S1 Practice Questions for Lab Practical Pt. 2

1. You see a pharmaceutical commercial advertising a revolutionary drug to treat Mitral Valve Prolapse that "tugs on the heartstrings." Its mechanism of action most likely involves which muscles that act on the chordae tendinae?

Pectinate muscles

Trabeculae carnae

Papillary muscles

Myocardium

Papillary muscles tense the chordae tendinae during systole, thereby preventing
valve prolapsed (pushback into the atria).

Explanation

Papillary muscles tense the chordae tendinae during systole, thereby preventing
valve prolapsed (pushback into the atria).

2. How many shunts are typically involved in healthy fetal circulation?

1

2

3

4

0

Fetal circulation: Placenta-Left umbilical vein-ductus venosus (1st shunt)-Inferior
vena cava-Right atrium-Foramen ovale (2nd shunt)-LA-LV-Aorta-Ductus arteriosus
(3rd shunt to pulmonary trunk)-Common iliac arteries-Umbilical arteries-Placenta

Explanation

Fetal circulation: Placenta-Left umbilical vein-ductus venosus (1st shunt)-Inferior
vena cava-Right atrium-Foramen ovale (2nd shunt)-LA-LV-Aorta-Ductus arteriosus
(3rd shunt to pulmonary trunk)-Common iliac arteries-Umbilical arteries-Placenta

3. What is the embryological origin(s) of the right atrium?

Primitive atrium alone

Primitive atrium and right horn of sinus venosus

Primitive atrium and left horn of sinus venosus

Primitive atrium and pulmonary vein outgrowth

Sinus venosus alone

Remember the right atrium has 2 embryological origins. The atrium proper forms
the rough part and the right horn of sinus venosus forms the smooth part.

Explanation

Remember the right atrium has 2 embryological origins. The atrium proper forms
the rough part and the right horn of sinus venosus forms the smooth part.

4. During open heart surgery, you are instructed by the surgeon to clamp the outflow vessels of the heart. The anatomical space through which you will place the clamp is called:

The oblique pericardial sinus

The coronary sulcus

The transverse pericardial sinus

The sulcus terminale

The coronary sinus

is correct because the transverse pericardial sinus is the space behind the
ascending aorta and pulmonary trunk, but anterior to the SVC.

Explanation

is correct because the transverse pericardial sinus is the space behind the
ascending aorta and pulmonary trunk, but anterior to the SVC.

5. A 20-year-old male presents to you with a high steppage gait on the right side. You suspect that he uses this compensatory gain because he suffers from foot drop. What scenario is the most plausible regarding his condition?

He was playing basketball and landed on an inverted foot

He was playing football and someone fell on his everted foot

He was slashed with a knife near the lateral knee by a hoodlum on a skateboard

He was playing beer pong and passed out using his arm as a pillow

He was playing soccer and made a quick right turn as he ran after the ball

Damage to the common fibular nerve results in foot drop. This nerve is most
commonly injured near the fibular head or neck because it is very superficial at this
location, and in close proximity to the bone.

Explanation

Damage to the common fibular nerve results in foot drop. This nerve is most
commonly injured near the fibular head or neck because it is very superficial at this
location, and in close proximity to the bone.

6. While performing pericardiocentesis, you unintentionally pierce a vessel running parasternally within the internal thorax. What vessel has most likely been damaged?

Thoracic aorta

5th anterior intercostal artery

Inferior vena cava

Internal thoracic artery

Superior epigastric artery

The internal thoracic artery (aka internal mammary artery) is a branch of the
subclavian artery; it runs immediately lateral to the sternum (i.e., parasternally) along
the internal thorax, and thus may be damaged during pericardiocentesis. This artery
has 2 terminal branches: the superior epigastric and musculophrenic arteries.

Explanation

The internal thoracic artery (aka internal mammary artery) is a branch of the
subclavian artery; it runs immediately lateral to the sternum (i.e., parasternally) along
the internal thorax, and thus may be damaged during pericardiocentesis. This artery
has 2 terminal branches: the superior epigastric and musculophrenic arteries.

7. One of the recurrent laryngeal nerves is usually shorter than the other. Which one and why?

Left; starts at ligamentum arteriosum

Left; starts at left subclavian artery

Right; starts at ligamentum arteriosum

Right; starts at right subclavian artery

The right recurrent laryngeal nerve loops under the right subclavian artery, while
the left RLN loops under the ligamentum arteriosum (between aortic arch and
pulmonary trunk); this makes the right one significantly shorter than the left one.

Explanation

The right recurrent laryngeal nerve loops under the right subclavian artery, while
the left RLN loops under the ligamentum arteriosum (between aortic arch and
pulmonary trunk); this makes the right one significantly shorter than the left one.

8. What structure carries the Right Bundle Branch to the anterior papillary muscles?

Crista terminalis

Sulcus terminale

Supraventricular crest

Septomarginal trabecula

Conus arteriosus

The septomarginal trabecular (aka moderator band) carries right bundle branch
fibers to the anterior papillary muscle.

Explanation

The septomarginal trabecular (aka moderator band) carries right bundle branch
fibers to the anterior papillary muscle.

9. The Middle Cardiac Vein travels with which artery?

Right Coronary Artery

Right Marginal Artery

Posterior Interventricular Artery

Left Coronary Artery

Left Anterior Descending Artery

Left Circumflex Artery

Middle cardiac vein runs in the posterior interventricular groove

Explanation

Middle cardiac vein runs in the posterior interventricular groove

10. A 50-year-old patient presents with a chief complaint of facial swelling which began several weeks ago. She also reports shortness of breath (dyspnea) with exertion. On examination, the patient is tender over the mediastinum. X-rays and fine needle aspiration reveal a mass consistent with a thymoma. What is the likely mechanism responsible for the patient's symptoms?

Lung atelectasis

Compressed aortic arch

Underproduction of T lymphocytes

Compressed left brachiocephalic vein

Recurrent laryngeal nerve damage

A thymoma will occupy the most anterior area of the superior mediastinum, that is
just deep to the manubrium of the sternum. And just deep to the thymus gland we
find the left brachiocephalic vein, which would likely be compressed in an
overgrowth of the thymus. This compression may prevent blood from draining from
the left side of the head and neck as well as reduce venous return, producing
various symptoms similar to a superior vena cava syndrome.

Explanation

A thymoma will occupy the most anterior area of the superior mediastinum, that is
just deep to the manubrium of the sternum. And just deep to the thymus gland we
find the left brachiocephalic vein, which would likely be compressed in an
overgrowth of the thymus. This compression may prevent blood from draining from
the left side of the head and neck as well as reduce venous return, producing
various symptoms similar to a superior vena cava syndrome.

11. The radiologist reports back to you on a patient who presented to the clinic with shortness of breath (dyspnea) and chest discomfort: right middle lobe (RML) pneumonia. You know from your days in the anatomy lab that the RML has two segments. What are the functionally equivalent lobe and segments on the left?

Lower - superior and inferior segments

Lower - medial and lateral segments

Lingual - superior and inferior segments

Lingual - medial and lateral segments

Oblique - superior and inferior segments

Oblique - medial and lateral segments

Although the left lung has only the superior and inferior lobes, functionally the
lingular portion is equivalent to the right lung's middle lobe. The lingular portion
consists of superior lingular and inferior lingular segments. Remember that even
without a "lingual lobe" the segments are autonomous for blood supply and can be
surgically removed if necessary.

Explanation

Although the left lung has only the superior and inferior lobes, functionally the
lingular portion is equivalent to the right lung's middle lobe. The lingular portion
consists of superior lingular and inferior lingular segments. Remember that even
without a "lingual lobe" the segments are autonomous for blood supply and can be
surgically removed if necessary.

12. The right pulmonic border of the heart consists mainly of what chamber?

Right Atrium

Left Atrium

Right Ventricle

Left Ventricle

Right atrium forms right border of heart; on x-rays, this appears as a mostly
vertical line.

Explanation

Right atrium forms right border of heart; on x-rays, this appears as a mostly
vertical line.

13. A patient presents to the emergency department with shortness of breath (dyspnea) and cold clammy hands. Your team determines that the patient suffers from a cardiac tamponade (due to blood within the pericardial sac, putting pressure on the heart). You are asked to perform a pericardiocentesis to save the patient's life. You select your needle and insert it in which location in order to minimize risk?

Left parasternal 2nd intercostal space

Right parasternal 2nd intercostal space

Right infrasternal angle

Left infrasternal angle

Left 5th intercostal space in the mid-axillary line

The pericardium can be accessed from the anterior thorax through the Bare Area,
so called because the cardiac notch in the left lung (and its pleural covering) leaves
part of the pericardium exposed at this location. This is an area where the left lung
deflects laterally creating a dull space in the thorax. It is located in the Left
infrasternal angle, which is between the xiphoid process and costal margin, and can
also be accessed through the left 5th and 6th intercostal space immediately to the left
of the sternum.

Explanation

The pericardium can be accessed from the anterior thorax through the Bare Area,
so called because the cardiac notch in the left lung (and its pleural covering) leaves
part of the pericardium exposed at this location. This is an area where the left lung
deflects laterally creating a dull space in the thorax. It is located in the Left
infrasternal angle, which is between the xiphoid process and costal margin, and can
also be accessed through the left 5th and 6th intercostal space immediately to the left
of the sternum.

14. A 50 year-old male presents to his family physician for a well checkup. His past medical history is significant for Rheumatic Fever as a child. During heart auscultation, you hear a holosystolic murmur loudest in the left 5th intercostal space, midclavicular line. What do you suspect?

Mitral Regurgitation

Mitral Stenosis

Tricuspid Regurgitation

Aortic Stenosis

holosystolic murmur loudest over apex is likely mitral regurgitation, which can be
caused by rheumatic heart disease.

Explanation

holosystolic murmur loudest over apex is likely mitral regurgitation, which can be
caused by rheumatic heart disease.

15. The base of the heart is mostly occupied by which chamber?

Right Atrium

Left Atrium

Right Ventricle

Left Ventricle

The opposite of the apex is the base of the heart, which is mainly comprised of the
left atrium.

Explanation

The opposite of the apex is the base of the heart, which is mainly comprised of the
left atrium.

16. Which tarsal bone articulates with more than one metatarsal bone?

Medial Cuneiform

Intermediate cuneiform

Lateral cuneiform

Cuboid

Calcaneus

Cuboid articulates with the 4th and 5th metatarsals

Explanation

Cuboid articulates with the 4th and 5th metatarsals

17. The superficial fibular nerve is severed near its origin. What motor deficit(s) would you expect in a patient with this injury?

Weak dorsiflexion, weak eversion

Weak dorsiflexion, absent eversion

Weak eversion

Absent eversion

No motor deficit because this nerve is purely sensory

Superficial fibular nerve innervates the lateral compartment muscles, both of
which are evertors of the foot (as well as very weak plantarflexors). Fibularis tertius is innervated by deep fibular nerve (intact in this patient), and so it can still provide
some ability for eversion.

Explanation

Superficial fibular nerve innervates the lateral compartment muscles, both of
which are evertors of the foot (as well as very weak plantarflexors). Fibularis tertius is innervated by deep fibular nerve (intact in this patient), and so it can still provide
some ability for eversion.

18. A 2-year-old child presents with a ventricular septal defect, but he does not have Tetralogy of Fallot. With this congenital anomaly, which valve is most likely to be insufficient?

Tricuspid valve

Mitral valve

Aortic valve

Pulmonary valve

All valves

The tricuspid valve has 3 cusps (anterior, posterior, septal); because it
has a septal cusp, it is most likely affected by a ventricular septal defect. The
majority of VSDs occur in the membranous part, which is near to where the septal
cusp would be attached to the septum via the septal papillary muscles.

Explanation

The tricuspid valve has 3 cusps (anterior, posterior, septal); because it
has a septal cusp, it is most likely affected by a ventricular septal defect. The
majority of VSDs occur in the membranous part, which is near to where the septal
cusp would be attached to the septum via the septal papillary muscles.

19. The inferior border of the heart is mainly supplied directly by what artery?

Right Coronary Artery

Right Marginal Artery

Posterior Interventricular Artery

Left Coronary Artery

Left Anterior Descending Artery

Left Circumflex Artery

Right marginal artery (aka acute marginal artery) is a branch of the right coronary
artery and runs along the inferior border, supplying most of the cardiac tissues along
this region.

Explanation

Right marginal artery (aka acute marginal artery) is a branch of the right coronary
artery and runs along the inferior border, supplying most of the cardiac tissues along
this region.

S1 Practice Questions For Lab Practical Pt. 2