Heart and great vessels Flashcards
Heart: demonstrate the surface markings of the heart and great vessels, the position and site of auscultation of the heart valves, and explain their clinical relevance; identify the major anatomical features of each chamber of the heart and explain their functional significance; describe the structure and position of heart valves and explain their function; describe the anatomical course of the spread of electrical excitation through the chambers of the heart, recall the position of palpation of
What are the great veins?
Superior vena cava. Inferior vena cava.
What is a tributary? Versus a branch?
A tributary is a vessel of a vein flowing INTO a larger one. Branches describe arteries usually – i.e. vessels that supply tissues/organs.
What is the anatomy of the superior vena cava in the mediastinum – tributaries and positions?
SVC: enters right atrium from above. To the right of the aorta. Formed from asymmetric union of the right and left brachiocephalic (broken down = ‘arm’ then ‘head’) veins. Each brachiocephalic vein forms from an internal jugular vein and a subclavian vein. The internal jugular veins come from the head, and the subclavian veins come from the upper limbs. Left brachiocephalic vein crosses the POSTERIOR region of the manubrium to join the SVC.
What is the position of the inferior vena cava in the mediastinum?
IVC: enters right atrium from below through the CENTRAL TENDON of the diaphragm at T8.
What are the azygos veins?
Azygos means asymmetric. Drain the posterior wall of the thorax and abdomen. ARCHES OVER RIGHT LUNG ROOT TO DRAIN INTO THE SVC. Has many branches (posterior intercostal veins) at the posterior of the chest next to vertebrae. These branches are asymmetric, with most on right side of the body. The only branches on the left side are accessory hemiazygos vein and hemiazygos vein – they cross the thoracic vertebral bodies to join the azygos vein on the right. Emerge through the diaphragm at T10. The arrangement of this venous system is VARIABLE.
What are the relations of the azygos vein to the great vessels in the superior mediastinum?
Azygos is very posterior. Bends anteriorly, above the right pulmonary vein into the SVC – enters posteriorly where the S is, in the third picture.
What are the branches of the ascending aorta and aortic arch?
Ascending aorta: right and left coronary arteries (end arteries supplying heart muscle). The ascending aorta supplies the coronary arteries because ascending aorta contains most oxygenated blood. Aortic arch: brachiocephalic trunk – divides into right common carotid and right subclavian arteries. Left common carotid artery. Left subclavian artery. There’s no left brachiocephalic trunk, hence – the right brachiocephalic trunk is not assigned with ‘right’, and just called brachiocephalic trunk. Carotid – goes to the head. Subclavian – goes to the upper limbs. NOTE that the brachiocephalic trunk lie behind the sternum and lies in the MIDLINE.
What is the relationship of the aorta to the rest of the thorax?
Ascending aorta emerges from the left ventricle on the right side of the heart. It rises anterior to trachea (trachea lies anterior to oesophagus), and arches over the left main bronchus at the lung root at T4. Trachea therefore is posterior to, and between the brachiocephalic and left common carotid arteries. Descending aorta is posterior the oesophagus. Th arch goes over the right pulmonary artery also.
How do the common carotids branch?
Divide into the external and internal carotids high in the neck. These are the main arteries of the head and neck – with the vertebral arteries from the subclavian arteries).
What is the anatomy of the pulmonary trunk?
Outflow from right ventricle. Lies left of the ascending aorta and bifurcates posteriorly to the left and right pulmonary arteries (bifurcates anterior to the descending aorta, and inferior to the aortic arch.
What ligamentous structure is associated with the pulmonary trunk and aortic arch?
LIGAMENTUM ARTERIOSUM connects pulmonary trunk to the aortic arch and is remnant of the ductus arteriosus – bypasses lungs in foetal life.
What is the pericardium?
A fibroserous sac surrounding the heart and its great vessels – leading up to and terminating at the exit of the aorta. The fibrous layer is attached to and blends in with the walls of the great vessels.
What are the layers of the pericardium?
Two layers. Fibrous pericardium outside. Serous pericardium inside – has a parietal (lines fibrous) layer, and visceral (adheres to the heart) layer.
What are the two main pericardial sinuses?
Transverse pericardial sinus – Separates the arteries and the veins. Oblique pericardial sinus – Where the serous pericardium visceral layer is reflecting back on itself to become the parietal layer. This reflection occurs on the pulmonary veins. Can be reached by placing a hand under the apex and moving hand superiorly. Remember, the sinuses are found on the outside of the heart – the pericardium is not found inside the heart.
What is the embryology of the pericardial sinuses?
Heart begins as a tube. The venous end turns upwards during development (hence why most of the vessels in the heart emerge from the top, and the bottom of the heart is just attached to the diaphragm). When these primordial venous and arterial ends are brought together, the transverse pericardial sinus is formed – hence why this is the sinus that separates the arteries and veins. Meanwhile, the veins expand and pericardial reflection (visceral -> parietal) is carried out around them to form oblique pericardial sinus.
How is the pericardium supplied with blood?
Internal thoracic, pericardiophrenic, musculophrenic and inferior phrenic arteries. And descending aorta.
How is the pericardium innervated?
Vagus nerve (cranial nerve X).
How does blood travel through the heart – BASICS?
Into right atrium from pulmonary circulation – via pulmonary veins. etc. etc.
What are the anatomical features of the right atrium?
Found almost posteriorly. Valve is the atrioventricular valve – called tricuspid valve. The two entry points for the vena cava are INLETS – and are aligned with each other such that if you dropped something through the superior vena cava, it would go through the atrium and straight into the inferior vena cava. Both have valves. The opening of the coronary sinus is found at the IVC inlet, and returns blood from the coronary arteries – also has a valve. There’s also small opening of the small cardiac veins scattered along the walls of the RA which drain the myocardium directly. There is a small window in the medial wall called the fossa ovalis (remnant of the foramen ovale). Foramen ovale is present in a foetus and permits passage of blood from the left right to left atrium to bypass the pulmonary circulation. This the first opportunity to bypass the lungs – the second opportunity is called the ligamentum arteriosum. Crista terminalis: The line of union between the right atrium and the right atrial appendage (pouch-like extension of the pectinate muscles), present on the interior of the atrium. The crista terminalis is generally a smooth-surfaced, thick portion of heart muscle. The photo shows the muscle wall REFLECTED, so the crista terminalis is the entire length of the structure that looks like the border. Musculi pectinate are parallel ridges in the walls of the atria of the heart which fan from the crista. Right auricle – the space anterior to the crista and is just a space in the right atrium. IN RELATION TO THE PHOTO: limbus is a border.
What are the anatomical features of the left atrium?
Lies to the posterior of the heart, below where the pulmonary trunk bifurcates. There is an atrioventricular valve also – called the mitral valve. Once again, there is the fossa ovalis. Left auricle.
What are the anatomical features of the right ventricle?
Right ventricle receives blood from the right atria. Pumps blood through the semilunar, pulmonary valves to the lungs. Conus arteriosus – the outflow tract of the right ventricle which leads to the pulmonary trunk. Trabeculae carneae (also called papillary muscles) – net-like structure of the muscular wall found in the inflow portion of the RV and are irregular muscular structures – forms RIDGES and BRIDGES. SOME of these are involved in the valve. Anatomy of the tricuspid valve and pulmonary valve in relation to the ventricle are found in next questions. Septomarginal trabecula – specialised trabeculum forms a bridge between the anterior papillary muscle and interventricular septum and carries a portion of the cardiac conduction to the anterior wall of the RV.
What is the structure of the tricuspid valve and mitral valve?
Remember the number and names of the cusps. The cusps of both valves are tethered to the walls of the ventricle by chordae tendineae via projections called papillary muscles (trabeculae careae). Prevents eversion of the AV valve in the atrial direction, so the muscles and chordae tendineae keep the valves closed during ventricular contraction. The papillary muscles in the LV are larger than in the RV valve.
What is the structure of the semilunar valves in the pulmonary trunk and aorta?
Contain three cusps, which are small sinuses – three pockets.
AORTIC VALVE: In the walls of two of the aortic are two holes – called coronary sinuses – not to be confused with the coronary sinus. These are the openings for the left and right coronary arteries. The sinus with the coronary sinuses inside are called the coronary-aortic sinuses. The sinus without a coronary sinus inside is called the non-coronary-aortic sinus.
What is the anatomy of the arterial part of the coronary circulation? Variation?
Left and right coronary arteries emerge from the aorta. Interventricular coronary arteries – between ventricles. Marginal arteries – go across margins. Circumflex – go back on themselves.
Left coronary artery branches off into the circumflex branch and anterior interventricular branch. These each branch off also – see diagram. Right coronary artery branches off into an early atrial branch (which gives off the sino-atrial nodal branch), a right marginal branch, and the posterior interventricular branch. There is variation about where the posterior interventricular branch arises – can arise from the right coronary artery (called right dominant coronary artery), or the circumflex branch of the left coronary artery. Left dominant coronary artery is LESS common. Try and remember all the names in the photo.
What is the anatomy of the venous part of the coronary circulation?
Veins follow the arteries. Drain into the coronary sinus – sit between left atrium and left ventricle.
What is the anatomy of the conduction system of the heart?
Do not need to focus on this heavily – will talk about this in Cardiovascular System.
What are the surface markings of the heart?
Marked by the following: 1. Just lateral to right sternal border at the 3rd CC (not ICS). 2. Just lateral to right sternal border at the 6th CC. 3. At the position of the apex beat, just medial to the mid-clavicular line in the 5th left ICS. 4. Lateral (about 2.5cm) to the left sternal border at the 2nd CC.
What are the surface markings of the aorta?
Arch begins at the level of the right 2nd CC and ends at the level of the left 2nd CC. Top of the arch is midway between the jugular notch and sternal angle.
What are the surface markings of the main branches of the aorta?
BRACHIOCEPHALIC TRUNK: superolaterally from the aortic arch to the right sternoclavicular joint. Divides into the right subclavian and right common carotid behind the sternoclavicular joint. RIGHT SUBCLAVIAN ARTERY: draw a line laterally from the right sternoclavicular joint arching over the first rib. RIGHT COMMON CAROTID ARTERY: ascends into the neck on the right side of the trachea. Subject should turn their head to the left so that the right sternocleidomastoid muscle becomes visible. The RCC lies below this muscle – draw up to the ear lobe. LEFT COMMON CAROTID ARTERY: Slightly POSTERIOR and left from the brachiocephalic. Subject should turn head to the right and draw a line from the aortic arch towards the sternoclavicular joint and up the SCM muscle to the left ear lobe. LEFT SUBCLAVIAN ARTERY: draw line laterally from the left sternoclavicular joint, arching over the left first rib.
How are the great veins surface marked?
RIGHT AND LEFT INTERNAL JUGULAR VEINS: draw lines just lateral to the common carotids to reach the sternoclavicular joints. RIGHT AND LEFT SUBCLAVIAN VEINS: draw lines parallel to the subclavian ARTERIES to meet the internal jugular veins. The subclavian and internal jugular veins unite to form the brachiocephalic veins. RIGHT BRACHIOCEPHALIC: draw a line from the right sternoclavicular joint to the inferior border of the right 1st CC – not palpable. LEFT BRACHIOCEPHALIC: draw a line from the left sternoclavicular joint to the inferior border of the right 1st CC which runs behind the manubrium from left to right. The right and left brachiocephalic veins unite behind the right 1st CC to form the SVC. SUPERIOR VENA CAVA: draw a line from the right 1st CC to the right 3rd CC running behind the right side of manubrium and sternum to join the right atrium.
Where are the heart valves located in relation to the surface anatomy?
All behind the sternum. Pulmonary = 3rd CC; Mitral – 4th CC; Aortic = 3rd ICS; Tricuspid = 4th ICS. Indicated by the black lines and blue circles in the image.
How are each of the valves auscultated?
TRIUSPID: left 5th ICS near the sternum – because this is the direction the blood is pumped from the RA to the RV. MITRAL: lefts 5th ICS at the MCL = apex beat. PULMONARY: left 2nd (or 3rd) ICS near the sternum. AORTIC: right 2nd ICS near the sternum.
