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.