Brs Questions - Thorax

Front 1

1. A 32-year-old patient who weighed 275 pounds came to doctor's office. On the surface of the chest, a physician was able to locate the apex of the heart:
(A) At the level of the sternal angle
(B) In the left fourth intercostal space
(C) In the left fifth intercostal space
(D) In the right fifth intercostal space
(E) At the level of the xiphoid process of the
sternum
(D) Dorsal root ganglion and lateral horn of
the spinal cord
(E) Anterior and lateral horns of the spinal cord

Back 1

1. The answer is C. On the surface of the chest, the apex of the heart can be located in the left
fifth intercostal space slightly medial to the midclavicular (or nipple) line. The sternal angle is lo-
cated at the level where the second ribs articulate with the sternum. The xiphoid process lies at
the level of T10 vertebra.

Front 2

2. A 43-year-old female patient has been ly-
ing down on the hospital bed for more than 4
months. Her normal, quiet expiration is
achieved by contraction of which of the fol-
lowing structures?
(A) Elastic tissue in the lungs and thoracic wall
(B) Serratus posterior superior muscles
(C) Pectoralis minor muscles
(D) Serratus anterior muscles
(E) Diaphragm

Back 2

2. The answer is A. Normal, quiet expiration is achieved by contraction of extensible tissue in
the lungs and the thoracic wall. The serratus posterior superior muscles, diaphragm, pectoralis
major, and serratus anterior are muscles of inspiration.

Front 3

3. A 23-year-old man received a gunshot
wound and his greater splanchnic nerve was
destroyed. Which of the following nerve fibers
would be injured?
(A) General somatic afferent (GSA) and pre-
ganglionic sympathetic fibers
(B) General visceral afferent (GVA) and post-
ganglionic sympathetic fibers
(C) GVA and preganglionic sympathetic fibers
(D) General somatic efferent (GSE) and post-
ganglionic sympathetic fibers
(E) GVA and GSE fibers

Back 3

3. The answer is C. The greater splanchnic nerves contain general visceral afferent (GVA) and
preganglionic sympathetic general visceral efferent (GVE) fibers.

Front 4

4. A 17-year-old boy was involved in gang
fighting and a stab wound severed the white
rami communicantes at the level of his sixth
thoracic vertebra. This injury would_result in
degeneration of nerve cell bodies in which of
the following structures?
(A) Dorsal root ganglion and anterior horn of
the spinal cord
(B) Sympathetic chain ganglion and dorsal
root ganglion
(C) Sympathetic chain ganglion and posterior
horn of the spinal cord
(D) Dorsal root ganglion and lateral horn of
the spinal cord
(E) Anterior and lateral horns of the spinal cord

Back 4

4. The answer is D. The white rami communicantes contain preganglionic sympathetic general vis-
ceral efferent (GVE) fibers and general visceral afferent (GVA) fibers whose cell bodies are located in
the lateral horn of the spinal cord and the dorsal root ganglia. The sympathetic chain ganglion con-
tains cell bodies of the postganglionic sympathetic nerve fibers. Anterior horn of the spinal cord con-
tains cell bodies of the GSE fibers. The dorsal root ganglion contains cell bodies of GSA and GVA fibers.

Front 5

5. A 27-year-old cardiac patient with an irreg-
ular heartbeat visited her doctor's office for ex-
amination. Where should the physician place
the stethoscope to listen to the sound of the
mitral valve?
(A) Over the medial end of the second left in-
tercostal space
(B) Over the medial end of the second right
intercostal space
(C) In the left fourth intercostal space at the
midclavicular line
(D) In the left fifth intercostal space at the
midclavicular line
(E) Over the right half of the lower end of
the body of the sternum

Back 5

5. The answer is D. The mitral valve (left atrioventricular [AV] valve) produces the apical beat
(thrust) of the heart, which is most audible over the left fifth intercostal space at the midclavicular
line. The pulmonary valve is most audible over the medial end of the second left intercostals space,
the aortic valve is most audible over the medial end of the second right intercostals space, and the
right AV valve is most audible over the right half of the lower end of the body of the sternum.

Front 6

6. A 19-year-old man came to the emergency
department and his angiogram exhibited that
he was bleeding from the vein that is accom-
panied by the posterior interventricular artery.
Which of the following veins is most likely to
be ruptured?
(A) Great cardiac vein
(B) Middle cardiac vein
(C) Anterior cardiac vein
(D) Small cardiac vein
(E) Oblique veins of the left atrium

Back 6

6. The answer is B. The middle cardiac vein ascends in the posterior interventricular groove, ac-
companied by the posterior interventricular branch of the right coronary artery. The great cardiac
vein is accompanied by the anterior interventricular artery, the anterior cardiac vein drains di-
rectly into the right atrium, and the small cardiac vein is accompanied by the marginal artery.

Front 7

7. A 37-year-old patient with palpitation was
examined by her physician, and one of the di-
agnostic records included a posterior-anterior
chest x-ray film. Which of the following com-
prise the largest portion of the sternocostal sur-
face of the heart seen on the radiograph?
(A) Left atrium
(B) Right atrium
(C) Left ventricle
(D) Right ventricle
(E) Base of the heart

Back 7

7. The answer is D. The right ventricle forms a large part of the sternocostal surface of the heart.
The left atrium occupies almost the entire posterior surface of the right atrium. The right atrium oc-
cupies the right aspect of the heart. The left ventricle lies at the back of the heart and bulges roundly
to the left. The base of the heart is formed by the atria, which lie mainly behind the ventricles.

Front 8

8. A 7-year-old boy has a damaged interven-
tricular septum. Which of the following valves
is most likely defective?
(A) Pulmonary valve
(B) Mitral valve
(C) Valve of coronary sinus
(D) Tricuspid valve
(E) Aortic valve

Back 8

8. The answer is D. The septal cusp of the tricuspid valve is attached by a cordae tendineae to
the septal papillary muscle, which arises from the interventricular septum. Other valves are not
associated with the interventricular (IV) septum.

Front 9

9. A 54-year-old patient is implanted with an
artificial cardiac pacemaker. Which of the fol-
lowing conductive tissues of the heart had a de-
fective function that required the pacemaker?
(A) Atrioventricular (AV) bundle
(B) AV node
(C) Sinoatrial (SA) node
(D) Purkinje fiber
(E) Moderator band

Back 9

9. The answer is C. The sinoatrial (SA) node initiates the impulse of contraction and is known
as the pacemaker of the heart. Impulses from the SA node travel through the atrial myocardium
to the atrioventricular (AV) node and then race through the AV bundle (bundle of His), which di-
vides into the right and left bundle branches. The bundle breaks up into terminal conducting
fibers (Purkinje fibers) to spread out into the ventricular walls. The moderate band carries the
right limb of the AV bundle from the septum to the sternocostal wall of the ventricle.

Front 10

10. A thoracic surgeon removed the right mid-
dle lobar (secondary) bronchus along with
lung tissue from a 57-year-old heavy smoker
with lung cancer. Which of the following bron-
chopulmonary segments must contain cancer-
ous tissues?
(A) Medial and lateral
(B) Anterior and posterior
(C) Anterior basal and medial basal
(D) Anterior basal and posterior basal
(E) Lateral basal and posterior basal

Back 10

10. The answer is A. The right middle lobar (secondary) bronchus leads to the medial and lat-
eral bronchopulmonary segments. The right superior lobar bronchus divides into the superior,
posterior, and anterior segmental (tertiary) bronchi. The right inferior lobar bronchus has the an-
terior, lateral, posterior, and anterior segmental bronchi.

Front 11

11. The bronchogram of a 45-year-old female
smoker shows the presence of a tumor in the
eparterial bronchus. Which airway is most
likely blocked?
(A) Left superior bronchus
(B) Left inferior bronchus
(C) Right superior bronchus
(D) Right middle bronchus
(E) Right inferior bronchus

Back 11

11. The answer is C. The eparterial bronchus is the right superior lobar (secondary) bronchus;
all of the other bronchi are hyparterial bronchi.

Front 12

12. An 83-year-old man with a typical coronary
circulation has been suffering from an embolism
of the circumflex branch of the left coronary ar-
tery. This condition would result in ischemia of
which of the following areas of the heart?
(A) Anterior part of the left ventricle
(B) Anterior interventricular region
(C) Posterior interventricular region
(D) Posterior part of the left ventricle
(E) Anterior part of the right ventricle

Back 12

12. The answer is D. The circumflex branch of the left coronary artery supplies the posterior por-
tion of the left ventricle. The anterior interventricular artery supplies the anterior aspects of the
right and left ventricles and the anterior interventricular septum.

Front 13

13. A 44-year-old man with a stab wound was
brought to the emergency department and a
physician found that the patient was suffering
from a laceration of his right phrenic nerve.
Which of the following conditions has likely
occurred
(A) Injury to only general somatic efferent
fibers
(B) Difficulty in expiration
(C) Loss of sensation in the pericardium and
mediastinal pleura
(D) Normal function of the diaphragm
(E) Loss of sensation in the costal part of the
diaphragm

Back 13

13. The answer is C. The phrenic nerve supplies the pericardium and mediastinal and di-
aphragmatic (central part) pleura and the diaphragm, an important muscle of inspiration. It con-
tains general somatic efferent (GSE), general somatic afferent (GSA), and general visceral efferent
(GVE) (postganglionic sympathetic) fibers. The costal part of the diaphragm receives GSA fibers
from the intercostal nerves.

Front 14

14. An 8-year-old boy with atrial septal defect
presents to a pediatrician. This congenital
heart defect shunts blood from the left atrium
to the right atrium and causes hypertrophy of
the right atrium, right ventricle, and pul-
monary trunk. Which of the following veins
opens into the hypertrophied atrium?
(A) Middle cardiac vein
(B) Small cardiac vein
(C) Oblique cardiac vein
(D) Anterior cardiac vein
(E) Right pulmonary vein

Back 14

14. The answer is D. The anterior cardiac vein drains into the right atrium. The middle, small,
and oblique cardiac veins drain into the coronary sinus. The right and left pulmonary veins drain
into the left atrium.

Front 15

15. A 37-year-old patient with severe chest
pain, shortness of breath, and congestive heart
failure was admitted to a local hospital. His
coronary angiograms reveal a thrombosis in
the circumflex branch of the left coronary ar-
tery. Which of the following conditions could
result from the blockage of blood flow in the
circumflex branch?
(A) Tricuspid valve insufficiency
(B) Mitral valve insufficiency
(C) Ischemia of atrioventricular (AV) node
(D) Paralysis of pectinate muscle
(E) Necrosis of septomarginal trabecula

Back 15

15. The answer is B. The circumflex branch of the left coronary artery supplies the left ventricle
and thus its blockage of blood flow results in necrosis of myocardium in the left ventricle, pro-
ducing mitral valve insufficiency. The pectinate muscles, tricuspid valve, and septomarginal tra-
becula are present in the right atrium and ventricle.

Front 16

16. A 75-year-old patient has been suffering
from lung cancer located near the cardiac notch,
a deep indentation on the lung. Which of the
following lobes is most likely to be excised?
(A) Superior lobe of the right lung
(B) Middle lobe of the right lung
(C) Inferior lobe of the right lung
(D) Superior lobe of the left lung
(E) Inferior lobe of the left lung

Back 16

16. The answer is D. The cardiac notch is a deep indentation of the anterior border of the supe-
rior lobe of the left lung. Therefore, the right lung is not involved.

Front 17

17. A thoracentesis is performed to aspirate an
abnormal accumulation of fluid in a 37-year-
old patient with pleural effusion. A needle
should be inserted at the midaxillary line be-
tween which of the following two ribs so as to
avoid puncturing the lung?
(A) Ribs 2 and 4
(B) Ribs 4 and 6
(C) Ribs 6 and 8
(D) Ribs 8 and 10
(E) Ribs 10 and 12

Back 17

17. The answer is D. A thoracentesis is performed for aspiration of fluid in the pleural cavity at or
posterior to the midaxillary line one or two intercostal spaces below the fluid level but not below the
ninth intercostal space, therefore between ribs 8 and 10. Other intercostals spaces are not preferred.

Front 18

18. A 6-year-old boy with tetralogy of Fallot
shows the pulmonary stenosis and the right
ventricular hypertrophy in addition to other
symptoms. Which of the following structures
is likely found in the hypertrophied heart
chamber?
(A) Sinus venarum
(B) Crista terminalis
(C) Pectinate muscles
(D) Septomarginal trabecula
(E) Valve of the coronary sinus

Back 18

18. The answer is D. The right ventricle contains the septomarginal trabecula, which forms a
bridge between the interventricular septum and the base of the anterior papillary muscle. The si-
nus venarum, crista terminalis, pectinate muscles, and valve of the coronary sinus are found in
the right atrium.

Front 19

19. A 33-year-old patient is suffering from a
sudden occlusion at the origin of the descend-
ing (thoracic) aorta. This condition would
most likely decrease blood flow in which of the
following intercostal arteries?
(A) Upper six anterior
(B) All of the posterior
(C) Upper two posterior
(D) Lower anterior
(E) Lower nine posterior

Back 19

19. The answer is E. The first two posterior intercostal arteries are branches of the highest (su-
perior) intercostal artery of the costocervical trunk; the remaining nine branches are from the
thoracic aorta. The internal thoracic artery gives off the upper six anterior intercostal arteries and
is divided into the superior epigastric and musculophrenic arteries, which gives off anterior in-
tercostal arteries in the seventh, eighth, and ninth intercostal spaces and ends in the tenth inter-
costal space where it anastomoses with the deep circumflex iliac artery.

Front 20

20. A 56-year-old patient recently suffered a
myocardial infarction in the area of the apex of
the heart. The occlusion by atherosclerosis is in
which of the following arteries?
(A) Marginal artery
(B) Right coronary artery at its origin
(C) Anterior interventricular artery
(D) Posterior interventricular artery
(E) Circumflex branch of the left coronary
artery

Back 20

20. The answer is C. The apex of the heart typically receives blood from the anterior interven-
tricular branch of the left coronary artery. The marginal artery supplies the right inferior margin
of the right ventricle, the right coronary artery at its origin supplies the right atrium and ventri-
cle, and the posterior interventricular artery and a circumflex branch of the left coronary artery
supply the left ventricle.

Front 21

21. A 75-year-old woman was admitted to a lo-
cal hospital, and bronchograms and radi-
ographs revealed a lung carcinoma in her left
lung. Which of the following structures are
characteristics of the cancerous lung?
(A) Horizontal fissure
(B) Groove for superior vena cava
(C) Middle lobe
(D) Lingula
(E) Larger capacity than the right

Back 21

21. The answer is D. The lingula is the tongue-shaped portion of the upper lobe of the left lung.
The right lung has a groove for the horizontal fissure, superior vena cava, and middle lobe and
has a larger capacity than the left lung.

Front 22

22. An 18-year-old girl is thrust into the steer-
ing wheel while driving. Which of the follow-
ing muscles is most likely damaged?
(A) Levator costarum
(B) Innermost intercostal muscle
(C) External intercostal muscle
(D) Diaphragm
(E) Muscles of the abdominal wall

Back 22

22. The answer is E. The abdominal muscles are the major muscles of expiration, whereas the
other distractors are muscles of inspiration.

Front 23

23. A 78-year-old patient presents with an ad-
vanced cancer in the posterior mediastinum.
The surgeons are in a dilemma as to how to
manage the condition. Which of the following
structures is most likely damaged?
(A) Brachiocephalic veins
(B) Trachea
(C) Arch of the azygos vein
(D) Arch of the aorta
(E) Hemiazygos vein

Back 23

23. The answer is E. The hemiazygos vein is located in the posterior mediastinum. The brachio-
cephalic veins, trachea, and arch of the aorta are located in the superior mediastinum, whereas
the arch of the azygos vein is found in the middle mediastinum.

Front 24

24. A 46-year-old patient comes to his doc-
tor's office and complains of chest pain and
headache. His computed tomography (CT)
scan reveals a tumor located just superior to
the root of the right lung. Blood flow in which
of the following veins is most likely blocked by
this tumor?
(A) Hemiazygos vein
(B) Arch of the azygos vein
(C) Right subclavian vein
(D) Right brachiocephalic vein
(E) Accessory hemiazygos vein

Back 24

24. The answer is B. The azygos vein arches over the root of the right lung and empties into the
superior vena cava. Other veins do not pass over the root of the right lung.

Front 25

25. A 21-year-old patient with a stab wound
reveals a laceration of the right vagus nerve
near the trachea in the superior mediastinum.
Which of the following conditions would most
likely be resulted from this lesion?
(A) Loss of sensation carried by the recurrent
laryngeal nerve
(B) Vasodilation of coronary arteries
(C) Dilation of the bronchial lumen
(D) Increase in cardiac rate
(E) Injury to parasympathetic preganglionic

Back 25

25. The answer is E. The vagus nerve carries parasympathetic preganglionic fibers to the thoracic
and abdominal viscera. The right recurrent laryngeal nerve is not affected by this injury because
it winds around the right subclavian artery and ascends in the neck. The parasympathetic nerve
in the vagus nerve decreases the heart rate, constricts the bronchial lumen, and causes vasocon-
striction of the coronary arteries.

Front 26

26. A 5-year-old boy with breathing difficulty,
chest pain, and cough was admitted to a local
hospital. The pediatrician who examined the
boy, along with laboratory results, diagnosed
the child as having cystic fibrosis. Which of the
following structures is most likely blocked?
(A) Trachea
(B) Primary bronchus
(C) Secondary or lobar bronchi
(D) Terminal bronchioles
(E) Alveolar duct

Back 26

26. The answer is D. Cystic fibrosis affects the respiratory system by causing an excess produc-
tion of viscous mucus by the bronchial glands, followed by mucous plugging and obstruction of
the respiratory airway, particularly a small airway, such as that in a child. The alveolar duct is a
part of this respiratory unit. The other structures are not affected because they are large airway
and are not usually obstructed and thus do not help in making the diagnosis.

Front 27

27. A 12-year-old boy was admitted to a local
hospital with a known history of heart problems. THORAX 187
His left ventricular hypertrophy could result
from which of the following conditions?
(A) A constricted pulmonary trunk
(B) An abnormally small left atrioventricular
(AV) opening
(C) Improper closing of the pulmonary valves
(D) An abnormally large right AV opening
(E) Stenosis of the aorta

Back 27

27. The answer is E. Stenosis of the aorta can cause left ventricular hypertrophy. Right ventric-
ular hypertrophy may occur as a result of pulmonary stenosis, pulmonary and tricuspid valve de-
fects, or mitral valve stenosis.

Front 28

28. A 31-year-old man was involved in a severe
automobile accident and suffered laceration of
the left primary bronchus. The damaged pri-
mary bronchus:
(A) Has a larger diameter than the right one
(B) Often receives more foreign bodies than
the right one
(C) Gives rise to the eparterial bronchus
(D) Is longer than the right primary bronchus
(E) Runs under the arch of the azygos vein

Back 28

28. The answer is D. The right primary bronchus is shorter than the left one and has a larger di-
ameter. More foreign bodies enter it via the trachea because it is more vertical than the left pri-
mary bronchus. The right primary bronchus runs under the arch of the azygos vein and gives rise
to the eparterial bronchus.

Front 29

29. A 62-year-old woman who is a heavy
smoker has an advanced lung cancer that
spread into her right third intercostal space
posterior to the midaxillary line. If cancer cells
are carried in the venous drainage, they would
travel first to which of the following veins?
(A) Superior vena cava
(B) Right superior intercostal vein
(C) Right brachiocephalic vein
(D) Azygos vein
(E) Hemiazygos vein

Back 29

29. The answer is B. The superior intercostal vein is formed by the union of the second, third,
and fourth posterior intercostal veins and drains into the azygos vein on the right and the bra-
chiocephalic vein on the left. The azygos vein drains into the superior vena cava. The hemiazy-
gos vein usually drains into the azygos vein.

Front 30

30. A radiologist examines posterior–anterior
chest radiographs of a 27-year-old victim of a
car accident. Which of the following structures
forms the right border of the cardiovascular sil-
houette?
(A) Arch of the aorta
(B) Pulmonary trunk
(C) Superior vena cava
(D) Ascending aorta
(E) Left ventricle

Back 30

30. The answer is C. A cardiovascular silhouette or cardiac shadow is the contour of the heart
and great vessels seen on posterior-anterior chest radiographs. Its right border is formed by the
superior vena cava, right atrium, and inferior vena cava; its left border is formed by the aortic arch
(aortic knob), pulmonary trunk, left auricle, and left ventricle. The ascending aorta becomes the
arch of the aorta and is found in the middle of the heart.

Front 31

31. A 37-year-old man is brought to the emer-
gency room complaining of severe chest pain.
His angiogram reveals thromboses of both bra-
chiocephalic veins. This condition would most
likely cause a dilation of which of the follow-
ing veins?
(A) Azygos
(B) Hemiazygos
(C) Right superior intercostal
(D) Left superior intercostal
(E) Internal thoracic

Back 31

31. The answer is D. The left superior intercostal vein is formed by the second, third, and fourth
posterior intercostal vein and drains into the left brachiocephalic vein. The right superior inter-
costal vein drains into the azygos vein, which in turn drains into the superior vena cava. The
hemiazygos vein drains into the azygos vein, whereas the internal thoracic vein empties into the
brachiocephalic vein.

Front 32

32. A cardiologist is on clinical rounds with
her medical students. She asks them, "During
the cardiac cycle, which of the following
events occurs?"
(A) Atrioventricular (AV) valves close during
diastole
(B) Aortic valve closes during systole
(C) Pulmonary valve opens during diastole
(D) Blood flow in coronary arteries is maxi-
mal during diastole
(E) Aortic valve closes at the same time as AV
valve

Back 32

32. The answer is D. During diastole the atrioventricular (AV) valves open and the aortic and
pulmonary valves close, whereas during systole the AV valves close and the aortic and pulmonary
valves open.

Front 33

33. Coronary angiographs of a 44-year-old
male patient reveal an occlusion of the circum-
flex branch of the left coronary artery. This pa-
tient has been suffering from myocardial in-
farction in which of the following areas?
(A) Right and left ventricles
(B) Right and left atria
(C) Interventricular septum
(D) Apex of the heart
(E) Left atrium and ventricle

Back 33

33. The answer is E. The left atrium and ventricle receive blood from the circumflex branch of
the left coronary artery. The interventricular septum and the apex of the heart are supplied by the
anterior interventricular branch of the left coronary artery. The right ventricle receives blood
from the anterior interventricular artery and the marginal branch of the right coronary artery.
The right atrium receives blood from the right coronary artery.

Front 34

34. A patient has a small but solid tumor in the
mediastinum, which is confined at the level of
the sternal angle. Which of the following struc-
tures would most likely be found at this level?
(A) Bifurcation of the trachea
(B) Beginning of the ascending aorta
(C) Middle of the aortic arch
(D) Articulation of the third rib with the
sternum
(E) Superior border of the superior medi-
astinum

Back 34

34. The answer is A. The sternal angle is the junction of the manubrium and the body of the
sternum. It is located at the level where the second rib articulates with the sternum, the trachea
bifurcates into the right and left bronchi, and the aortic arch begins and ends. It marks the end
of the ascending aorta and the beginning of the descending aorta, and it forms the inferior bor-
der of the superior mediastinum.

Front 35

35. A 37-year-old house painter fell from a lad-
der and fractured his left third rib and structures
with which it articulated. Which of the follow-
ing structures would most likely be damaged?
(A) Manubrium of the sternum
(B) Body of the second thoracic vertebra
(C) Spinous process of the third thoracic
vertebra
(D) Body of the fourth thoracic vertebra
(E) Transverse process of the second thoracic
vertebra

Back 35

35. The answer is B. The third rib articulates with the body of the sternum, bodies of the second
and third thoracic vertebrae, and transverse process of the third thoracic vertebra.

Front 36

36. A 45-year-old women presents with a tu-
mor confined to the posterior mediastinum.
This could result in compression of which of
the following structures?
(A) Trachea
(B) Descending aorta
(C) Arch of the aorta
(D) Arch of the azygos vein
(E) Phrenic nerve

Back 36

36. The answer is B. The descending aorta is found in both the superior and posterior medi-
astina. The superior mediastinum contains the trachea and arch of the aorta, and the middle me-
diastinum contains the ascending aorta, arch of the azygos vein, and main bronchi. The phrenic
nerve runs in the middle mediastinum.

Front 37

37. A 62-year-old patient with pericardial effu-
sion comes to a local hospital for aspiration of
pericardial fluid by pericardiocentesis. The nee-
dle is inserted into the pericardial cavity
through which of the following intercostal
spaces adjacent to the sternum?
(A) Right fourth intercostal space
(B) Left fourth intercostal space
(C) Right fifth intercostal space
(D) Left fifth intercostal space
(E) Right sixth intercostal space

Back 37

37. The answer is D. To aspirate pericardial fluid, the needle should be inserted into the peri-
cardial cavity through the fifth intercostals space just left to the sternum. Because of the cardiac
notch, the needle misses the pleura and lungs, but it penetrates the pericardium. Lung tissues lie
beneath the fourth and sixth intercostal spaces.

Front 38

38. The attending faculty in the coronary in-
tensive care unit (ICU) demonstrates to his stu-
dents a normal heart examination. The first
heart sound is produced by near-simultaneous
closure of which of the following valves?
(A) Aortic and tricuspid
(B) Aortic and pulmonary
(C) Tricuspid and mitral
(D) Mitral and pulmonary
(E) Tricuspid and pulmonary

Back 38

38. The answer is C. The first heart sound ("lub") is produced by the closure of the tricuspid and
mitral valves, whereas the second heart sound ("dub") is produced by the closure of the aortic and
pulmonary valves.

Front 39

39. A 27-year-old patient with Marfan's syn-
drome has an aneurysm of the aortic arch. This
may compress which of the following struc-
tures?
(A) Right vagus nerve
(B) Left phrenic nerve
(C) Right sympathetic trunk
(D) Left recurrent laryngeal nerve
(E) Left greater splanchnic nerve

Back 39

39. The answer is D. The left recurrent laryngeal nerve loops around the arch of the aorta near
the ligamentum arteriosum, whereas the right recurrent laryngeal nerve hooks around the right
subclavian artery. All other nerves are not closely associated with the aortic arch.

Front 40

40. A 47-year-old man with a known atrial fib-
rillation returns to see his cardiologist for fol-
low-up of his cardiac health. The right atrium
is important in this case because it:
(A) Receives blood from the oblique cardiac
vein
(B) Is associated with the apex of the heart
(C) Contains the sinoatrial node
(D) Receives the right pulmonary vein
(E) Is hypertrophied by pulmonary stenosis

Back 40

40. The answer is C. The sinoatrial (SA) and atrioventricular (AV) nodes are in the wall of the
right atrium and are not associated with the apex of the heart. The oblique cardiac vein drains
into the coronary sinus and the pulmonary veins empty into the left atrium. The right ventricle
is hypertrophied by the pulmonary stenosis.

Front 41

41. A 57-year-old patient has a heart murmur
resulting from the inability to maintain con-
stant tension on the cusps of the atrioventricu-
lar (AV) valve. Which of the following struc-
tures is most likely damaged?
(A) Crista terminalis
(B) Septomarginal trabecula
(C) Chordae tendineae
(D) Pectinate muscle
(E) Anulus fibrosus

Back 41

41. The answer is C. The chordae tendineae are tendinous strands that extend from the papil-
lary muscles to the cusps of the valve. The papillary muscles and chordae tendineae prevent the
cusps from being everted into the atrium during ventricular contraction.

Front 42

42. A 52-year-old patient with a history of my-
ocardial infarction exhibits a right coronary ar-
tery that is blocked by a fat globule after giving
off the right marginal artery. Which of the fol-
lowing structures may have oxygen deficiency?
(A) Right atrium
(B) Sinoatrial (SA) node
(C) Atrioventricular (AV) node
(D) Apex of the heart
(E) Anterior interventricular septum

Back 42

42. The answer is C. The atrioventricular (AV) node is supplied by the AV nodal artery, which
usually arises from the right coronary artery opposite the origin of the posterior interventricular
branch. The right atrium receives blood from the right coronary artery, the sinoatrial (SA) node
is supplied by the sinuatrial node artery, and the apex of the heart and AV septum are supplied
by the anterior IV artery.

Front 43

43. A surgical resident inadvertently ligates
the phrenic nerve instead of the accompanying
artery descending between the mediastinal
pleura and the pericardium without causing
any particular harm. Which of the following
arteries did he intend to ligate?
(A) Internal thoracic
(B) Musculophrenic
(C) Pericardiacophrenic
(D) Right coronary artery
(E) Superior (supreme) thoracic

Back 43

43. The answer is C. The phrenic nerve is accompanied by the pericardiacophrenic vessels of the
internal thoracic vessels and descends between the mediastinal pleura and the pericardium to
supply the pericardium, the mediastinal and diaphragmatic pleura, and the diaphragm. The in-
ternal thoracic artery descends directly behind the first six costal cartilages, just lateral to the ster-
num. The musculophrenic artery follows the costal arch on the inner surface of the costal carti-
lages. The right coronary artery runs between the right auricle and the pulmonary trunk and then
descends in the coronary sulcus between the right atrium and ventricle. The superior thoracic ar-
tery arises from the axillary artery and supplies the anterior first two intercostals space.

Front 44

44. A pulmonary fellow at a university hospi-
tal is asked to consult on a patient in respira-
tory failure. When the diaphragm contracts,
which of the following conditions should nor-
mally occur?
(A) Decreased thoracic volume
(B) Increased abdominal volume
(C) Increased lung volume
(D) Air flow out of the bronchi
(E) Increased thoracic pressure

Back 44

44. The answer is C. During inspiration the diaphragm contracts, increasing the vertical diame-
ter of the thorax and hence increasing lung volume, thoracic volume, and air flow into the
bronchi, and decreasing intrathoracic and intrapulmonary pressures and abdominal volume.

Front 45

45. A 32-year-old patient has a tension pneu-
mothorax that can be treated with needle aspi-
ration. To avoid an injury of the intercostal
neurovascular bundle, the needle may be in-
serted in which of the following locations?
(A) Above the upper border of the ribs
(B) Deep to the upper border of the ribs
(C) Beneath the lower border of the ribs
(D) Between the external and internal inter-
costals
(E) Through the transversus thoracis muscle

Back 45

45. The answer is A. The intercostal veins, arteries, and nerves run in the costal groove beneath
the inferior border of the ribs between the internal and innermost layers of muscles. The trans-
versus thoracis muscles are situated in the internal surface of the lower anterior thoracic wall.

Front 46

Questions 46-51: Choose the appropriate let-
tered site or structure in this computed to-
mography (CT) scan (page 189, top) of the
thorax from a 42-year-old man who com-
plains of chest pain and breathing problems.
His electrocardiogram (ECG) shows left ven-
tricular hypertrophy.

46. Stenosis of which structure may produce
left ventricular hypertrophy?

Back 46

46. The answer is C. Stenosis of the ascending aorta results in left ventricular hypertrophy.

Front 47

47. Which structure is most likely to be re-
moved by a pulmonary surgeon in a surgical
resection of a lobe (lobectomy) to remove lung
cancer in the apex of the right lung?

Back 47

47. The answer is B. During surgical treatment for cancer in the apex of the right lung by a
lobectomy, the right superior secondary (eparterial) bronchus should be removed.

Front 48

48. Which structure branches into the
bronchial arteries?

Back 48

48. The answer is E. The right and left bronchial arteries arise from the descending (thoracic)
aorta.

Front 49

49. Into which structure does the azygos vein
drain venous blood?

Back 49

49. The answer is A. The azygos vein drains venous blood into the superior vena cava.

Front 50

50. The left coronary artery arises from which
structure?

Back 50

50. The answer is C. The right and left coronary arteries arise from the ascending aorta.

Front 51

51. Which structure is crossed superiorly by
the aortic arch and left pulmonary artery?

Back 51

51. The answer is D. The left primary bronchus is crossed superiorly by the arch of the aorta and
the pulmonary artery.

Front 52

Questions 52-57: Choose the appropriate
lettered site or structure in this computed tomography (CT) scan (see below) of the
thorax. Which structure in this CT scan:

52. Can be removed in a surgical resection of a
lobe to remove lung cancer on the diaphrag-
matic surface?

Back 52

52. The answer is B. The right inferior lobar bronchus may be removed in a surgical resection of
the inferior lobe of the right lung that is in contact with the diaphragm.

Front 53

53. Becomes hypertrophied as result of the
pulmonary stenosis?

Back 53

53. The answer is C. Pulmonary stenosis results in right ventricular hypertrophy.

Front 54

54. Receives oxygenated blood via pulmonary
veins?

Back 54

54. The answer is E. The left atrium receives oxygenated blood from the lung by way of the pul-
monary veins.

Front 55

55. Lies on the right side of the aortic arch and
ascending aorta?

Back 55

55. The answer is A. The superior vena cava lies on the right side of the ascending aorta and the
arch of the aorta.

Front 56

56. Contains the septomarginal trabecula?

Back 56

56. The answer is C. The right ventricle contains the septomarginal trabecula.

Front 57

57. Takes its origin from the left ventricle and ends at the sternal angle?

Back 57

57. The answer is D. The ascending aorta takes its origin from the left ventricle and ends at the
level of the sternal angle by becoming the arch of the aorta.

Front 58

51. Which structure is crossed superiorly by the aortic arch and left pulmonary artery?

Back 58

51. The answer is D. The left primary bronchus is crossed superiorly by the arch of the aorta and the pulmonary artery.

Front 59

Questions 52-57: Choose the appropriate lettered site or structure in this computed tomography (CT) scan (see below) of the thorax. Which structure in this CT scan:

52. Can be removed in a surgical resection of a lobe to remove lung cancer on the diaphrag- matic surface?

Back 59

52. The answer is B. The right inferior lobar bronchus may be removed in a surgical resection of
the inferior lobe of the right lung that is in contact with the diaphragm.

Front 60

53. Becomes hypertrophied as result of the pulmonary stenosis?

Back 60

53. The answer is C. Pulmonary stenosis results in right ventricular hypertrophy.

Front 61

54. Receives oxygenated blood via pulmonary veins?

Back 61

54. The answer is E. The left atrium receives oxygenated blood from the lung by way of the pul-monary veins.

Front 62

55. Lies on the right side of the aortic arch and ascending aorta?

Back 62

55. The answer is A. The superior vena cava lies on the right side of the ascending aorta and the arch of the aorta.

Front 63

56. Contains the septomarginal trabecula?

Back 63

56. The answer is C. The right ventricle contains the septomarginal trabecula.

Front 64

57. Takes its origin from the left ventricle and ends at the sternal angle?

Back 64

57. The answer is D. The ascending aorta takes its origin from the left ventricle and ends at the
level of the sternal angle by becoming the arch of the aorta.