Anatomy of the thorax


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Anatomy of the thorax

  1. 1. AnatomyThe Chest Wall and Thoracic Apertures1. List the layers of the thoracic wall12. What is supplied by the (i) posterior and (ii) anterior rami?23. Where is the Angle of Louis?34. Why can the first rib not be palpated?45. Name the bones that make up the thoracic cage?56. In what way are the ribs angled to assist forced breathing?67. Which ribs are typical and atypical and why?78. Define the ‘thoracic inlet’ and ‘thoracic outlet’?89. List the structures that pass through the thoracic inlet?910.What are the attachments of the diaphragm?101 Skin, Superficial Fascia, Serratus Anterior (External Intercostal), Internal Intercostal, Innermost Intercostal,Parietal Pleura and Visceral Pleura2 Anterior supply the internal intercostal muscles, sympathetic nerves to skin and blood vessels (via thoracictrunk), and parietal pleura, Posterior supply post vertebral3 Where the 2nd rib attaches to the sternum, at the joint between the manubrium (top of sternum) and bodyof the sternum, known as the sternal angle.4 Because it lies deep to the clavicle5 Sternum (Manubrium, body and Xiphisternum), Ribs 1-7 (attached to sternum via cartilage), 8-10 (attachedto sternum via chondrochondral joints) 11-12 (free floating ribs), Thoracic vertebrae.6 In adults, the ribs are angled so that they can be pulled straight to improve breathing7 Typical ribs are 3-10 because they are attached to cartilage anteriorly, have a tubercle (muscle attachment)and sub costal groove (where intercostal nerve, vein and artery sit). Atypical ribs are the 1st, 2nd (becausethey are flatter than typical ribs), 11th and 12th (because they are not attached anteriorly)8 Thoracic inlet is the bony-cartilaginous ring formed by the circle of the 1st rib and sternum. The thoracicoutlet (inferior to thoracic inlet) is the osseo-cartilaginous hole in the diaphragm through which abdomen-bound structures pass (oesophagus, IVC and aorta)9 Oesophagus, Trachea, Branches of aorta: common carotid artery and subclavian artery, Internal jugularand subclavian vein. (Compressed in thoracic OUTLET syndrome)10 The ribs (including 11th and 12th) all the way round, and the costal cartilage.
  2. 2. 11.Where are the attachments of the scalene andsternocleidomastoid muscles?1112.What and where is the phrenic angle?1213.Which arteries supply the chest wall?1314. Label the posterior thoracic venous drainagenumbered 1-4 on the diagram1415.Which veins drain the chest wall anteriorly?1516.Which areas do the (i) superficial and (ii) deepthoracic lymphatics mostly travel towards?16Anatomy of Breathing1. What is a URTI?172. At which part of the lung are the visceral pleura and parietal pleura continuous?183. Which layer of the pleural membrane is sensitive and which is not?194. What is the function of pleural fluid?205. Which two factors contribute to the elasticity and surface tension of the lungs?2111 Scalene muscles stabilise the neck and are attached to the cervical vertebrae and 2nd rib. Thesternocleidomastoid (all in the name) is attached to the sternum, clavicle and mastoid process of the skull.12 Where the separated from the chest wall by a narrow angle (especially when breathing out). The lungtissue rarely enters this gap even when fully breathing in.13 Branches from thoracic aorta (back) = internal thoracic arteries. Branches derived from subclavian arteries(edge of sternum/front) = anterior intercostal.14 1 = Superior vena cava, 2 = Azygos vein, 3 = Hemiazygos vein (inferior to 4), 4= hemiazygos vein15 Veins allied to the internal thoracic arteries which follow the same route.16 Superficial = axilla (armpit), Deep = thoracic duct17 Upper Respiratory Tract Infection - A viral infection located in the respiratory tract anywhere above thevocal cords.18 Hilum (top) of ling19 Parietal only20 Lubrication during movement of the chest cavity21 Surfactant (produced by type II pneumocytes), and elastic tissue in the lung connective tissue
  3. 3. 6. What causes the pleural cavity to have a negative pressure?227. Why is an upright posture better than a slouched posture for a patient inrespiratory distress?238. Where do the IVC, oesophagus and abdominal aorta pass through the diaphragm?249. Which vertebrae give rise to the phrenic nerves that innervate the diaphragm?2510.List the layers of muscles in the intercostal space, what are their functions?2611.What is flail chest?2712.Define ‘inspiratory muscles’ and ‘expiratory muscles’ and list a few examples ofeach?2813.Which muscles are involved in quiet inspiration?2914.Which muscles are involved in forced inspiration?3015.Which muscles are involved in quiet exhalation?3122 Pressure in pleural cavity is below atmospheric pressure purely because of surface tension created bypleural fluid, think of pulling apart two wet plates23 Gravity assists the diaphragm by causing descent of the heavy abdominal organs, when lying flat the ribcage is in contact with the ground and its movement is impeded.24 oesophagus and aorta pass through the muscular portion (adjacent to the psoas major muscle) at theback, oesophagus through the ʻright crusʼ which acts as a sphincter to prevent stomach being sucked backinto thorax. The IVC passes through the cartilaginous section of the diaphragm in the centre (caval opening).25 C3,4 and 5 keep you alive26 External intercostal muscle (forwards and downwards), internal intercostal muscle, innermost intercostalmuscle. Could include serratus anterior. All capable of raising chest in forced breathing.27 A condition where the chest is damaged in a way that prevents the intercostal muscles from stopping itbellowing out during expiration. The intercostals normally contract during inspiration and expiration tomaintain a consistent shape in the chest wall.28 Inspiratory is anything which elevates the chest and expiratory is anything which depresses the chest.Diaphragm can act as both, pectoralis major (inspiratory), sternocleidomastoid (inspiratory in forcedbreathing), rectus abdominis (expiratory)29 Diaphragm, scalene (stabilises 1st rib), intercostals (to prevent ʻflail chestʼ)30 Scalenes and sternocleidomastoid, pectoralis major and minor, intercostals, quadratus lumboram31 Quiet exhalation can be done passively due to elastic recoil of lungs and gravity, although commonly thediaphragm and intercostals are involve for stabilizing.
  4. 4. 16.Which muscles are involved in forced exhalation?32Respiratory Tract, Lungs and Pleurae1. What type of epithelium is unique to the respiratory tract?332. How do the nasal cavities function as a protective mechanism?343. Which nerve supplies the bronchoconstrictor muscle?354. What is the function of the larynx?365. What is the piriform fossae?376. What are the potential hazards of performing an emergency laryngotomy?387. What are the 3 cartilage structures that make up the larynx?398. Which muscle can modify the diameter of the trachea?409. What is the basic structure of the trachea and early bronchi?4110.At which vertebral level does the trachea bifurcate into two bronchi?4232 Abdominals, intercostals, latissimus dorsi.33 Pseudo stratified columnar ciliated epithelium, specifically the mucocilliary escalator which consists of aʻgelʼ phase which sits on top of the cillia and a ʻsolʼ phase which sits on and around the cilia beneath the gel.34 Openings of the nasal cavities have hairs which trap large airborne particles. Serous glands in nasalcavities secrete antibiotic enzymes. Mucous environment traps bacteria and particles.35 Vagal, because parasympathetic stimulation causes bronchoconstriction. The vagus nerve also respondsto stretch, chemical environment and irritant receptors to initiate the cough reflex. The cough reflex involvedthe medulla.36 Primarily as a sphincter of the airway, its superior margin is bounded by the aryepiglottic muscles whichclose the airway itself.37 It is a channel either side of the laryngeal inlet. The inlet is raised allowing fluids to run into the piriformfossae.38 Risk of causing damage to the lobe extending into the median plane which is present in 1% of people.39 From top to bottom: Thyrohoid membrane, thyoid cartilage, cricothyoid membrane, cricoid cartilage40 C shaped rings of smooth muscle41 Mucocilliary epithelium inside C shaped rings of hyaline cartilage interspersed with smooth (trachielis)muscle42 T4 at expiration (when pushed up)
  5. 5. 11. Why is an inhaled foreign object 80% more likely to enter the right lung?4312.What and where is the carina?4413.Name the lobes of the right and left lungs4514.Name the first three bronchial divisions4615.What are the broncho-pulmonary segments?4716.What is the cardiac notch and lingula?4817.Name the structures which pass in and out of the lung hilum and their roughpositions in relation to each other4918.Name the adjacent structures which leave impressions in the right and left lungs5019.The upper lobe of either lung is the area above which rib/costal cartilage?5120.Between which ribs does the middle lobe of the right lung lie?5221.The base of the lung at the mid-clavicular line is at (i) which rib, (ii) whilst theparietal pleura stretches further down to which rib?5343 Because the bifurcation of the trachea is asymmetrical and the right bronchus is more vertically oriented44 The carina is the V shaped ring of cartilage where the trachea terminates into the 2 bronchi at T445 Right has 3 lobes (upper, middle and lower) the left has 2 (upper and lower) as space taken up by theheart on the left side.46 2x main bronchi, lobar bronchi (to each lobe of each lung), tertiary/segmental bronchi.47 10 ʻterritoriesʼ within each lung, so named because they are supplied by corresponding divisions of arterialsupply.48 Cardiac notch = the notch in the left lung made by the the heart, Lingula = the part of the lower lobe whichprojects in front of the heart49 Bronchus (top), pulmonary artery (middle) pulmonary veins (bottom), pulmonary ligament (surrounds thelung root).50 Right lung: heart, SVC and IVC, azygos vein, 1st rib, oesophagus. Left lung: Aortic arch and descendingaorta, 1st rib, left subclavian artery51 4th rib (approximately the level of the nipple in males)52 4th-6th (lower lobe is posterior to middle), the division is called the oblique fissure53 6th and 8th ribs
  6. 6. 22.And the same for the mid-axilliary line (side)?5423.Based on the answer to (22), a chest drain to treat a pneumothorax (fluid in thepleural cavity) can be inserted through which intercostal space?5524. Label the positions A-D on the diagram interms of what part of the lung you would belistening to if you placed a stethoscope there5625. Which intercostal spaces posteriorly wouldyou ascultate to hear (i) apex of the left lung,(ii) superior lobe of the left lung, (iii) inferiorlobe of the left lung5726.Which nerves innervate the sensitivediaphragmatic and mediastinal parietal pleura?58Anatomy of the Heart 11. Describe where on the chest you would ascultate to listen to the (i) right atrium,(ii) right ventricle (iii) left atrium (iv) left ventricle592. Name the 3 layers of the pericardium603. What are the attachments of the fibrous layer of pericardium?614. Which layers of the pericardium are sensitive and supplied by the phrenic nerves?6254 8th and 10th ribs (further down at sides of thorax)55 9th (so between ribs 9 and 10)56 A = apex of the right lung (note this is above the clavicle), B = 2nd intercostal space, Superior/upper lobeof right lung, C = 4th intercostal space, middle lobe, D = 6th intercostal space, lower lobe57 (i) apex of the left lung = above first rib (ii) superior lobe of the left lung = 2nd (iii) inferior lobe of the leftlung = 7th58 phrenic nerves originating from C3,4,5, so pain from this region is often felt over the shoulder59 Right atrium = 3rd costal cartilage, Right ventricle = 6th costal cartilage, Left atrium = 2nd intercostalspace, Left ventricle = 5th-7th intercostal spaces60 Fibrous, parietal and visceral61 Inferiorly to the central tendon of the diaphragm, anteriorly to the chest wall and superiorly and posteriorlyto the adventitia62 The parietal and fibrous but not the visceral
  7. 7. 5. What is the cardiac skeleton?636. Left heart and right heart refer to the embryological position of the heart, whatdirection do they face in adulthood?647. What is the crista terminalis?658. What are the 3 openings into the right atrium?669. What are the differences in nature of the wall behind the crista and the wall infront of it?6710.What is the name of the depression in the septal wall of the right atrium whichcloses at birth?6811.What are the two valves adjacent to the right ventricle?6912.What is the purpose of the chordae tendonae and the papillary muscles in theventricles?7013.Which valve of the left ventricle is the most likely to become defective?7114.What are the key differences between the fetal heart and the developed heart?72Anatomy of the Heart 2 and Superior Mediastinum63 The septum between the atria/ventricles and left/right into which the heart contracts. This needs to befibrous and stiff for the heart to create pressure.64 The right side of the apex is in contact with the diaphragm so is facing downwards, the left is facing theaorta so upwards and to the left.65 Vertical ridge running between the SVC and IVC. At the upper end is the SAN so it has an important role inelectrical conduction across the heart.66 SCV, IVC and coronary sinus (the main vein draining the heart muscle itself)67 The wall in front of the crista terminalis is muscular, the wall behind the crista terminalis is smooth.68 Fossa Ovalis69 Tricuspid and pulmonary valves70 Anchors for the heart valves, they need to resist a high pressure system.71 Mitral valve - between left atrium and left ventricle72 Foramen ovale closes, because the lung beds are closed in the fetus, the pressure through the pulmonarysystem is high, so the right heart pressure is higher than the left, this is reversed following birth. The ductconnecting the pulmonary trunk to the aorta also closes at birth. Failure for either the foramen ovale orducturs arteriosus to close is problematic after birth.
  8. 8. 1. What are the 3 layers of the heart wall?732. Which direction do the ventricles contract?743. Name the 2 principal branches of the coronary arteries?754. Which areas of the heart are supplied by each of these branches?765. What does it mean for coronary circulation to be right or left dominant?776. Where would ‘referred pain’ from a heart attack be felt and why?787. Which intercostal spaces would you ascultate to hear (i) the aortic valve (ii) thepulmonary valve (iii) mitral valve (iv) tricuspid valve798. With no or defective chordae tendonae present what would the direction ofblood flow be during ventricular systole?809. List the sub-divisions of the mediastinum8110.List the main contents of the mediastinum8273 Endocardium, myocardium and epicardium74 From the apex of the heart upwards, think : the aorta is at the top of the heart75 Two coronary arteries arise from the right (front) and left (left/behind) aortic sinuses respectively.76 Right coronary = SAN, AVN and right heart, Left coronary = septum, left and right bundles.77 Coronary dominance is defined by the vessel that gives rise to the posterior descending artery. Rightdominancy (50% of people) is where the right coronary gives rise to the posterior descending artery, leftdominance is if it is the left coronary (in 20% of people).78 Pain in the chest, arm or below the sternum, discomfort in the back, jaw, throat. All related to sympatheticafferents.79 (i) the aortic valve = 2nd intercostal space, right of sternum (ii) the pulmonary valve = 2nd intercostalspace left of sternum (iii) mitral valve = 5th intercostal space 6-9cm away from sternum in left (iv) tricuspidvalve = 5th costal margin80 Blood would flow back into the atria as well as the ventricles81 Mediastinum is the space between the lungs within the thoracic cavity, it is bounded anteriorly by thesternum and posteriorly by the vertebral column. It is subdivided into a superior (upper) and inferior (lower)mediastinum by the sternal angle (where the manubrium joints the body of the sternum). The inferior partcan be subdvided again into anterior, middle and posterior.82 Remnants of the thymus gland, great veins, arch of the aorta, lower part of the trachea and theoesophagus, the heart (middle mediastinum).
  9. 9. 11.What is the thymus?8312.Name the branches of the thoracic aorta8413.Name the great veins85Inferior Mediastinum1. Which structure appears as a white circle positioned slightly to the left on amediastinal x-ray.2. Which mediastinal structures lie immediately posterior to the left atrium?863. Label structures A-D on the diagramshowing an MRI scan of T4?874.Where are the constrictions left byadjacent structures to the oesophagus?885.Which veins drain into the azygos veinrunning down the back of the thoracic cage?896.Where is the azygos vein in relation to theoesophagus and the thoracic duct?9083 A gland that plays an important role in the development of the immune system in infants but regresses withdevelopment during puberty.84 The arch of the aorta has 3 branches (Brachiocephalic, left common carotid, subclavian). All goingupwards to neck and shoulders.85 The main vein of the thorax is the SVC, the right and left brachiocephalic veins channel into it, which arethemselves formed by the junctions of the internal jugular veins and the subclavian veins.86 Oesophagus and trachea. The aorta arches backwards and to the left at the sternal angle, so it goesbehind these two structures.87 A - branches of thoracic aorta (Brachiocephalic, left common carotid, subclavian), B - Esophagus, C -Trachea (note dark colouring because full of air, D -SVC88 From top to bottom: Cricoid cartilage of the larynx (C6), arch of the aorta, left main bronchus, left atrium,entry through the diaphragm (T12)89 Hemiazygos (lower left side of the thorax), accessory hemiazygos (upper left side), these cross thevertebra to reach the azygos vein on the right hand side which drains the entire right side.90 Azygos vein runs posterior to the oesophagus and to the right of the thoracic duct (which runs up along thespinal column)
  10. 10. 7. Which vertebral levels give rise to the phrenic nerves?918. Which brain centres control the phrenic nerves?929. How does the right phrenic nerve pass the following structures: right scalenusanterior muscle, SVC and right border of the heart?9310.What is the course of the left phrenic nerve in relation to the followingstructures: 1st rib, aortic arch, left atrium and ventricle?9411.What areas are supplied by the vagus in the neck?9512.Where do the pulmonary plexus and cardiac plexus branch off from the vagusnerve?9613.Explain the differences between somatic afferents and somatic efferents of thevagus nerve?9714.And the differences between parasympathetic afferents and efferents?9815.Where do sympathetic nerves of the thorax originate?9916.Which vertebral levels do the superior, middle and inferior ganglions of thethoracic sympathetic nerves originate?10017.Which vertebral levels give rise to the fibres of the cardiac sympathetic plexus?10191 C3,4,& 5 remember that any interruption above this point can also stop breathing92 Respiratory centres in the pons and medulla93 In front of the right scalenus anterior, to the side of the SVC and over the right border of the heart94 Deep to the 1st rib, to the left of the aortic arch and down the outside of the left heart95 The larynx and trachea, initiate the cough reflex96 Pulmonary plexus at the level of the bifurcation of the trachea (T4, at the carina of the trachea). Cardiacplexus at the aortic arch.97 Somatic efferents are skeletomotor muscles of the pharynx, larynx and upper oesophagus. Somaticafferents are general sensory, pain, touch and temperature sensation.98 Afferents detect distention of the lung and irritation of intra pulmonary tissues. Baroreceptors andchemoreceptors. Efferents cause the effects so increase mucous secretion and contract smooth muscle ofthe respiratory tract, slow heart rate etc.99 In the lateral horns of spinal nerves T1-2100 superior C1-C4, middle C5-6, inferior C7-T1101 T1-4
  11. 11. 18. What factors other than autonomic stimulation might influence heart rate?10219.Name the locations of the chemoreceptors and baroreceptors10320.Where is the carotid body?10421.Which nerves are involved in baroreception and chemoreception?105102 Drugs (e.g. anesthetics decrease HR), peripheral vasodilation decreases blood pressure and producesreflex tachycardia, increased blood Co2 increases HR,103 Chemoreceptors located at the bifurcation of the common carotid artery and in the aortic bodies.Baroreceptors located in the bifurcation of the common carotid artery and on the aortic arch104 A small nodule located on the common carotid artery just above the carotid baroreceptors105 Carotid baroreceptors innervated by the glossopharyngeal and vagus nerves, aortic just by the vagusnerve.