4- Thorax MSQs Only (1)

Question 1

2 of 73
Which of the following fascial structures encases the apex of the lungs?

Answer 1

Sibsons fascia

Sibson’s fascia overlies the apices of both lungs

The suprapleural fascia (Sibson’s fascia) runs from C7 to the first rib and overlies the apex of both lungs.It lies between the parietal pleura and the thoracic cage.

Question 2

3 of 73

A 5 year old boy is playing with some small ball bearings. Unfortunately, he inhales one. To which of the following lung regions is the ball most likely to settle?

Answer 2

Right lower lobe

As the most dependent part of the right lung a small object is most likely to lodge here. Most objects will preferentially enter the right lung owing to the angle the right main bronchus takes from the trachea.

Question 3

4 of 73

A patient presents with superior vena caval obstruction. How many collateral circulations exist as alternative pathways of venous return?

Answer 3

Four

There are 4 collateral venous systems:
· Azygos venous system
. Internal mammary venous pathway
. Long thoracic venous system with connections to the femoral and vertebral veins (2 pathways)

Despite this, venous hypertension still occurs.

Question 4

Question 5 of 73

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?

Answer 4

Subclavian vein

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).

Question 5

6 of 73

Where are the greatest proportion of musculi pectinati found?

Answer 5

Right atrium

The musculi pectinati are found in the atria, hence the reason that the atrial walls in the right atriumare 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.

Question 6

7 of 73

Which of the following statements relating to the right phrenic nerve is false?

Answer 6

It lies deep to the prevertebral layer of deep cervical fascia

Crosses posterior to the 2nd part of the subclavian artery (right)
It runs on the anterior surface of the anterior scalene muscle

On the right side it leaves the mediastinum via the vena cava hiatus at a level of T8

Question 7

8 of 73
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?

Answer 7

Azygos vein

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.

Question 8

9 of 73

An individual is noted to have a left sided superior vena cava. By which pathway is blood from this system most likely to enter the heart?

Answer 8

Via the coronary sinus

Persistent left superior vena cava is the most common anomaly of the thoracic venous system. It is prevalent in 0.3% of the population and is a benign entity of failed involution during embryogenesis.

Question 9

10 of 73

Which of the structures listed below are not located within the mediastinum?

Answer 9

Vertebral bodies

The vertebral bodies lie outside of the mediastinum, as do the lungs.

Question 10

12 of 73

A cervical rib is due to which of the following?

Answer 10

Elongation of the transverse processes of the 7th cervical vertebra

Cervical ribs occur as a result of the elongation of the transverse process of the 7th cervical
vertebra. It is usually a fibrous band that attaches to the first thoracic rib.

Question 11

11 of 73

A 22 year old man is stabbed in the chest at the level of the junction between the sternum and manubrium. Which structure is at greatest risk?

Answer 11

Aortic arch

At the level of the Angle of Louis (Manubriosternal angle), is the surface marking for the aortic arch.
The oesophagus is posteriorly located and at less risk.

Question 12

14 of 73

Inspection of the left ventricle reveals all except which of the following?

Answer 12

Conus arteriosus

The conus arteriosus (infundibulum) is the smooth walled outflow tract of the right ventricle leading to the pulmonary trunk.

Question 13

15 of 73

A 23 year old lady with troublesome axillary hyperhidrosis is undergoing a thorascopic sympathectomy to treat the condition. Which of the following structures will need to be divided to access the sympathetic trunk?

Answer 13

Parietal pleura

The sympathetic chain lies posterior to the parietal pleura. During a thorascopic sympathetomy this structure will need to be divided. The intercostal vessels lie posteriorly. They may be damaged withtroublesome bleeding but otherwise are best left alone as deliberate division will not improve surgical access

Question 14

19 of 73

Following an oesophagogastrectomy the surgeons will anastomose the oesophageal remnant to the stomach, which of the following is not part of the layers that comprise the oesophageal wall?

Answer 14

Serosa

The oesophageal wall lacks the serosa layer
The wall lacks a serosa which can make the wall hold sutures less securely.

Question 15

21 of 73

Where is the centre of the ‘safe triangle’ for chest drain insertion located?

Answer 15

5th intercostal space, mid axillary line

‘Safe Triangle’ for chest drain insertion:
5th intercostal space, mid axillary line

Question 16

24 of 73

A 63 year old man is undergoing a coronary artery bypass procedure. During the median sternotomy which structure would routinely require division?

Answer 16

Interclavicular ligament

The interclavicular ligament lies at the upper end of a median sternotomy and is routinely divided to provide access. The pleural reflections are often encountered and should not be intentionally divided, if they are, then a chest drain will need to be inserted on the affected side as collections may then accumulate in the pleural cavity. Other structures encountered include the pectoralis major muscles, again if the incision is truly midline then these should not require formal division. The close relationship of the brachiocephalic vein should be borne in mind and it should be avoided, iatrogenicinjury to this structure will result in considerable haemorrhage.

Question 17

25 of 73

What are the boundaries of the ‘safe triangle’ for chest drain insertion?

Answer 17

Bounded by latissimus dorsi, pectoralis major, line superior to the nipple and apex at the axilla

Question 18

26 of 73

A 34 year old male is being examined in the pre-operative assessment clinic. A murmur is identified in the 4th intercostal space just next to the left side of the sternum. From where is it most likely tohave originated?

Answer 18

Tricuspid valve

The tricuspid valve is generally referred to being best auscultated adjacent to the sternum. The plane of projected sound from the mitral area is best heard in the region of the cadiac apex.

Question 18

27 of 73

During an Ivor Lewis Oesophagectomy for carcinoma of the lower third of the oesophagus which structure is divided to allow mobilisation of the oesophagus?

Answer 18

Azygos vein

The azygos vein is routinely divided during an oesophagectomy to allow mobilisation. It arches anteriorly to insert into the SVC on the right hand side.

Question 19

28 of 73

Which of the following statements relating to the root of the neck is false?

Answer 19

The subclavian artery arches over the first rib anterior to scalenus anterior

The subclavian artery lies posterior to scalenus anterior, the vein lies in front. Sibson’s fascia is
another name for the suprapleural membrane.

Question 19

29 of 73

Which of the following are not generally supplied by the right coronary artery?

Answer 19

The circumflex artery

The circumflex artery is generally a branch of the left coronary artery.

Question 20

30 of 73

A patient has a chest drain insertion. There is fresh blood at the chest drain insertion area. Which vessel has been damaged?

Answer 20

Intercostal artery

The intercostal vein is more superior than the artery and is thus slightly less susceptible to injury.

Within the intercostal spaces there are thin, strong muscles, intercostal vessels, nerves and
lymphatics. There are 3 intercostal muscle layers corresponding to the lateral abdominal wall; external, internal, innermost intercostals. At the mid axillary line there are thin intracostals which is an extension of the internal intercostal muscle. In each intercostal space lies the neurovascular bundle, comprising, from superior to inferiorly; the posterior intercostal vein, artery and nerve, lying protected in the subcostal groove of the rib above and situated between the second and third layer of the intercostal muscles. These blood vessels anastomose anteriorly with the anterior intercostal vessels, which arise from the internal thoracic artery and vein.

Question 21

31 of 73
A 64 year old man has a suspected lymphoma and lymph node biopsy from the posterolateral aspect of the right neck is planned. Which of the nerves listed is at greatest risk?

Answer 21

Accessory

The accessory nerve has a superficial course and is easily injured. It lies under platysma and may be divided during the early part of the procedure.

Question 22

32 of 73

A 34 year old lady undergoes a thyroidectomy for Graves disease. Post operatively she develops a tense haematoma in the neck. In which of the following fascial planes will it be contained?

Answer 22

Pretracheal fascia

The pretracheal fascia encloses the thyroid and is unyielding. Therefore tense haematomas can
develop.

Question 23

33 of 73

Which of the following is not considered a major branch of the descending thoracic aorta?

Answer 23

Inferior thyroid artery

The inferior thyroid artery is usually derived from the thyrocervical trunk, a branch of the subclavian
artery.

Question 24

34 of 73

A 53 year old man with a carcinoma of the lower third of the oesophagus is undergoing an oesophagogastrectomy. As the surgeons mobilise the lower part of the oesophagus, where are they most likely to encounter the thoracic duct?

Answer 24

Posterior to the oesophagus

The thoracic duct lies posterior to the oesophagus and passes to the left at the level of the Angle of Louis. It enters the thorax at T12 together with the aorta.

Question 24

35 of 73

Which of the following pairings are incorrect?

Answer 24

Termination of dural sac and L4

Vena cava T8 (eight letters)
Oesophagus T10 (ten letters)
Aortic hiatus T12 (twelve letters)

It terminates at S2, which is why it is safe to undertake an LP at L4/5 levels. The spinal cord itself terminates at L1.

Question 24

36 of 73

A 72 year old man presents with haemoptysis and undergoes a bronchoscopy. The carina is noted to be widened. At which level does the trachea bifurcate?

Answer 24

T5

The trachea bifurcates at the level of the fifth thoracic vertebra. Or the sixth in tall subjects.

Question 25

37 of 73

The following structures are closely related to the brachiocephalic artery except:

Answer 25

Trachea posteriorly
Right brachiocephalic vein
Inferior thyroid vein
Right recurrent laryngeal nerve ( Right )
Non of above

There is no brachiocephalic artery on the left, however the left brachiocephalic vein lies anteriorly to the roots of all the 3 great arteries (including the brachiocephalic artery). The right recurrent laryngeal nerve has no relation to the brachiocephalic artery.

Question 26

38 of 73

Which structure is least likely to be found at the level of the sternal angle?

Answer 26

Left brachiocephalic vein

The left brachiocephalic vein lies posterior to the manubrium, at the level of its upper border. The sternal angle refers to the transition between manubrium and sternum and therefore will not includethe left brachiocephalic vein.

Question 27

40 of 73

A 43 year old man is reviewed in the clinic following a cardiac operation. A chest x-ray is performed and a circular radio-opaque structure is noted medial aspect of the 4th intercostal space on the left.Which of the following procedures is the patient most likely to have undergone?

Answer 27

Mitral valve replacement with metallic valve

Question 28

41 of 73

A 23 year old man is shot in the chest during a robbery. The left lung is lacerated and is bleeding. An emergency thoracotomy is performed. The surgeons place a clamp over the hilum of the left lung.
Which of the following structures lies most anteriorly at this level?

Answer 28

Phrenic nerve

The phrenic nerve lies anteriorly at this point. The vagus passes anteriorly and then arches
backwards immediately superior to the root of the left bronchus, giving off the recurrent laryngeal nerve as it does so.

Question 29

43 of 73

During the repair of an atrial septal defect the surgeons note that blood starts to leak from the coronary sinus. Which structure forms the largest tributary of the coronary sinus?

Answer 29

Great cardiac vein

The great cardiac vein runs in the anterior interventricular groove, and is the largest tributary of the coronary sinus. The thebesian veins drain into the heart directly.

Question 30

44 of 73

A man is stabbed in the chest to the right of the manubriosternal angle. Which structure is least likely to be injured in this case?

Answer 30

Right recurrent laryngeal nerve

The right recurrent laryngeal nerve branches off the right vagus more proximally and arches
posteriorly round the subclavian artery. So of the structures given it is the least likely to be injured.

Question 31

45 of 73

Which of the following types of epithelium lines the lumenal surface of the normal oesophagus?

Answer 31

Non keratinised stratified squamous epithelium

The oesphagus is lined by non keratinised stratified squamous epithelium. Changes to glandular type epithelium occur as part of metaplastic processes in reflux.

Question 32

48 of 73

A 23 year old man is due to undergo a mitral valve repair for mitral regurgitation. Which of the following is a feature of the mitral valve?

Answer 32

Its closure is marked by the first heart sound

The mitral valve is best auscultated over the cardiac apex, where its closure marks the first heart sound. It has only two cusps. These are attached to chordae tendinae which themselves are linked to the wall of the ventricle by the papillary muscles.

Question 32

46 of 73
The oesophagus is constricted at the following levels apart from:

Answer 32

Lower oesophageal sphincter

Constrictions of the oesophagus : ABCD
A- Arch of the Aorta
B- Left main Bronchus
C- Cricoid Cartilage
D- Diaphragmatic Hiatus

The oesophagus is not constricted at the level of the lower oesophageal sphincter.

Question 33

49 of 73

Which of the following is true in connection with the phrenic nerves?

Answer 33

They both lie anterior to the hilum of the lungs

C3,4,5
Keeps the diaphragm alive!

They both lie anterior to the hilum of the lung. The phrenic nerves have both motor and sensory functions. For this reason sub diaphragmatic pathology may cause referred pain to the shoulder.

Question 33

50 of 73

Which of the following overlies the outer muscular layer of the intrathoracic oesophagus?

Answer 33

Loose connective tissue

The oesophagus has no serosal covering and hence holds sutures poorly. The Auerbach’s and Meissner’s nerve plexuses lie in between the longitudinal and circular muscle layers and submucosally. The sub mucosal location of the Meissner’s nerve plexus facilitates its sensory role.

Question 34

Question 50 of 73

Which of the following overlies the outer muscular layer of the intrathoracic

Answer 34

Loose connective tissue

The oesophagus has no serosal covering and hence holds sutures poorly. The Auerbach’s and Meissner’s nerve plexuses lie in between the longitudinal and circular muscle layers and submucosally. The sub mucosal location of the Meissner’s nerve plexus facilitates its sensory role.

Question 35

51 of 73

Which nerve lies medially on the thyroid gland, in the groove between the oesophagus and trachea?

Answer 35

Recurrent laryngeal nerve

The recurrent laryngeal nerve may be injured at this site during ligation of the inferior thyroid artery.

Question 36

52 of 73

How many fissures are present within the right lung?

Answer 36

TWO

The right lung has an oblique and horizontal fissure. The upper oblique fissure separates the inferior from the middle and upper lobes. The short horizontal fissure separates the superior and middle lobes.

Question 36

A 28 year old man is shot in the right chest and develops a right haemothorax necessitating a thoracotomy. The surgeons decide to place a vascular clamp across the hilum of the right lung.
Which of the following structures will lie most anteriorly at this point?

Answer 36

Phrenic nerve

The phrenic nerve lies anteriorly at the root of the right lung.

Question 37

58 of 73

Which of the following structures accompanies the posterior interventricular artery within the
posterior interventricular groove?

Answer 37

Middle cardiac vein

Question 37

55 of 73

Which of the following is not contained within the middle mediastinum?

Answer 37

Thoracic duct

The thoracic duct lies within the posterior and superior mediastinum.

Question 37

56 of 73

Which nerve directly innervates the sinoatrial node?

Answer 37

Superior cardiac nerve
Right vagus nerve
Left vagus nerve
inferior cardiac nerve
None of the above ( Right)

No single one of the above nerves is responsible for direct cardiac innervation (which those who have handled the heart surgically will appreciate).
The heart receives its nerves from the superficial and deep cardiac plexuses. The cardiac plexuses send small branches to the heart along the major vessels, continuing with the right and left coronary arteries. The vagal efferent fibres emerge from the brainstem in the roots of the vagus and accessory nerves, and run to ganglia in the cardiac plexuses and within the heart itself.

The background vagal discharge serves to limit heart rate, and loss of this background vagal tone accounts for the higher resting heart rate seen following cardiac transplant.

Question 38

59 of 73

Which of the following relationship descriptions regarding the scalene muscles is incorrect?

Answer 38

The subclavian artery passes posterior to the middle scalene

The subclavian artery passes anterior to the middle scalene.

Question 38

60 of 73

A 56 year old man is having a long venous line inserted via the femoral vein into the right atrium for CVP measurements. The catheter is advanced through the IVC. At which of the following levels does this vessel enter the thorax?

Answer 38

T8

The IVC passes through the diaphragm at T8.

Question 39

62 of 73

A 72 year old man with carcinoma of the lung is undergoing a left pneumonectomy. The left main bronchus is divided. Which of the following thoracic vertebrae lies posterior to this structure?

Answer 39

T6

The left main bronchus lies at T6. Topographical anatomy of the thorax is important as it helps surgeons to predict the likely structures to be injured in trauma scenarios (so popular with examiners)

Question 40

64 of 73

Which of the following most commonly arises from the brachiocephalic artery?

Answer 40

Thyroidea ima artery

Other occasional branches include the thymic and bronchial branch.

Question 41

65 of 73

A 72 year old man is undergoing a left pneumonectomy for carcinoma of the bronchus. As the surgeons approach the root of the lung, which structure will lie most anteriorly (in the anatomical plane)?

Answer 41

Phrenic nerve

The phrenic nerve is the most anteriorly located structure in the lung root. The vagus nerve lies most posteriorly.

Question 41

66 of 73

What is embryological origin of the pulmonary artery?

Answer 41

six pharengeal arch

The proximal part of the sixth right pharyngeal arch gives origin to the right pulmonary artery. The distal part gives origin to the left pulmonary artery and the ductus arteriosus.

Question 42

67 of 73

The thebesian veins contribute to the venous drainage of the heart. Into which of the following structures do they primarily drain?

Answer 42

Atrium

The thebesian veins are numerous small veins running over the surface of the heart they drain into the heart itself. Usually this is to the atrium directly.

Question 43

71 of 73

During a tricuspid valve repair the right atrium is opened, following establishment of cardiopulmonary bypass. Which of the following structures do not lie within the right atrium?

Answer 43

Trabeculae carnae

Structures within the right atrium:
- Musculi pectinati
- Crista terminalis
- Opening of the coronary sinus
- Fossa ovalis

The trabeculae carnae are located in the right ventricle.

Question 43

68 of 73

When performing minor surgery in the scalp, which of the following regions is considered a danger area as regards spread of infection into the CNS?

Answer 43

Loose areolar tissue

This area is most dangerous as infections can spread easily. The emissary veins that drain this area may allow sepsis to spread to the cranial cavity.

Question 44

69 of 73

During a gangland gunfight a man is shot in the chest. The bullet passes through the posterior mediastinum (from left to right). Which of the following structures is least likely to be injured

Answer 44

Arch of the azygos vein

The arch of the azygos vein lies in the middle mediastinum.

Question 44

70 of 73

A 63 year old man is undergoing an upper GI endoscopy for dysphagia. At 33 cm (from the incisors) a malignant looking stricture is encountered. The endoscopist attempts a balloon dilatation. Unfortunately the tumour splits through the oesophageal wall. Into which region will the oesophageal contents now drain?

Answer 44

Posterior mediastinum

At this position the oesophagus is still likely to be intrathoracic and located in the posterior mediastinum.

Question 45

72 of 73

A 63 year old man is undergoing a right pneumonectomy for carcinoma of the bronchus. As the surgeons approach the root of the lung, which structure will lie most posteriorly (in the anatomical plane)?

Answer 45

Vagus nerve

The vagus nerve is the most posteriorly located structure at the lung root. The phrenic nerve lies most anteriorly.

Question 46

73 of 73

How many valves lie between the superior vena cava and the right atrium?

Answer 46

None ( Right)
One
Two
Three
Four

There are no valves which is why it is relatively easy to insert a CVP line from the internal jugular vein into the right atrium.