Thorax Flashcards
Which is true regarding the pleural reflections
A The sternal line of pleural reflection on the right side deviates at the level of the 6th coastal cartilage, but on the left at the 4th costal cartilage
B The right and left side pleural reflections are symmetrical
C The reflection lines are lines along which the visceral pleural changes direction as it passes form one wall of the pleural cavity to another
D There are 3 pleural reflection lines: sternal, costal and mediastinal
A
Explanation
Pleural reflections (sternal, costal and vertebral) are abrupt lines along which the parietal pleura changes direction as it passes (reflects) from one wall of the pleural cavity to the other. Three pleural reflection lines outline the extent of the pleural cavity on each side: sternal, costal and diaphragmatic. The outlines of the right and left pulmonary cavities are asymmetrical (not mirror images) because of the heart on the left side imposing on the cavity. Deviation of the heart to the left side primarily affects the right and left sternal lines of pleural reflection. The sternal line of pleural reflection on the right side deviates at the level of the 6th costal cartilage, but on the left at the 4th costal cartilage.
Extra:
The parietal pleural outlines are important to know for both viva and written. Start 3cm above clavicle in MCL, come together at 2nd Rib sternal edge. Diverge at 4th sternal edge left, 6th right. Mid clavicular line level 8th rib. Mid axillary line level 10th rib. Come together at T12, 12th rib in midline. Note lung parenchyma typically 2 rib spaces higher than parietal pleura boundary.
surface anatomy:
MCL: lung 6 / parietal pleura 8
MAL: lung 8 / parietal pleura 8
scapular line: lung 10/ parietal pleura 12
fissures:
- oblique: T2 –> 6th costal cartilage (medial border of scapula when abducted)
- horizontal: 4th rib & costal cartilage from oblique fissure
Which is true regarding the right vagus and phrenic nerves and their relations in the superior mediastinum?
A Right phrenic nerve passes along the left side of the right brachiocepahlic vein, SVC and the pericardium over the right atrium
B Right phrenic nerve enters the superior mediastinum between the brachiocephalic trunk and the origin of the brachiocepahlic vein
C Right vagus nerve passes through the superior mediastinum to the right of the trachea, posterior to the right brachiocephalic vein, SVC and root of the right lung
D Right vagus nerve enter the superior mediastinum posterior to the sternoclavicular joint and common carotid artery
Right Phrenic Nerve
C
Explanation
The vagus nerves exit the cranium & descend through the neck posterolateral to the CCA. Enter the superior mediastinum posterior to their respective sternoclavicular joints and brachiocephalic veins.
The right vagus nerve (RVN) enters the thorax anterior to the R subclavian artery, giving rise to the right recurrent laryngeal nerve. The RCLN hooks around the right subclavian artery & ascends between the trachea & oesophagus to supply the larynx. The RVN then runs posteroinferiorly through the superior mediastinum on the right side of the trachea. It then passes posterior to the right brachiocephalic vein, SVC and root of the right lung. Here it divides into many branches contributing to the right pulmonary plexus. The RVN usually leave the right pulmonary plexus as a single nerve and passes to the oesophagus where it splits up again to contribute to the oesophageal plexus. RVN also contributes to the cardiac plexus.
Left vagus nerve descends in the neck posterior to the left CCA. It enters the superior mediastinum between the left CCA and left subclavian arteries. When the LVN reaches the left side of the arch of aorta, it diverges posteriorly from the left phrenic nerve. The LVN is separated laterally from the phrenic nerve by the left superior intercostal vein. As LVN curves medially at the inf border of arch of aorta, it gives off the left recurrent laryngeal nerve. The LVN passes posterior to the root of left lung where it breaks up into many branches that contribute to the left pulmonary plexus. The LVN leaves this plexus as a single trunk and passes to the esophagus where it joins fibers from right vagus in the esophageal (nerve) plexus.
- supply the diaphragm with motor & sensory fibres
- supply sensory fibres to the pericardium & mediastinal pleura
Each phrenic nerve enters the superior mediastinum between the subclavian artery and the origin of brachiocephalic vein. Passes anterior to the roots of lung.
The right phrenic nerve passes along the right side of the right brachiocepahlic vein, SVC and the pericardium over the right atrium. It also passes anterior to the root of the right lung and descends on the right side of the IVC to the diaphragm, which it pierces near the caval opening.
The left phrenic nerve enters the superior mediastinum between the left subclavian artery and left CCA. It crosses the left surface of the arch of aorta anterior to the left vagus nerve and passes over the left superior intercostal vein. The LPN then descends anterior to the root of the left lung and runs along the fibrous pericardium, superficial to the LA and ventricles of the heart, where it pierces the diaphragm to the left of pericardium. Most branching of the phrenic nerves for distribution to the diaphragm occurs on the diaphragm’s inferior (abdominal) surface.
Regarding the right coronary artery which of the following statements is correct?
A The RCA arises form the right aortic sinus
B Its course is through the left auricle and infundibulum
C Supplies 30% of sino-atrial (SA) nodes
D Supplies 60% of atrio-ventricular (AV) nodes
A
Explanation
Courses through the right ventricle; supplies the sino-atrial (SA) node in 60% of people and the AV node in 80% of people. It supplies most of the right atrium, most of the right ventricle, part of the left ventricle (the diaphragmatic surface), part of the IV septum, usually the posterior third.
Note: RCA arises from the anterior aortic sinus, newer sources (current text book) say the right aortic sinus of the ascending aorta. The LCA arises from the left aortic sinus of the ascending aorta. No artery arises from the posterior aortic (non-coronary) sinus
LCA supplies the left atrium, most of the LV, part of the RV, most of the IVS (anterior 2/3) including the AV bundle of the conducting system of the heart, through its perforating IV septal branches. SA node in approximately 40% of people
Regarding the phrenic nerve, which of the following statements is correct?
A They give of a recurrent laryngeal nerve branch
B Structures relating to both phrenic nerves are identical
C They arise principally from C5 nerve root
D Each phrenic nerve supplies only one side of the diaphragm
D
Explanation
Right phrenic nerve is medially related to venous structures whereas the left phrenic nerve is related to arterial structures; arise principally from C4-but remember that the total origin is C3-C5; the recurrent laryngeal branch is a branch of the vagus nerve
Extra:
Memory aid: C3, 4, 5 keeps the diaphragm alive.
Regarding the Internal thoracic artery, which of the following statements is correct?
A The internal thoracic artery is crossed near their origins by the ipsilateral phrenic nerve
B It descends straight down 1 cm medially to border of sternum
C Gives off two anterior intercostal branches to the 5 superior intercostal spaces
D It is a branch of 2nd part of subclavian artery
A
Explanation
Arises in the root of the neck, descends into the thorax posterior to the clavicle and first costal cartilage. It descends 1 cm lateral to the border of the sternum. It is a branch of the first part of the subclavian and gives off 2 anterior intercostal arteries in each intercostal space. It directly supplies the superior 6 intercostal spaces. Therefore the total number of branches is 12.
Which of the following statements is correct regarding the oesophagus?
A Is 28cm long
B Is narrowest at the commencement at the cricopharyngeal sphincter
C Ends at the cardiac orifice of the stomach at level T10
D Begins at the lower border of the thyroid cartilage
B
Explanation
The esophagus, a muscular tube, 25 cm long begins at the lower border of the cricoid cartilage at C6, passes through the diaphragm at the level of T10 and ends at the cardiac orifice at the level of T11 which is the cardiac orifice. Is narrowest at the commencement at the cricopharyngeal sphincter (upper esophageal sphincter). Other sites of constriction include thoracic constriction: where it is crossed by the aortic arch and then by the left main bronchus. Diaphragmatic constriction: where it passes through the esophageal hiatus of the diaphragm.
Extra:
The anatomical relations of the oesophagus give rise to four physiological constrictions in its lumen – is these areas where food/foreign objects are most likely to become stuck. They can be remembered using the acronym ‘ABCD‘: Arch of aorta, Bronchus (left main stem), Cricoid cartilage, Diaphragmatic hiatus
COA:
The esophagus is a fibromuscular tube that extends from the pharynx to the stomach. The esophagus enters the superior mediastinum between the trachea & vertebral column, where it lies anterior to the bodies of T1-4 vertebrae. The esophagus is usually flattened anteroposteriorly. Initially, it inclines to the left but is pushed back to the median plane by the arch of aorta. It is then compressed anteriorly by the root of the left lung. In the superior mediastinum, the thoracic duct usually lies on the left side of the esophagus, deep (medial) to the arch of aorta. Inferior to the arch, the esophagus again inclines to the left as it approaches and passes through the esophageal hiatus in the diaphragm.
Which is true in respect of the anatomy of the trachea?
A In the first year of life the trachea is 5mm in diameter
B It is 20cm long and bifurcates below the manubrium sterni
C It has a 3.5cm diameter in adults
D It starts at the level of the cricoid cartilage which is below C6
D
Explanation
Trachea is 10cm long and 2.5cm in diameter. In the first year of life it is roughly the diameter of a pencil according to the textbook
A web search says that a pencil’s diameter is roughly 6mm.
A web search of an infant’s trachea gives 4mm as an answer.
Not a great question, but I have left the stems as is.
COA:
The trachea descends anterior to the esophagus and enters the superior mediastinum, inclining a little to the right of the median plane. The posterior surface of the trachea is flat where it is applied to the esophagus. The trachea ends at the level of the sternal angle (T4/5) by dividing into right and left main bronchi. The trachea terminates superior to the level of the heart & is not a component of the posterior mediastinum.
Regarding the coronary arteries, which of the following statements is correct?
A The circumflex is the artery most affected by disease
B The right coronary artery has a posterior interventricular branch
C 40% of sino-atrial (SA) nodes are supplied by the right coronary artery
D 50% of atrio-ventricular (AV) nodes are supplied by the right coronary artery
B
Explanation
80% of atrio-ventricular (AV) nodes are supplied by the right coronary artery (RCA), 60% of sino-atrial (SA) nodes are also supplied by the RCA. The anterior interventricular artery is most affected by disease
With regard to the bronchopulmonary segments, all of the following statements are true except?
A The superficial bronchial veins of the right main bronchus drain into the azygos vein
B There are approximately 9 segments in each lung
C Material aspirated tends to lodge in apical segment of the right lower lobe
D The lingular portion of the superior left lobe is divided into an upper and lower segment
B
Explanation
There are 10 bronchopulmonary segments in each lung. Aspirated material by supine, comatose or anaesthetised patients tends to lodge in apical segment of the right lower lobe as patients. The bronchial veins fall into a superficial system draining from the hilar region and visceral pleura in to the azygos vein on the right and the accessory hemiazygos vein on the left. The deep system from the deeper lung tissue drain to a main pulmonary vein or directly into the left atrium
Note: clinical Moore says there may be 8 segments in the left lung depending on the combintation of segments. If you group the apical and posterior segments=apicoposterior and the anterior and medial basal segments=anteriomedial, you get eight.
Lasts calls the lingular portions-superior and inferior segments. CM says superior and inferior portions
Which of the following is a correct relationship as regards the chest wall?
A The intercostal artery is more superficial than the vein
B The neurovascular bundle lies between the external and internal intercostals
C The intercostal artery lies between the nerve and vein
D The transversus muscle lies between the internal and external intercostals
C
Explanation
The neurovascular bundle lies between the internal intercostal and innermost intercostal muscles. The transverse muscle lies below the internal intercostal muscles. The intercostal artery is not more superficial than the vein
Layers:
Skin –> subcutaneous tissues –> external intercostal muscle –> internal intercostal muscle –> intercostal space (vein, artery, nerve) –> innermost intercostal muscle –> transversus thoracis muscle
Which of the following levels is correct in relation to the oesophageal opening in the diaphragm?
A T12
B T6
C T10
D T8
C
Explanation
T8 - Vena cava foramen
- accompanied by right phrenic nerve
T10 - Oesophagus
- accompanied by vagus nerve
T12 - Aortic opening
- accompanied by thoracic duct & azygos vein
Nice way to remember:
T8 - vena cava (8 letters)
T10 - oesophagus (10 letters) T12 - aortic hiatus (12 letters)
and even: I ate 10 eggs at 12. (I=IVC, ate=8, Eggs=Eosophagus, At=Aorta)
Which of the following statements is true in relation to the trachea?
A Drains into the axillary lymph nodes
B Enters the thoracic inlet slightly to the left of midline
C Is supplied by glossopharyngeal nerve
D Its lower end is behind the manubrium
D
Explanation
The trachea commences at C6 level, 5cm above the jugular notch. It enters the thoracic inlet in the midline and passes downwards and backwards behind the manubrium to bifuricate into the two main bronchi. The trachea is 10cm long and 2cm wide, It drains into the posterior group of deep cervical and paratracheal lymph nodes. It is innervated by afferent fibres from vagi and recurrent laryngeal nerves
Note: The current textbook writes that the trachea ends at the level of the sternal angle by dividing into left and right main bronchi.The sternal angle is the join between the manubrium and the body of the sternum
Which of the following is the most anterior structure in the thoracic inlet?
A Thoracic duct
B Vagus nerve
C Right subclavian artery
D Subclavian vein
D
Explanation
Think of the edge of the right axilla on top of the 1st rib: vein anteriorly (thus approach for subclavian CVCs), scalenus anterior (which the phrenic nerve runs over), followed by the subclavian artery (which the right vagus runs over medially, then give off the recurrent laryngeal branch under and behind the subclavian artery).
Which of the following statements is correct in relation to the diaphragm and its openings?
A Has an aortic opening opposite T12
B Has the oesophageal opening opposite the T8 vertebrae
C Has a vena caval opening at T10
D Is supplied by C4, 5, 6
A
Explanation
The diaphragm’s motor supply is solely from the phrenic nerves, supplied by C3, 4, 5 (but mostly C4).
“C3, 4, 5 keeps the diaphragm alive”
Openings:
T8 = venae cava opening: transmits the inferior vena cava and the right phrenic nerve
T10 = oesophageal opening: transmits the oesophagus accompanied by the vagal trunks, oesophageal branches of the left gastric artery, veins and lymphatic.
T12 = aortic opening: transmits the aorta with the azygos vein to the right and the thoracic duct leading up from the cistern chyli between them
Which structure passes through the diaphragm with the oesophagus?
A Phrenic nerve
B Azygous vein
C Thoracic duct
D Vagal trunk
D
Explanation
The vagal trunks and the oesophageal branches of the left gastric artery, veins and lymphatics accompany the oesophagus as it passes through the diaphragm
With regard to the coronary arteries, which of the following statements is correct?
A There are no arteriolar anastomoses between left and right
B Right coronary artery (RCA) arises from the posterior coronary sinus
C Right coronary artery (RCA) supplies the SA node in 60% of patients
D Left coronary artery (LCA) supplies the AV node in 80% of patients
C
Explanation
The RCA arises from the anterior aortic sinus and the LCA from the left posterior aortic sinus.
Note: The above statement is from lasts anatomy. In CM it simple states that RCA arises from the right aortic sinus and the LCA form the left aortic sinus
The RCA supplies the sino-atrial (SA) node in 60% of patients and the AV node in the majority (80%) of patients (via the nodal artery form the posterior descending artery). The posterior descending artery (the posterior interventricular branch) is supplied by the RCA. Anastomoses exist at the termination of the right and left coronary arteries in the atrioventricular groove and between their interventricular and conus branches
Which of the following muscles is not used in forced expiration?
A internal oblique muscles
B rectus abdominis
C external oblique muscles
D diaphragm
D
Explanation
The major role of the diaphragm is inspiration, but it is also involved in abdominal straining. The external intercostals are the most active in inspiration and the internal intercostals in expiration
Whether expiration is quiet or forced (coughing, sneezing, blowing) the diaphragm is wholly passive, its relaxed fibres being elongated by pressure from below. The most important muscles of forced expiration include those of the abdominal wall-rectus abdominis, internal and external oblique muscles and the transverse abdominis muscle.
Note: the intercostal muscles are used for inspiration but paralysis of the intercostal muscles alone does not seriously affect breathing because the diaphragm is so effective. The anatomy TB states: main action of external intercostals is forced inspiration
Which structure passes directly behind the hilum of the right lung?
A Hemi-azygous vein
B Right phrenic nerve
C Internal mammary artery
D Right vagus nerve
D
Explanation
Both Vagus nerves run behind the lung root (closer to the Vertebrae). Both Phrenic nerves run in-front of the lung root (closer to the Pericardium). Internal Mammary/Thoracic arteries run on the internal aspect of the thoracic wall. The hemi-azygous vein is a posterior mediastinal structure, further behind the lung root than the vagus nerve.
Which is the correct layout of structures form anterior to posterior in the superior mediastinum?
A Lymphoid system, blood vascular, respiratory system, alimentary system, lymph vascular system
B Lymphoid system, respiratory system, blood vascular, lymph vascular system, alimentary system
C Lymphoid system, respiratory system, blood vascular, alimentary system, lymph vascular system
D Lymphoid system, blood vascular, respiratory system, alimentary system, nervous system
A
Explanation
Within the superior mediastinum, structures occur in systemic layers form anterior to posterior.
1: Lymphoid system-thymus
2: Blood vascular system-veins then arteries
3: Respiratory system-trachea
4: Alimentary system-oesophagus
5: Lymph vascular system-thoracic duct, bronchomediastinal trunks, posterior mediastinal lymph nodes.
Useful mnemonic: LaBeTalOL - LBTOL, anterior –> posterior structures = lymphatics (thymus), blood vessels, trachea, oesophagus, lymphatics.
Thre nervous system does not have its own layer, rather it is integrated into layer 2 (phrenic and vagus) and between layers 3 and 4 (recurrent laryngeal nerves)
The motor supply to the diaphragm is by the follwing nerve
A Subcostal nerves
B Vagus nerve
C Intercostal nerves
D Phrenic nerve
D
Explanation
Diaphragm innervation
Motor supply: phrenic nerves (C3-C5)
Sensory supply: centrally by the phrenic nerves, peripherally by the intercostal nerves (T5-T11) and the subcostal nerves (T12)
Which part of the heart does the right coronary artery NOT SUPPLY?
A The posterior inferior surface of the left ventricle
B Most of the right ventricle
C Usually the posterior third of the interventricular septum
D The right atrium
A
Explanation
The RCA typically supplies the following:
The right atrium
Most of the right ventricle
The diaphragmatic surface of the left ventricle
Usually the posterior third of the interventricular septum
The SA node (60%)
AV node (80%)
Which is true regarding the aortic arch and its relations?
A The bifurcation of the pulmonary artery and the right main bronchus are found at the level of the arch
B The aortic arch becomes the descending aorta at the level of T4
C The trachea lies behind and to the left of the aortic arch.
D Ligamentum venosum connects the left pulmonary artery to the aortic arch
B
Explanation
The arch of the aorta begins at the level of the upper border of the second sternocostal articulation of the right side, and runs at first upward, backward, and to the left in front of the trachea; it is then directed backward on the left side of the trachea and finally passes downward on the left side of the body of the fourth thoracic vertebra, at the lower border of which it becomes continuous with the descending aorta (posterior to the 2nd intercostal joint). It thus forms two curvatures: one with its convexity upward, the other with its convexity forward and to the left. Its upper border is usually about 2.5 cm. below the superior border to the manubrium sterni.
Relations.—The arch of the aorta is covered anteriorly by the pleurae and anterior margins of the lungs, and by the remains of the thymus. As the vessel runs backward its left side is in contact with the left lung and pleura. Passing downward on the left side of this part of the arch are four nerves; in order from before backward these are, the left phrenic, the lower of the superior cardiac branches of the left vagus, the superior cardiac branch of the left sympathetic, and the trunk of the left vagus. As the last nerve crosses the arch it gives off its recurrent branch, which hooks around below the vessel and then passes upward on its right side. The highest left intercostal vein runs obliquely upward and forward on the left side of the arch, between the phrenic and vagus nerves. On the right are the deep part of the cardiac plexus, the left recurrent nerve, the oesophagus, and the thoracic duct; the trachea lies behind and to the right of the vessel. Above are the innominate, left common carotid, and left subclavian arteries, which arise from the convexity of the arch and are crossed close to their origins by the left innominate vein. Below are the bifurcation of the pulmonary artery, the left bronchus, the ligamentum arteriosum, the superficial part of the cardiac plexus, and the left recurrent nerve. The ligamentum arteriosum connects the commencement of the left pulmonary artery to the aortic arch.
Note: The bifurcation of the pulmonary artery occurs under the concavity of the arch and the right main bronchus begins at the upper border of T5
Which of the following statements regarding the mitral valve is CORRECT?
A The anterior cusp is weaker than the posterior cusp
B The mitral valve has two cusps, anterior and posterior
C The cusps receives tendinous cords from only one papillary muscle
D The mitral valve is located posterior to the sternum at the level of the 3rd costal cartilage
B
Explanation
The double leaflet mitral valve guards the left atrioventricular orifice. The mitral valve has two cusps, anterior and posterior. The anterior cusp is thicker and more rigid than the posterior cusp. The anterior cusp lies between the mitral and aortic orifices and thus lies between the inflow and outflow tracts of the left ventricle. The mitral valve is located posterior to the sternum at the level of the 4th costal cartilage. Each of its cusps receives tendinous cords from more than one papillary muscle.
At what costal level does the pleura reflection reach at the mid axillary line
A 10th rib
B 8th rib
C 12th rib
D 6th rib
A
Explanation
Pleural reflections:
Anterior median line= 6th costal cartilage on the right and 4th of the left
Mid clavicular line= 8th rib (lower lung border 6th)
Mid axillary line= 10th rib (lower lung border 8th)
Mid scapular line= 12th rib (lower lung border 10th)
The mitral valve is located posterior to which costal cartilage?
A 5th costal cartilage
B 2nd costal cartilage
C 4th costal cartilage
D 3rd costal cartilage
C
Explanation
The mitral valve has two cusps, anterior and posterior. It is located posterior to the sternum at the level of the 4th costal cartilage.
At the level of which intercostal cartilage does the superior vena cava (SVC) drain into the right atrium?
A 5th intercostal cartilage
B 2nd intercostal cartilage
C 4th intercostal cartilage
D 3rd costal cartilage
D
Explanation
The superior vena cava returns blood from all structures superior to the diaphragm, except the lungs and heart. It passes inferiorly and ends at the level of the 3rd costal cartilage, where is enters the right atrium o the heart.
The internal thoracic artery is a branch of which of the following?
A Vertebral artery
B Axillary artery
C Thyrocervical trunk
D Subclavian artery
D
Explanation
The subclavian artery is divided into three parts relative to the anterior scalene muscle.
The first part runs from the origin of the subclavian artery to the medial border of the anterior scalene muscle. Its branches include the vertebral artery, internal thoracic artery, and thyrocervical trunk.
The second part runs posterior to the anterior scalene muscle. It gives off the costocervical trunk.
The third part runs from the lateral border of the anterior scalene muscle to the lateral border of the first rib. It gives off the dorsal scapular artery. At the lateral border of the first rib, the subclavian artery enters the axilla and becomes the axillary artery.
Anterior relations of the internal thoracic artery include
A Axillary artery
B Upper six intercostal spaces
C Posterior root of the lung
D Sternum
B
Explanation
The internal thoracic artery arises in the root of the neck from the inferior surface of the first part of the subclavian artery. It descends into the thorax posterior to the clavicle and 1st costal cartilage. It is crossed near its origin by the ipsilateral phrenic nerve. It descends on the internal surface of the thorax slightly lateral to the sternum and posterior to the upper six costal cartilages. It terminates in the 6th intercostal space, dividing into superior epigastric and musculophrenic arteries. It directly gives rise to anterior intercostal arteries supplying the superior six intercostal spaces.
The intercostals increase the volume of the thorax in which dimension?
A Anterior-posterior
B Oblique
C Vertical
D Lateral
A
Explanation
The anterior-posterior dimension of the thorax increases considerably when the intercostal muscles contract. Movement of the ribs (primarily 2nd-6th) at the costovertebral joints around an axis passing through the necks of the ribs causes the anterior ends of the ribs to rise- the pump handle movement. Because the ribs slope inferiorly, their elevation also results in anterior -posterior movement of the sternum, especially its inferior end, with slight movement occurring at the manubriosternal joint in young people.
Knowledge of the axilla is important in the emergency department for insertion of chest drains. The costal line of pleural reflection crosses the mid-axillary line at which rib?
A 12th
B 6th
C 10th
D 8th
C
Explanation
The lines of pleural reflection cross the mid-clavicular line at the 8th rib, MAL at 10th rib, and mid-scapular line at the 12th rib.
The right costal line of pleural reflection begins at the mid-clavicular line. Which rib does this correspond to?
A 8th
B 6th
C 12th
D 10th
A
Explanation
The lines of pleural reflection cross the mid-clavicular line at the 8th rib, midaxillary line at 10th rib, and mid-scapular line at the 12th rib.
A 60-year-old lady presents with a cough and fever. Her CXR reveals consolidation in the posteroinferior portion of her right lower lobe. Percussion adjacent to which vertebral level would reveal an abnormality?
A T8
B T2
C T6
D T4
A
Explanation
The posteroinferior portion of the right lower lobe is the most inferior segment of the right lower lobe. The lungs and visceral pleura run parasternal to the 6th costal cartilage on the right, and 4 th costal cartilage on the left, then pass laterally to the mid-clavicular at the 6th rib level, midaxillary line at the 8th rib level, and the mid-scapular line at the 10th rib level. Percussion just above the 10th rib level, adjacent to T8-9 is most likely to reveal her abnormality.
Which is primarily responsible for the peripheral sensory supply to the diaphragm?
A Subcostal nerves
B Phrenic nerve
C Vagus nerve
D Intercostal nerves
D
Explanation
Sensory supply to the diaphragm is mostly from the phrenic nerves. Peripheral parts of the diaphragm receive their sensory supply from intercostal nerves (lower six or seven) and the subcostal nerves.
A 45-year-old man suffers an acute myocardial infarction and is brought to your emergency department for acute management.
He develops a left ventricular wall thrombus with motion artefact. This is most likely due to occlusion of which vessel?
A Right coronary artery
B Left main coronary artery
C Left circumflex artery
D Left anterior descending artery
D
Explanation
Left ventricular wall thrombus most commonly occurs in anterior wall MI, supplied by the left anterior descending artery
A patient is stabbed in the anterior chest to the left of the sternum. Which structure is most likely damaged?
A Left atrium
B Right ventricle
C Right atrium
D Left ventricle
B
Explanation
The anterior (sternocostal) surface of the heart equates to the RV. Other surfaces include: Diaphragmatic (inferior) surface - LV and part of RV Right pulmonary surface - right atrium Left pulmonary surface - LV
What, either directly or indirectly, provide sensation to the majority of the peripheral diaphragmatic pleura?
A Subcostal nerves
B Intercostal nerves
C Costophrenic nerves
D Phrenic nerves
B
Explanation
Sensory innervation (pain and proprioception) to the central diaphragm is also mostly from the phrenic nerves. Peripheral parts of the diaphragm receive their sensory nerve supply from the intercostal nerves (T5-T11) and the subcostal nerves (T12).
The entire motor supply to the diaphragm is form the right and left phrenic nerves, each of which airises form the anterior rami C3-C5 segments of the spinal cord and is distributed to the ipsilateral half of the diaphragm form its inferior surface
What is the narrowest point of the oesophagus?
A Oesophageal cardiac constriction
B Pharyngo-oesophageal junction
C Oesophageal hiatus of the diaphragm
D Broncho-aortic constriction
B
Explanation
As seen during fluoroscopy (x-ray, using a fluoroscope) after a barium swallow, the oesophagus normally has three constrictions where adjacent structures produce impressions: (1) Cervical constriction (upper oesophageal sphincter) at its beginning at the pharyngo-oesophageal junction, (2) Thoracic (broncho-aortic) constriction a compound constriction where it is first crossed by the arch of the aorta and then the left main bronchus, (3) Diaphragmatic constriction where it passes through the oesophageal hiatus of the diaphragm
Extra:
Three areas of normal anatomic narrowing in the esophagus are commonly seen during esophagoscopy or contrast esophagogram. The superiormost narrowing is caused by the cricopharyngeus muscle at the anatomic border of the pharynx and proximal esophagus. This narrowest point of the esophagus with an average luminal diameter of 1.5 cm is the most common site of iatrogenic perforation. The crossing of the left mainstem bronchus and the aortic arch results in indentation of the anterior and left lateral esophageal wall, causing the second narrowing of the esophagus, with an average luminal diameter of 1.6 cm. The most inferior narrowing of the esophagus is at the diaphragmatic hiatus and is caused by the physiologic lower esophageal sphincter. There is great variation of the luminal diameter at this point, depending upon the normal distention of the esophagus by the passage of a food bolus, with measurements ranging from 1.6 to 2.5 cm.
source: thoracic key
Where does the right bronchial artery generally arise from?
A Right 4th posterior intercostal artery
B Right 3rd posterior intercostal artery
C Right 2nd posterior intercostal artery
D Right 1st posterior intercostal artery
B
Explanation
The two left bronchial arteries usually arise directly from the thoracic aorta.
The single right bronchial artery may also arise directly from the aorta; however, it commonly arises indirectly, either by way of the proximal part of one of the upper posterior intercostal arteries (usually the right 3rd posterior intercostal artery) or from a common trunk with the left superior bronchial artery.
