AnatomyThe Chest Wall and Thoracic Apertures

1. List the layers of the thoracic wall1

2. What is supplied by the (i) posterior and (ii) anterior rami?2

3. Where is the Angle of Louis?3

4. Why can the first rib not be palpated?4

5. Name the bones that make up the thoracic cage?5

6. In what way are the ribs angled to assist forced breathing?6

7. Which ribs are typical and atypical and why?7

8. Define the ‘thoracic inlet’ and ‘thoracic outlet’?8

9. List the structures that pass through the thoracic inlet?9

10.What are the attachments of the diaphragm?10

1 Skin, Superficial Fascia, Serratus Anterior (External Intercostal), Internal Intercostal, Innermost Intercostal, Parietal Pleura and Visceral Pleura

2 Anterior supply the internal intercostal muscles, sympathetic nerves to skin and blood vessels (via thoracic trunk), and parietal pleura, Posterior supply post vertebral

3 Where the 2nd rib attaches to the sternum, at the joint between the manubrium (top of sternum) and body of the sternum, known as the sternal angle.

4 Because it lies deep to the clavicle

5 Sternum (Manubrium, body and Xiphisternum), Ribs 1-7 (attached to sternum via cartilage), 8-10 (attached to 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 breathing

7 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 (because they 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 thoracic outlet (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 jugular and subclavian vein. (Compressed in thoracic OUTLET syndrome)

10 The ribs (including 11th and 12th) all the way round, and the costal cartilage.

11.Where are the attachments of the scalene and sternocleidomastoid muscles?11

12.What and where is the phrenic angle?12

13.Which arteries supply the chest wall?13

14. Label the posterior thoracic venous drainage numbered 1-4 on the diagram14

15.Which veins drain the chest wall anteriorly?15

16.Which areas do the (i) superficial and (ii) deep thoracic lymphatics mostly travel towards?16

Anatomy of Breathing

1. What is a URTI?17

2. At which part of the lung are the visceral pleura and parietal pleura continuous?18

3. Which layer of the pleural membrane is sensitive and which is not?19

4. What is the function of pleural fluid?20

5. Which two factors contribute to the elasticity and surface tension of the lungs?21

11 Scalene muscles stabilise the neck and are attached to the cervical vertebrae and 2nd rib. The sternocleidomastoid (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 lung tissue 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 vein

15 Veins allied to the internal thoracic arteries which follow the same route.

16 Superficial = axilla (armpit), Deep = thoracic duct

17 Upper Respiratory Tract Infection - A viral infection located in the respiratory tract anywhere above the vocal cords.

18 Hilum (top) of ling

19 Parietal only

20 Lubrication during movement of the chest cavity

21 Surfactant (produced by type II pneumocytes), and elastic tissue in the lung connective tissue

6. What causes the pleural cavity to have a negative pressure?22

7. Why is an upright posture better than a slouched posture for a patient in respiratory distress?23

8. Where do the IVC, oesophagus and abdominal aorta pass through the diaphragm?24

9. Which vertebrae give rise to the phrenic nerves that innervate the diaphragm?25

10.List the layers of muscles in the intercostal space, what are their functions?26

11.What is flail chest?27

12.Define ‘inspiratory muscles’ and ‘expiratory muscles’ and list a few examples of each?28

13.Which muscles are involved in quiet inspiration?29

14.Which muscles are involved in forced inspiration?30

15.Which muscles are involved in quiet exhalation?31

22 Pressure in pleural cavity is below atmospheric pressure purely because of surface tension created by pleural fluid, think of pulling apart two wet plates

23 Gravity assists the diaphragm by causing descent of the heavy abdominal organs, when lying flat the rib cage 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 the back, oesophagus through the ʻright crusʼ which acts as a sphincter to prevent stomach being sucked back into thorax. The IVC passes through the cartilaginous section of the diaphragm in the centre (caval opening).

25 C3,4 and 5 keep you alive

26 External intercostal muscle (forwards and downwards), internal intercostal muscle, innermost intercostal muscle. 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 it bellowing out during expiration. The intercostals normally contract during inspiration and expiration to maintain 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 forced breathing), rectus abdominis (expiratory)

29 Diaphragm, scalene (stabilises 1st rib), intercostals (to prevent ʻflail chestʼ)

30 Scalenes and sternocleidomastoid, pectoralis major and minor, intercostals, quadratus lumboram

31 Quiet exhalation can be done passively due to elastic recoil of lungs and gravity, although commonly the diaphragm and intercostals are involve for stabilizing.

16.Which muscles are involved in forced exhalation?32

Respiratory Tract, Lungs and Pleurae

1. What type of epithelium is unique to the respiratory tract?33

2. How do the nasal cavities function as a protective mechanism?34

3. Which nerve supplies the bronchoconstrictor muscle?35

4. What is the function of the larynx?36

5. What is the piriform fossae?37

6. What are the potential hazards of performing an emergency laryngotomy?38

7. What are the 3 cartilage structures that make up the larynx?39

8. Which muscle can modify the diameter of the trachea?40

9. What is the basic structure of the trachea and early bronchi?41

10.At which vertebral level does the trachea bifurcate into two bronchi?42

32 Abdominals, intercostals, latissimus dorsi.

33 Pseudo stratified columnar ciliated epithelium, specifically the mucocilliary escalator which consists of a ʻgelʼ 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 nasal cavities secrete antibiotic enzymes. Mucous environment traps bacteria and particles.

35 Vagal, because parasympathetic stimulation causes bronchoconstriction. The vagus nerve also responds to stretch, chemical environment and irritant receptors to initiate the cough reflex. The cough reflex involved the medulla.

36 Primarily as a sphincter of the airway, its superior margin is bounded by the aryepiglottic muscles which close the airway itself.

37 It is a channel either side of the laryngeal inlet. The inlet is raised allowing fluids to run into the piriform fossae.

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 cartilage

40 C shaped rings of smooth muscle

41 Mucocilliary epithelium inside C shaped rings of hyaline cartilage interspersed with smooth (trachielis) muscle

42 T4 at expiration (when pushed up)

11. Why is an inhaled foreign object 80% more likely to enter the right lung?43

12.What and where is the carina?44

13.Name the lobes of the right and left lungs45

14.Name the first three bronchial divisions46

15.What are the broncho-pulmonary segments?47

16.What is the cardiac notch and lingula?48

17.Name the structures which pass in and out of the lung hilum and their rough positions in relation to each other49

18.Name the adjacent structures which leave impressions in the right and left lungs50

19.The upper lobe of either lung is the area above which rib/costal cartilage?51

20.Between which ribs does the middle lobe of the right lung lie?52

21.The base of the lung at the mid-clavicular line is at (i) which rib, (ii) whilst the parietal pleura stretches further down to which rib?53

43 Because the bifurcation of the trachea is asymmetrical and the right bronchus is more vertically oriented

44 The carina is the V shaped ring of cartilage where the trachea terminates into the 2 bronchi at T4

45 Right has 3 lobes (upper, middle and lower) the left has 2 (upper and lower) as space taken up by the heart 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 arterial supply.

48 Cardiac notch = the notch in the left lung made by the the heart, Lingula = the part of the lower lobe which projects in front of the heart

49 Bronchus (top), pulmonary artery (middle) pulmonary veins (bottom), pulmonary ligament (surrounds the lung root).

50 Right lung: heart, SVC and IVC, azygos vein, 1st rib, oesophagus. Left lung: Aortic arch and descending aorta, 1st rib, left subclavian artery

51 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 fissure

53 6th and 8th ribs

22.And the same for the mid-axilliary line (side)?54

23.Based on the answer to (22), a chest drain to treat a pneumothorax (fluid in the pleural cavity) can be inserted through which intercostal space?55

24. Label the positions A-D on the diagram in terms of what part of the lung you would be listening to if you placed a stethoscope there56

25. Which intercostal spaces posteriorly would you ascultate to hear (i) apex of the left lung, (ii) superior lobe of the left lung, (iii) inferior lobe of the left lung57

26.Which nerves innervate the sensitive diaphragmatic and mediastinal parietal pleura?58

Anatomy of the Heart 1

1. Describe where on the chest you would ascultate to listen to the (i) right atrium, (ii) right ventricle (iii) left atrium (iv) left ventricle59

2. Name the 3 layers of the pericardium60

3. What are the attachments of the fibrous layer of pericardium?61

4. Which layers of the pericardium are sensitive and supplied by the phrenic nerves?62

54 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 lobe of right lung, C = 4th intercostal space, middle lobe, D = 6th intercostal space, lower lobe

57 (i) apex of the left lung = above first rib (ii) superior lobe of the left lung = 2nd (iii) inferior lobe of the left lung = 7th

58 phrenic nerves originating from C3,4,5, so pain from this region is often felt over the shoulder

59 Right atrium = 3rd costal cartilage, Right ventricle = 6th costal cartilage, Left atrium = 2nd intercostal space, Left ventricle = 5th-7th intercostal spaces

60 Fibrous, parietal and visceral

61 Inferiorly to the central tendon of the diaphragm, anteriorly to the chest wall and superiorly and posteriorly to the adventitia

62 The parietal and fibrous but not the visceral

5. What is the cardiac skeleton?63

6. Left heart and right heart refer to the embryological position of the heart, what direction do they face in adulthood?64

7. What is the crista terminalis?65

8. What are the 3 openings into the right atrium?66

9. What are the differences in nature of the wall behind the crista and the wall in front of it?67

10.What is the name of the depression in the septal wall of the right atrium which closes at birth?68

11.What are the two valves adjacent to the right ventricle?69

12.What is the purpose of the chordae tendonae and the papillary muscles in the ventricles?70

13.Which valve of the left ventricle is the most likely to become defective?71

14.What are the key differences between the fetal heart and the developed heart?72

Anatomy of the Heart 2 and Superior Mediastinum

63 The septum between the atria/ventricles and left/right into which the heart contracts. This needs to be fibrous 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 the aorta 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 in electrical 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 Ovalis

69 Tricuspid and pulmonary valves

70 Anchors for the heart valves, they need to resist a high pressure system.

71 Mitral valve - between left atrium and left ventricle

72 Foramen ovale closes, because the lung beds are closed in the fetus, the pressure through the pulmonary system is high, so the right heart pressure is higher than the left, this is reversed following birth. The duct connecting the pulmonary trunk to the aorta also closes at birth. Failure for either the foramen ovale or ducturs arteriosus to close is problematic after birth.

1. What are the 3 layers of the heart wall?73

2. Which direction do the ventricles contract?74

3. Name the 2 principal branches of the coronary arteries?75

4. Which areas of the heart are supplied by each of these branches?76

5. What does it mean for coronary circulation to be right or left dominant?77

6. Where would ‘referred pain’ from a heart attack be felt and why?78

7. Which intercostal spaces would you ascultate to hear (i) the aortic valve (ii) the pulmonary valve (iii) mitral valve (iv) tricuspid valve79

8. With no or defective chordae tendonae present what would the direction of blood flow be during ventricular systole?80

9. List the sub-divisions of the mediastinum81

10.List the main contents of the mediastinum82

73 Endocardium, myocardium and epicardium

74 From the apex of the heart upwards, think : the aorta is at the top of the heart

75 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. Right dominancy (50% of people) is where the right coronary gives rise to the posterior descending artery, left dominance 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 sympathetic afferents.

79 (i) the aortic valve = 2nd intercostal space, right of sternum (ii) the pulmonary valve = 2nd intercostal space left of sternum (iii) mitral valve = 5th intercostal space 6-9cm away from sternum in left (iv) tricuspid valve = 5th costal margin

80 Blood would flow back into the atria as well as the ventricles

81 Mediastinum is the space between the lungs within the thoracic cavity, it is bounded anteriorly by the sternum 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 part can 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 the oesophagus, the heart (middle mediastinum).

11.What is the thymus?83

12.Name the branches of the thoracic aorta84

13.Name the great veins85

Inferior Mediastinum

1. Which structure appears as a white circle positioned slightly to the left on a mediastinal x-ray.

2. Which mediastinal structures lie immediately posterior to the left atrium?86

3. Label structures A-D on the diagram showing an MRI scan of T4?87

4.Where are the constrictions left by adjacent structures to the oesophagus?88

5.Which veins drain into the azygos vein running down the back of the thoracic cage?89

6.Where is the azygos vein in relation to the oesophagus and the thoracic duct?90

83 A gland that plays an important role in the development of the immune system in infants but regresses with development during puberty.

84 The arch of the aorta has 3 branches (Brachiocephalic, left common carotid, subclavian). All going upwards to neck and shoulders.

85 The main vein of the thorax is the SVC, the right and left brachiocephalic veins channel into it, which are themselves 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 goes behind 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 -SVC

88 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 the vertebra 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 the spinal column)

7. Which vertebral levels give rise to the phrenic nerves?91

8. Which brain centres control the phrenic nerves?92

9. How does the right phrenic nerve pass the following structures: right scalenus anterior muscle, SVC and right border of the heart?93

10.What is the course of the left phrenic nerve in relation to the following structures: 1st rib, aortic arch, left atrium and ventricle?94

11.What areas are supplied by the vagus in the neck?95

12.Where do the pulmonary plexus and cardiac plexus branch off from the vagus nerve?96

13.Explain the differences between somatic afferents and somatic efferents of the vagus nerve?97

14.And the differences between parasympathetic afferents and efferents?98

15.Where do sympathetic nerves of the thorax originate?99

16.Which vertebral levels do the superior, middle and inferior ganglions of the thoracic sympathetic nerves originate?100

17.Which vertebral levels give rise to the fibres of the cardiac sympathetic plexus?101

91 C3,4,& 5 remember that any interruption above this point can also stop breathing

92 Respiratory centres in the pons and medulla

93 In front of the right scalenus anterior, to the side of the SVC and over the right border of the heart

94 Deep to the 1st rib, to the left of the aortic arch and down the outside of the left heart

95 The larynx and trachea, initiate the cough reflex

96 Pulmonary plexus at the level of the bifurcation of the trachea (T4, at the carina of the trachea). Cardiac plexus at the aortic arch.

97 Somatic efferents are skeletomotor muscles of the pharynx, larynx and upper oesophagus. Somatic afferents are general sensory, pain, touch and temperature sensation.

98 Afferents detect distention of the lung and irritation of intra pulmonary tissues. Baroreceptors and chemoreceptors. Efferents cause the effects so increase mucous secretion and contract smooth muscle of the respiratory tract, slow heart rate etc.

99 In the lateral horns of spinal nerves T1-2

100 superior C1-C4, middle C5-6, inferior C7-T1

101 T1-4

18. What factors other than autonomic stimulation might influence heart rate?102

19.Name the locations of the chemoreceptors and baroreceptors103

20.Where is the carotid body?104

21.Which nerves are involved in baroreception and chemoreception?105

102 Drugs (e.g. anesthetics decrease HR), peripheral vasodilation decreases blood pressure and produces reflex 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 arch

104 A small nodule located on the common carotid artery just above the carotid baroreceptors

105 Carotid baroreceptors innervated by the glossopharyngeal and vagus nerves, aortic just by the vagus nerve.