Question 51 of 560 What is the anatomical level of the transpyloric plane? T11 T12 L1 L4 T10 Theme from January 2015 Exam Please rate this question: Discuss and give feedback Next question Transpyloric plane Transpyloric plane Level of the body of L1 Pylorus stomach Left kidney hilum (L1- left one!) Right hilum of the kidney (1.5cm lower than the left) Fundus of the gallbladder Neck of pancreas Duodenojejunal flexure Superior mesenteric artery Portal vein Left and right colic flexure Root of the transverse mesocolon 2nd part of the duodenum Upper part of conus medullaris Spleen Question 52 of 560 A 35 year old man falls and sustains a fracture to the medial third of his clavicle. Which vessel is at greatest risk of injury? Subclavian vein Subclavian artery External carotid artery Internal carotid artery Vertebral artery Theme from April 2013 exam Theme from April 2014 exam The subclavian vein lies behind subclavius and the medial part of the clavicle. It rests on the first rib, below and in front of the third part of the subclavian artery, and then on scalenus anterior which separates it from the second part of the artery (posteriorly). Please rate this question: Discuss and give feedback Next question Clavicle The clavicle extends from the sternum to the acromion and helps prevent the shoulder falling forwards and downwards. The inferior surface is irregular and strongly marked by ligaments at each end. Laterally, lies the trapezoid line and this runs anterolaterally. Posteriorly, lies the conoid tubercle. These give attachment to the conoid and trapezoid parts of the coracoclavicular ligament. The medial part of the inferior surface has an irregular surface which marks the surface attachment of the costoclavicular ligament. The intermediate portion is marked by a groove for the subclavius muscle. Medially, the superior part of the bone has a raised surface which gives attachment to the clavicular head of sternocleidomastoid. Sternohyoid gains attachment to the posterior surface. Laterally there is an oval articular facet for the acromion and a disk lies between the clavicle and acromion. The capsule of the joint is attached to the ridge on the margin of the facet. Next question Question 53 of 560 Where are the greatest proportion of musculi pectinati found? Right ventricle Left ventricle Right atrium Pulmonary valve Aortic valve The musculi pectinati are found in the atria, hence the reason that the atrial walls in the right atrium are irregular anteriorly. The musculi pectinati of the atria are internal muscular ridges on the anterolateral surface of the chambers and they are only present in the area derived from the embryological true atrium. Please rate this question: Discuss and give feedback Next question Heart anatomy The walls of each cardiac chamber comprise: Epicardium Myocardium Endocardium Cardiac muscle is attached to the cardiac fibrous skeleton. Relations The heart and roots of the great vessels within the pericardial sac are related anteriorly to the sternum, medial ends of the 3rd to 5th ribs on the left and their associated costal cartilages. The heart and pericardial sac are situated obliquely two thirds to the left and one third to the right of the median plane. The pulmonary valve lies at the level of the left third costal cartilage. The mitral valve lies at the level of the fourth costal cartilage. Coronary sinus This lies in the posterior part of the coronary groove and receives blood from the cardiac veins. The great cardiac vein lies at its left and the middle and small cardiac veins lie on its right. The smallest cardiac vein (anterior cardiac vein) drains into the right atrium directly. Aortic sinus Right coronary artery arises from the right aortic sinus, the left is derived from the left aortic sinus, which lies posteriorly. Right and left ventricles Structure Left Ventricle A-V Valve Mitral (double leaflet) Walls Twice as thick as right Trabeculae carnae Much thicker and more numerous Right coronary artery The RCA supplies: Right atrium Diaphragmatic part of the left ventricle Usually the posterior third of the interventricular septum The sino atrial node (60% cases) The atrio ventricular node (80% cases) Left coronary artery The LCA supplies: Left atrium Most of left ventricle Part of the right ventricle Anterior two thirds of the inter ventricular septum The sino atrial node (remaining 40% cases) Innervation of the heart Autonomic nerve fibres from the superficial and deep cardiac plexus. These lie anterior to the bifurcation of the trachea, posterior to the ascending aorta and superior to the bifurcation of the pulmonary trunk. The parasympathetic supply to the heart is from presynaptic fibres of the vagus nerves. Valves of the heart Mitral valve Aortic valve Pulmonary valve Tricuspid valve 2 cusps 3 cusps 3 cusps 3 cusps First heart sound Second heart Second heart First heart sound sound sound 1 anterior cusp 2 anterior cusps 2 anterior cusps 2 anterior cusps Attached to chordae No chordae No chordae Attached to chordae tendinae tendinae Next question Question 54 of 560 Which of the following structures separates the subclavian artery and vein? Digastric muscle Prevertebral fascia Anterior scalene muscle Middle scalene muscle Omohyoid The anterior scalene muscle is an important anatomical landmark and separates the subclavian vein (anterior) from the subclavian artery (posterior). Please rate this question: Discuss and give feedback Next question Scalene muscles The 3 paired muscles are: Scalenus anterior: Elevate 1st rib and laterally flex the neck to same side Scalenus medius: Same action as scalenus anterior Scalenus posterior: Elevate 2nd rib and tilt neck to opposite side Innervation Spinal nerves C4-6 Origin Transverse processes C2 to C7 Insertion First and second ribs The brachial plexus and subclavian artery pass between the anterior and Important middle scalenes through a space called the scalene hiatus/fissure. relations The subclavian vein and phrenic nerve pass anteriorly to the anterior scalene as it crosses over the first rib. Image sourced from Wikipedia Thoracic outlet syndrome The scalenes are at risk of adhering to the fascia surrounding the brachial plexus or shortening causing compression of the brachial plexus when it passes between the clavicle and 1st rib causing thoracic outlet syndrome. Next question Question 55 of 560 A 33 year old man is stabbed in the right chest and undergoes a thoracotomy. The right lung is mobilised and the pleural reflection at the lung hilum is opened. Which of the structures listed below does not lie within this region? Pulmonary artery Azygos vein Pulmonary vein Bronchus None of the above The pleural reflections encase the hilum of the lung and continue inferiorly as the pulmonary ligament. It encases the pulmonary vessels and bronchus. The azygos vein is not contained within it. Please rate this question: Discuss and give feedback Next question Lung anatomy The right lung is composed of 3 lobes divided by the oblique and transverse fissures. The left lung has two lobes divided by the oblique fissure.The apex of both lungs is approximately 4cm superior to the sterno-costal joint of the first rib. Immediately below this is a sulcus created by the subclavian artery. Peripheral contact points of the lung Base: diaphragm Costal surface: corresponds to the cavity of the chest Mediastinal surface: Contacts the mediastinal pleura. Has the cardiac impression. Above and behind this concavity is a triangular depression named the hilum, where the structures which form the root of the lung enter and leave the viscus. These structures are invested by pleura, which, below the hilum and behind the pericardial impression, forms the pulmonary ligament Right lung Above the hilum is the azygos vein; Superior to this is the groove for the superior vena cava and right innominate vein; behind this, and nearer the apex, is a furrow for the innominate artery. Behind the hilum and the attachment of the pulmonary ligament is a vertical groove for the oesophagus; In front and to the right of the lower part of the oesophageal groove is a deep concavity for the extrapericardiac portion of the inferior vena cava. The root of the right lung lies behind the superior vena cava and the right atrium, and below the azygos vein. The right main bronchus is shorter, wider and more vertical than the left main bronchus and therefore the route taken by most foreign bodies. Image sourced from Wikipedia Left lung Above the hilum is the furrow produced by the aortic arch, and then superiorly the groove accommodating the left subclavian artery; Behind the hilum and pulmonary ligament is a vertical groove produced by the descending aorta, and in front of this, near the base of the lung, is the lower part of the oesophagus. The root of the left lung passes under the aortic arch and in front of the descending aorta. Image sourced from Wikipedia Inferior borders of both lungs 6th rib in mid clavicular line 8th rib in mid axillary line 10th rib posteriorly The pleura runs two ribs lower than the corresponding lung level. Bronchopulmonary segments Segment number Right lung Left lung 1 Apical Apical 2 Posterior Posterior 3 Anterior Anterior 4 Lateral Superior lingular 5 Medial Inferior lingular 6 Superior (apical) Superior (apical) Segment number Right lung Left lung 7 Medial basal Medial basal 8 Anterior basal Anterior basal 9 Lateral basal Lateral basal 10 Posterior basal Posterior basal Next question Question 56 of 560 A 56 year old man requires long term parenteral nutrition and the decision is made to insert a PICC line for long term venous access. This is inserted into the basilic vein at the region of the elbow. As the catheter is advanced, into which venous structure is the tip of the catheter most likely to pass from the basilic vein? Subclavian vein Axillary vein Posterior circumflex humeral vein Cephalic vein Superior vena cava The basilic vein drains into the axillary vein and although PICC lines may end up in a variety of fascinating locations the axillary vein is usually the commonest site following from the basilic.