4- Thorax MSQs Only (2) Flashcards
1- 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)?
Vagus nerve
The vagus nerve is the most posteriorly located structure at the lung root. The phrenic nerve lies
most anteriorly.
3- How many valves lie between the superior vena cava and the right atrium?
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.
2- 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?
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.
4- 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?
Posterior mediastinum
At this position the oesophagus is still likely to be intrathoracic and located in the posterior mediastinum.
5- The thebesian veins contribute to the venous drainage of the heart. Into which of the following structures do they primarily drain?
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.
6- 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
Arch of the azygos vein
The arch of the azygos vein lies in the middle mediastinum.
7- What is embryological origin of the pulmonary artery?
Sixth pharyngeal 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.
8- 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?
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)
9- Which of the following structures accompanies the posterior interventricular artery within the
posterior interventricular groove?
Middle cardiac vein
10- Which nerve directly innervates the sinoatrial node?
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.
11- Which of the following is not contained within the middle mediastinum?
Thoracic duct
The thoracic duct lies within the posterior and superior mediastinum.
12- 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?
Phrenic nerve
The phrenic nerve lies anteriorly at the root of the right lung.
13- How many fissures are present within the right lung?
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.
14- 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?
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.
15- 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?
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.
15- Which of the following overlies the outer muscular layer of the intrathoracic oesophagus?
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.
17- Which of the following types of epithelium lines the lumenal surface of the normal oesophagus?
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.
18- Which of the following is true in connection with the phrenic nerves?
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.
19- 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?
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.
20- 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?
Mitral valve replacement with metallic valve
21- Which structure is least likely to be found at the level of the sternal angle?
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 include the left brachiocephalic vein.
22- 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?
T5
The trachea bifurcates at the level of the fifth thoracic vertebra. Or the sixth in tall subjects.
23- Which of the following pairings are incorrect?
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.
24- An 18 year old lady with troublesome hyperhidrosis of the hands and arms is due to undergo a sympathectomy to treat the condition. Which of the following should the surgeons divide to most effectively treat her condition?
Sympathetic ganglia at T2 and T3
To treat hyperhidrosis the sympathetic ganglia at T2 and T3 should be divided. Dividing the other structures listed would either carry a risk of Horners syndrome or be ineffective.
26- The right and left pulmonary arteries are derived from which of the following embryological aortic arches?
Sixth
Pulmonary vessels develop from the sixth arch
25- A 53 year old man with a carcinoma of the lower third of the oesophagus is undergoing an oesophagogastrectomy. As the surgeons mobilise the mid part of the oesophagus, where are they most likely to encounter the thoracic duct?
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 exits the thorax at T12 together with the aorta.
28- A patient has a chest drain insertion. There is fresh blood at the chest drain insertion area. Which vessel has been damaged?
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.
27- 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)?
Phrenic nerve
The phrenic nerve is the most anteriorly located structure in the lung root. The vagus nerve lies most
posteriorly.
29- Which of the following are not generally supplied by the right coronary artery?
The circumflex artery
The circumflex artery is generally a branch of the left coronary artery.
30- During an Ivor Lewis Oesophagectomy for carcinoma of the lower third of the oesophagus which structure is divided to allow mobilisation of the oesophagus?
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.
31- 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 to have originated?
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.
32- What are the boundaries of the ‘safe triangle’ for chest drain insertion?
Bounded by latissimus dorsi, pectoralis major, line superior to the nipple and apex at the axilla
A 63 year old man is undergoing a coronary artery bypass procedure. During the median sternotomy which structure would routinely require division?
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, iatrogenic injury to this structure will result in considerable haemorrhage.
34- Which of the following statements relating to the right phrenic nerve is false?
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
The right phrenic nerve passes over the right atrium
35- Where is the centre of the ‘safe triangle’ for chest drain insertion located?
5th intercostal space, mid axillary line
‘Safe Triangle’ for chest drain insertion:
5th intercostal space, mid axillary
36- 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?
Serosa
The oesophageal wall lacks the serosa layer
The wall lacks a serosa which can make the wall hold sutures less securely.
37- 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?
Parietal pleura
The sympathetic chain lies posterior to the parietal pleura. During a thorascopic sympathectomy this structure will need to be divided. The intercostal vessels lie posteriorly. They may be damaged with troublesome bleeding but otherwise are best left alone as deliberate division will not improve surgical access
38- Inspection of the left ventricle reveals all except which of the following?
Conus arteriosus
The conus arteriosus (infundibulum) is the smooth walled outflow tract of the right ventricle leading to the pulmonary trunk.
39- 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?
Aortic arch
Mneumoic for lower sternal angle:
Red, white, blue and air 2
Aortic orifice of diaphragm red- arch of aorta
white- the thoracic duct crosses at the midline
blue- azygous joins the svc
air- tracheal bifurcation
2- costal cartilage of the second rib
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.
40- Which of the structures listed below are not located within the mediastinum?
Vertebral bodies
The vertebral bodies lie outside of the mediastinum, as do the lungs.
41- 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?
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.
42- 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 ( Right)
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.
43- Where are the greatest proportion of musculi pectinati found?
Right atrium
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.
44- During a neck dissection, a nerve is noted to pass posterior to the medial aspect of the first rib. Which of the nerves listed below is this most likely to be?
Phrenic nerve
The key point is that the phrenic nerve runs posterior to the medial aspect of the first rib. Superiorly, it lies on the surface of scalenus anterior.
45- A patient presents with superior vena caval obstruction. How many collateral circulations exist as alternative pathways of venous return?
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.
46- Which of the structures listed below accompanies the aorta as it traverses the aortic hiatus?
Thoracic duct
The aorta is accompanied by the thoracic duct as it traverses the aortic hiatus. The vagal trunks accompany the oesophagus which passes through the muscular part of the diaphragm on the right. The right phrenic nerve accompanies the IVC as it passes through the caval opening. The left phrenic nerve passes through the muscular part of the diaphragm anterior to the central tendon on the left.
47- 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?
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.
48- Which of the following fascial structures encases the apex of the lungs?
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.
