adjacent parts of the great arteries, proximal end of the azygos vein, phrenic nerves, main bronchi and other structures in the root of the lungs. Q: Where is the posterior mediastinum located in relation to the pericardium and vertebral column? A: Posterior to the pericardium, anterior to the inferior 8 thoracic vertebrae. Q: What are the posterior mediastinum's contents? A: The oesophagus, the descending thoracic aorta, trachea, bronchi, thoracic duct, azygos and hemiazygos veins, vagus nerve, splanchnic nerves and lymph nodes. Q: The heart is a double self-adjusting muscular pump, the two parts of which normally work in unison. Which side recieves deoxygenated blood and where does it pump it to? A: The right side, to the lungs. Q: Which side of the heart recieves oxygenated blood and where doe it pump it? A: The left side, to the aorta for systemic distribution. Q: How many chambers does the heart have? A: 4 Q: The wall of each chamber in the heart consists of 3 layers. What are they? A: Endocardium (internal), myocardium (middle), epicardium (external). Q: In which subdivision of the mediastium is the heart contained? A: The middle mediastium. Q: The heart is situated obliquely in the middle mediastium, approximately what proportion of the heart is left of the median plane? A: 2/3 Q: The base of the heart is located posteriorly and formed mainly by what? A: The left atrium. Q: The base of the heart lies opposite which vertebrae in supine and erect position? A: Supine: T5 to T8 Erect : T6 to T9 Q: What approximate shape is the posterior aspect of the heart? A: Quadrilateral. Q: Where in the heart do the ascending aorta and pulmonary trunk emerge and where does the superior vena cava enter? A: The superior part of the posterior aspect of the heart. Q: What seperates the diaphragmatic surface of the heart from its base? A: The coronary groove. Q: What froms the apex of the heart and in which direction does it point? A: The left ventricle and inferolaterally. Q: Where is the apex of the heart located in most adults? A: Posterior to the left 5th intercostal space, 7 to 9 cm from the median plane, and just left of the midclavicular line. Q: What is the 'apex beat' of the heart? A: It is an impulse imparted by the heart; it is its point of maximal pulsation or the lowest, most lateral point at which pulsation can be felt. Q: What are the 3 surfaces of the heart? A: Sternocostal (or anterior), Diaphragmatic (or inferior) and Pulomonary (or left). Q: What is the sternocostal surface of the heart primarily formed by? A: The right ventricle. Q: What is the diaphragmatic surface of the heart formed by? A: Both ventricles, but mainly the left one. Q: What divides the diaphragmatic surface of the heart into right and left and into what proportions does it divide it? A: The posterior interventricular sulcus, right 1/3 and left 2/3. Q: What is the pulmonary surface of the heart mainly formed by? A: The left ventricle. Q: What part of the lung does the pulmonary surface of the heart occupy? A: The cardiac notch of the left lung. Q: What are the 4 borders of the heart? A: Right, left, inferior and superior. Q: Which surface do the borders of the heart border? A: The sternocostal surface. Q: The right border of the heart is almost in line with which 2 structures? A: The superior and inferior vena cavae. Q: What is the right border of the heart formed by? A: The right atrium. Q: What is the inferior border of the heart formed by? A: Mainly by the right ventricle, partially by the left ventricle. Q: What is the left border of the heart formed by? A: Mainly by the left ventricle, only partially by the left auricle. Q: What is the superior border of the heart formed by? A: The right and left auricles and the superior conical portion of the right ventricle - the conus arteriosus Q: Where does the pulmonary trunk arise from? A: The conus arteriosus. Q: Where is the true cardiac apex in relation to the apex beat? A: Inferolateral. Q: What corresponds to a line from the right 3rd costal cartilage's superior border (1.2 cm from the sternal margin) to the 6th costal cartilage's junction with the sternum? A: The right border of the heart. Q: The left border of the heart is marked by a line which runs from the apex beat to what? A: The lower border of the left 2nd costal cartilage 1.2 cm from the sternal margin. Q: Where would be the best place to listen for a murmur associated with the mitral valve? A: At the apex. Q: Where would be the best place to listen for a murmur associated with the tricuspid valve? A: Left sternal edge, 4th intercostal space. Q: Where would be the best place to listen for a murmur associated with the aortic valve? A: 2nd right intercostal space. Q: Where would be the best place to listen for a murmur associated with the pulmonary valve? A: 2nd left intercostal space. Q: In a PA radiograph of the thorax, what would form the right border of the cardiovascular silhouette (superior to inferior)? A: The superior vena cava, the right atrium and the inferior vena cava. Q: In a PA radiograph of the thorax, what would form the left border of the cardiovascular silhouette (superior to inferior)? A: The arch of the aorta, the pulmonary trunk, the left auricle and the left ventricle. Q: Which sulcus separates the atria from the ventricles? A: The coronary sulcus. Q: What two sulci seprate the two ventricles? A: The anterior and posterior interventricular sulci. Q: Where does the right atrium of the heart receive blood from? A: The superior vena cava, the inferior vena cava and the coronary sinus. Q: What is the smooth posterior part of the internal wall of the right atrium called? A: Sinus venarum. Q: What is the rough anterior part of the internal wall of the right atrium called? A: Musculi pectinati. Q: What is the right auricle of the heart? A: A small conical muscular pouch that projects to the left from the right atrium and overlaps the ascending aorta. Q: What structures separate the two distinct parts of the right atrium (internally and externally)? A: Internally: Crista terminalis Externally: Sulcus terminalis Q: What forms the posteromedial wall of the right atrium of the heart? A: The interatrial septum. Q: What is the name of the thumb print sized, large, shallow, translucent, oval depression on the interatrial septum of the heart? A: Fossa ovalis. Q: What is the incomplete margin bordering the fossa ovalis of the heart known as? A: The limbus fossae ovalis. Q: What structure of the heart is located between the right atrioventricular orifice and the orifice of the IVC? A: The opening of the coronary sinus. Q: What is the clinical significance of Atrioseptal Defect (ASD)? A: Before birth there is a communication between the right and left atria but it normally closes before birth. However in 25% of people there remains a small communication through fossa ovalis. A small ASD is usually of no clinical significance, but a large ASD allows recently oxygenated blood in the left atrium to flow back to the right atrium (where there is lower pressure). Consequently the right side of the heart becomes overworked and the RA, SVC and IVC may become dilated. The right cardiac margin enlarges to the right and an elevated jugular pulse may be observed. Q: What two structures does the conus arteriosus (infundibulum or outflow tract) connect? A: The right ventricle and the pulmonary trunk. Q: What part of the inner wall of the right ventricle is smooth? A: The inner wall of the conus arteriosus. Q: What name is given to the irregular muscle bundles and ridges which make most of the inner wall of the right ventricle of the heart rough? A: Trabeculae carneae. Q: Where does the septomarginal trabecula run in the right ventricle? A: From the interventricular septum to the base of the anterior papillary muscle. Q: The interventricular septum carries what in order to ensure rapid depolarisation of the right ventricular muscle? A: Part of the right bundle branch. Q: What structure separates the atrioventricular tract from the outflow orifice? A: The supraventricular crest. Q: Where do the chordae tendineae of the heart attach? A: The apices of the papillary muscles and the free edges and ventricular surfaces of the cusps of the right atrioventricular valve. Q: What purpose do the chordae tendineae of the heart serve? A: They prevent the cusps of the tricuspid valve from being driven into the right atrium when ventricular pressure arises. Q: What are the usual three papillary muscles of the right ventricle? A: Anterior, posterior and septal. Q: Where is the left atrium in relation to the pulmonary trunk? A: Left and anterior. Q: How many pulmonary veins enter the left atrium? A: Four, two on each side. Q: The floor of the fossa ovalis on the right atrial side of the heart corrseponds to what structure in the left atrium? A: The valvule of the foramen ovale on the inter atrial septal wall. Q: What connects the left atrium to the left ventricle? A: The left atrioventricular orifice. Q: How many cusps does the mitral (left atrioventricular) valve have? A: 2 Q: Are there more and larger musculi pectinati in the left or right atrium? A: The right atrium. Q: How many papillary muscles does the left ventricle have and what are they? A: 2, anterior and posterior. Q: The aortic vestibule leads from the left ventricle into what? A: The semilunar aortic valve. Q: What are the cusps of the aortic valve? A: Left, right and posterior. Q: Where do you find the nodules in the aortic valve? A: At the apex of each cusp. Q: What are the two parts of the interventricular septum? A: The muscular, inferior part and the membranous, superior part. Q: The superior membranous part of the interventricular septum lies toward the aortic valve and is partly confluent with which two cusps? A: The right and posterior. Q: How much thicker is the left ventricular wall compared to the right ventricular wall? A: 2-3 times. Q: What are the layers of the cardiac wall? A: Endocardium, myocardium and epicardium. Q: What is the epicardium made up of? A: Subepicardial fat and connective tissue beneath the visceral layer of the serous pericardium. Q: What are the 4 functions of the cardiac fibrous skeleton? A: 1. To ensure electrophysiological discontinuity between the atria and ventricles. 2. To provide mechanical attachment for the atrial and ventricular muscles. 3. To maintain the cardiac position within the pericardium. 4. To provide a stable but deformable base for the valvular fibrous cores. Q: What structure in the heart can be described as 'a complex framework of dense collagen, with membranous, tendinous and fibro-areolar extensions, approximately along the plane of the coronary sinus, and intimately related to the valve orifices of the atrioventricular and semilunar valves'? A: The cardiac fibrous skeleton. Q: Which three vales of the heart are intimately interconnected through their basal collagenous frameworks? A: The aortic and the two atrioventricular. Q: What is the difference between the superficial and deep layers of the atrial fibres? A: The superficial fibres are common to both atria where as the deep are confined to each atrium. Q: The deep layer of ventricular fibres contribute to which muscles? A: The papillary muscles. Q: What arrangement of fibres does the ventricular myocardium have to enable it to reduce in all dimensions simultaneously? A: The fibres are arranged in a series of nested spiral laminae of varying obliquity. Q: What does 'MCL 5LICS' stand for and what does it indicate? A: Mid Clavicular Line 5th Left Inter Costal Space and the normal position of the apex beat.