1.
Blockage of which of the following arteries would lead to ischemia of the apex of the heart?
Correct Answer
A. Anterior interventricular (descending)
Explanation
Blockage of the anterior interventricular (descending) artery would lead to ischemia of the apex of the heart. This artery, also known as the left anterior descending artery, supplies blood to the anterior wall of the left ventricle, including the apex. Ischemia occurs when there is a reduced blood flow to a particular area, leading to a lack of oxygen and nutrients. Therefore, if this artery is blocked, the apex of the heart will not receive adequate blood supply, resulting in ischemia.
2.
If the ductus arteriosus does not spontaneously close off soon after birth (to become the ligamentum arteriosum), it may have to be surgically ligated. When clamping or ligating it, what important structure immediately behind it must be identified and saved?
Correct Answer
D. Left recurrent laryngeal nerve
Explanation
The left recurrent laryngeal nerve leaves the vagus nerve and loops under the arch of the aorta near the ligamentum arteriosum/ductus arteriosis. When performing surgery in this area, like the repair of a patent ductus arteriosis, a surgeon must be very careful to identify and preserve the left recurrent laryngeal nerve. If this nerve is damaged, it may lead to paralysis of the left vocal fold and cause hoarseness in the patient. This is a very significant complication that you want to remember!
The arch of the azygos vein is located on the right side of the body and would not be damaged by surgery near the aortic arch. The internal thoracic artery is a branch of the subclavian artery and is not near the ductus arteriosis.
The left phrenic nerve, which innervates the diaphragm, is lateral to the vagus nerve and would not be damaged in this procedure.
The left superior intercostal vein lies lateral to the vagus and aortic arch, so it would not be disturbed by surgery.
3.
A hand slipped behind the heart at its apex can be extended upwards until stopped by a line of pericardial reflection that forms the:
Correct Answer
D. Oblique pericardial sinus
Explanation
The oblique pericardial sinus is an area of the pericardial cavity located behind the left atrium of heart where the serous pericardium reflects onto the inferior vena cava and pulmonary veins. If you slide your fingers under the heart, they will be in this space. The other pericardial sinus that you should be familiar with is the transverse sinus. The transverse sinus is an area of the pericardial cavity located behind the aorta and pulmonary trunk and anterior to the superior vena cava. It separates the outflow vessels from inflow vessels.
The cardiac notch is an indentation in the superior lobe of the left lung which creates the lingula.
The costamediastinal recess is an area in the pleural sac where the costal pleura changes to the mediastinal pleura.
Finally, the hilar reflection is the reflection of pleura at the root of the lung, where visceral pleura on the lung becomes continuous with the parietal mediastinal pleura.
4.
A stethoscope placed over the left second intercostal space just lateral to the sternum would be best positioned to detect sounds associated with which heart valve?
Correct Answer
B. Pulmonary
Explanation
The best place to listen to heart valves is not at their actual sternocostal projections. If you place your stethoscope exactly where a valve is located, you may not hear anything because the valve might be deep in the chest or the sound might be muffled by bone or cartilage. Instead, you want to listen to the valves by putting your stethescope at a point downstream from the valve where you can hear the blood flowing and colliding with the muscular chest wall.
There are points of auscultation for all four heart valves: Pulmonic: left second intercostal space, lateral to the sternal angle; Aortic: right second intercostal space, lateral to the sternal angle;
Mitral: left fifth intercostal space, 8cm away from the midline;
Tricuspid: left fourth intercostal space, just lateral to the sternum.
5.
Which valves would be open during ventricular systole?
Correct Answer
A. Aortic and pulmonary
Explanation
During ventricular systole, the ventricles contract and pump blood out of the heart. The aortic valve is responsible for allowing blood to flow from the left ventricle into the aorta, while the pulmonary valve allows blood to flow from the right ventricle into the pulmonary artery. Therefore, during ventricular systole, the aortic and pulmonary valves would be open to allow blood to be pumped out of the heart and into the respective arteries.
6.
Which chamber's anterior wall forms most of the sternocostal surface of the heart?
Correct Answer
D. Right ventricle
Explanation
The heart has three important surfaces: an anterior surface, a diaphragmatic surface, and a pulmonary surface. The anterior surface, or sternocostal surface, is mostly made up of the right ventricle. The diaphragmatic surface is mostly the left ventricle, but a little bit of the right ventricle sits on the diaphragm as well. Finally, the pulmonary surface, which is on the left, is mostly made up of the left ventricle.
7.
A 3rd-year medical student was doing her first physical exam. In order to properly place her stethoscope to listen to heart sounds, she palpated bony landmarks. She began at the jugular notch, then slid her fingers down to the sternal angle. At which rib (costal cartilage) level were her fingers?
Correct Answer
B. 2
Explanation
The sternal angle is located at the level of the second rib. Therefore, when the medical student slid her fingers down to the sternal angle, her fingers were at the level of the second rib.
8.
A patient involved in an automobile accident presents with a sharp object puncture of the middle of the sternum at about the level of the 4th or 5th costal cartilage. If the object also penetrated pericardium and heart wall, which heart chamber would most likely be damaged?
Correct Answer
D. Right ventricle
Explanation
If the object penetrated the pericardium and heart wall, the heart chamber most likely to be damaged is the right ventricle. The right ventricle is located in the lower right portion of the heart and is the chamber responsible for pumping oxygen-depleted blood to the lungs. In this case, the puncture injury would have directly affected the right ventricle, potentially causing damage to its structure and function.
9.
Which statement is true of the right atrioventricular valve?
Correct Answer
B. It is open during ventricular diastole
Explanation
Ventricular diastole is the period when the ventricles relax and fill with blood. So, the AV valves need to be open at this time so that blood can flow from the atria to the ventricles. The right AV valve is called the tricuspid valve--it has three leaflets. The left AV valve is called the mitral valve and has two leaflets. Remember, the right side of the heart is pumping blood to the lungs so that it can be oxygenated. So, the blood flowing through the right AV valve will be deoxygenated, while the blood flowing through the left AV valve will be oxygenated.
Finally, remember that the chordae tendineae and the papillary muscles do not pull the AV valves open! These structures serve to prevent the valves from prolapsing during systole.
10.
A 23-year-old male injured in an industrial explosion was found to have multiple small metal fragments in his thoracic cavity. Since the pericardium was torn inferiorly, the surgeon began to explore for fragments in the pericardial sac. Slipping her hand under the heart apex, she slid her fingers upward and to the right within the sac until they were stopped by the cul-de-sac formed by the pericardial reflection near the base of the heart. Her fingertips were then in the:
Correct Answer
D. Oblique sinus
Explanation
The oblique sinus is an area of the pericardial cavity located behind the left atrium of the heart where the serous pericardium reflects onto the inferior vena cava and pulmonary veins. If you slide your fingers under the heart, they will be in the oblique sinus. The other pericardial sinus that you should be familiar with is the transverse sinus. The transverse sinus is an area of the pericardial cavity located behind the aorta and pulmonary trunk and anterior to the superior vena cava. It separates the outflow vessels from inflow vessels.
The coronary sinus is the large vein on the posterior surface of the heart which drains into the right atria. It receives blood from the great, middle, and small cardiac veins, the oblique vein of the left atrium, and the left posterior ventricular vein.
The coronary sulcus is the groove on the heart which separates the atria from the ventricles. Many arteries and veins run in this sulcus.
The costomediastinal recess is an area in the pleural sac where the costal pleura changes to the mediastinal pleura.
11.
An elderly lady suffers a coronary occlusion and subsequently it is noted that there is a complete heart block (that is, the right and left bundles of the conduction system have been damaged). The artery most likely involved is the:
Correct Answer
C. Anterior interventricular (Left anterior descending)
Explanation
The right and left bundles of conduction travel in the interventricular septum. So, the artery that has been occluded must be the one that supplies the interventricular septum. The most important source of blood to the interventricular septum is the anterior interventricular artery, a branch of the left coronary artery.
Although the posterior interventricular artery partially supplies blood to the interventricular septum, it might not be enough to support the tissue in this region.
The circumflex branch of the left coronary artery provides blood to the posterior surface of the left ventricle.
The acute marginal branch of the right coronary artery provides blood to the right ventricle.
12.
During fetal life and sometimes persisting into the adult there is an opening between the right and left atria; this opening is called the:
Correct Answer
C. Foramen ovale
Explanation
During fetal development, there is a temporary opening between the right and left atria called the foramen ovale. This opening allows blood to bypass the lungs since the fetus receives oxygen from the mother's blood through the placenta. After birth, when the baby starts breathing on its own, the foramen ovale usually closes, allowing blood to flow normally through the heart and lungs. However, in some individuals, the foramen ovale may persist into adulthood, causing a condition known as a patent foramen ovale.
13.
Which event occurs during ventricular diastole?
Correct Answer
A. Filling of coronary arteries
Explanation
During ventricular diastole, the heart muscles relax, and the ventricles are filled with blood from the atria. This relaxation phase allows the coronary arteries, which supply oxygenated blood to the heart muscle itself, to fill with blood and nourish the heart. Therefore, the filling of coronary arteries occurs during ventricular diastole.
14.
Which heart valve has leaflets described as "anterior, left and right"?
Correct Answer
B. Pulmonary
Explanation
The correct answer is Pulmonary. The pulmonary valve is located between the right ventricle and the pulmonary artery. It has three leaflets, which are described as anterior, left, and right. These leaflets open and close to allow blood to flow from the right ventricle to the pulmonary artery and prevent backflow.
15.
In preparation for thoracic surgery, a median sternal splitting procedure was carried out. But an improper depth setting on the saw blade resulted in a slight nick on the underlying sternocostal surface of the heart. Which heart chamber would most likely have been opened had the blade completely penetrated this wall?
Correct Answer
D. Right ventricle
Explanation
If the blade had completely penetrated the sternocostal surface of the heart, the most likely heart chamber to have been opened would be the right ventricle. The right ventricle is located on the anterior surface of the heart, closest to the sternum.
16.
The sound associated with tricuspid stenosis (narrowing) in a 40-year-old male would be best heard at which location on the anterior chest wall?
Correct Answer
E. XipHoid area, just off the sternum
Explanation
It's best to listen to sounds associated with the tricuspid valve at the fourth left intercostal space, just lateral to the sternum. The answer that comes the closest to this is E. What would you hear in the other spaces? Below the left nipple, in the fifth intercostal space, you would be auscultating the mitral valve. This is also the valve that you can hear at the apex of the heart. The right 2nd intercostal space near the sternum is the site for auscultating the aortic valve. Finally, it would be difficult to hear anything over the sternal angle, since the stethoscope would be over bone, which would blunt any sounds!
17.
Blockage of blood flow in the proximal part of the anterior interventricular artery could deprive a large area of heart tissue of blood supply, unless a substantial retrograde flow into this artery develops via an important anastomosis with which other artery?
Correct Answer
C. Posterior interventricular
Explanation
The anterior interventricular artery and posterior interventricular artery travel on the anterior and posterior surfaces of the interventricular groove. These two vessels often anastamose. If there was a very extensive anastamosis between the anterior and posterior interventricular arteries, it is possible that the posterior interventricular artery might supply the tissue usually fed by the anterior interventricular artery. The other arteries listed would not be able to anastamose with anterior interventricular artery; they supply other areas of the heart.
18.
Traumatic, acceleration/deceleration injuries to the aorta usually occur where its mobile and fixed portions meet. This would be at the:
Correct Answer
A. At the ligamentum arteriosum
Explanation
The ligamentum arteriosum is the point where the left pulmonary artery connects with the undersurface of aortic arch. It is a remnant of the fetal ductus arteriosus, which shunted blood away from the developing lungs. Because the aorta is tethered to the pulmonary artery by the ligamentum arteriosum, the part of the aorta near the ligamentum is vulnerable to damage in a traumatic acceleration/deceleration injury - it could pull away and tear. The other answer choices do not describe points of the aorta where a mobile and fixed portion meet. Therefore, these parts of the aorta would not be vulnerable to this type of traumatic injury.
19.
Which structure does NOT lie in the coronary sulcus?
Correct Answer
D. Right marginal artery
Explanation
The coronary sulcus is the groove which separates the atria from the ventricles. The right and left coronary arteries, circumflex artery, and coronary sinus all lie in this groove. The right marginal artery is a branch of the right coronary artery which lies on the right ventricle and supplies that chamber of the heart
20.
Which structure contains postganglionic sympathetic fibers?
Correct Answer
D. Ulnar nerve
Explanation
When a nerve fiber reaches the sympathetic chain, there are three things that can happen. First, the nerve fibers can enter a ganglia, synapse at that level, and rejoin the spinal nerve via the grey ramus communicans. Second, the preganglionic nerve fibers can travel up or down the trunk, synapse in a ganglia at another level, and then rejoin a spinal nerve. This is how sympathetic fibers join spinal nerves at the cervical and lumbar levels, which are above and below the lateral horn. Third, some preganglionic fibers do not synapse in the trunk and, instead, form splanchnic nerves. These nerves descend into the abdomen and synapse in other ganglia.
The greater thoracic splanchnic nerve contains preganglionic fibers that are destined to synapse in the celiac plexus. The recurrent laryngeal nerve provides motor and sensory innervation to the upper esophagus and pharynx. Finally, the vagus nerve is a mixed nerve that carries preganglionic parasympathetic fibers. None of these nerves carry postganglionic sympathetic fibers.
The ulnar nerve innervates muscles of the hand, arm, and provides some sensory innervation to skin of the hand and arm. It is derived from ventral rami of spinal nerves, all of which carry postganglionic sympathetic fibers (for vascular smooth muscle, arrector pili muscles, and sweat glands).
21.
Which posterior mediastinal structure is most closely applied to the posterior surface of the pericardial sac?
Correct Answer
C. EsopHagus
Explanation
The esophagus is closely related to the posterior surface of the pericardial sac.
After coming from the heart, the aorta arches over the left pulmonary artery and left bronchus. Eventually, just above the diaphragm, this vessel is posterior to the esophagus.
The azygos vein, on the right side of the thorax, arches over the right pulmonary artery and bronchus. It is also posterior to the esophagus.
The thoracic duct is posterior to the esophagus as well and does not contact the pericardial sac.
Finally, the trachea is superior to the heart.
22.
In obstruction of the superior or inferior vena cava, venous blood is returned to the heart by an alternate route via the azygos vein, which becomes dilated in the process. Which of the following structures might it compress as a result?
Correct Answer
D. Thoracic duct
Explanation
Below the level of the sternal angle, the thoracic duct lies posterior to the esophagus, between the azygos vein and the descending aorta. So, if the azygos vein became dilated, it could impinge on the thoracic duct. The trachea is superior to the azygos vein, which loops over the right bronchus before emptying into the superior vena cava. This means that a dilated azygos vein would have little impact on the trachea. Because the azygos is on the right side of the body, it could not compress anything at the root of the left lung. The right phrenic nerve is anterior to the azygos vein. The descending aorta is much larger and more muscular than the azygos vein, so it is unlikely that it would be compressed by this much smaller structure.
23.
Elevated systolic blood pressure in the right ventricle suggests stenosis of which valve?
Correct Answer
C. Pulmonary
Explanation
In these sorts of questions, you need to identify the valve immediately distal to the area of high pressure. This is the valve that must be blocked, because you can assume that blood is backing up into the area where the pressure is high. In this case, pressure is high in the right ventricle. So, there must be stenosis of the pulmonic valve, which allows blood to leave the right ventricle and travel to the lung.
If there was stenosis of the aortic valve, pressure would be high in the left ventricle. If there was stenosis of the tricuspid valve, pressure would be high in the right atrium. If there was stenosis of the mitral valve, pressure would be high in the left atrium. If you understand the path of blood flow in the heart, you can understand all these scenarios!
24.
During examination of a 62-year-old man, the senior resident tells you to put your stethoscope on the left 5th intercostal space, slightly below the nipple, and listen for a clearly audible murmur. You hear it distinctly and know it must be associated with severe stenosis of which heart valve?
Correct Answer
B. Mitral
Explanation
The four valves of the heart can be auscultated at very distinct spaces, and you should make sure that you know these!
The mitral valve, which separates the left atrium from the left ventricle, can be ausculatated in the left 5th intercostal space, slightly below the nipple. This is where this patient's murmur is heard.
The tricuspid valve, which separates the right atrium from the right ventricle, can be auscultated in the 4th left intercostal space, just lateral to sternum.
The aortic valve, which separates the left ventricle from the aorta, can be ausculatated in the 2nd right intercostal space, just lateral to sternal angle.
The pulmonary valve, which separates the right ventricle from the pulmonary artery, can be auscultated in the 2nd left intercostal space, just lateral to sternal angle.
25.
A 26-year-old male is brought into the emergency room after having been kicked in the chest by a horse. After examination, it is concluded that the most likely immediate danger is cardiac tamponade (bleeding into the pericardial sac). You prepare to draw off some of the blood from the sac to relieve the pressure on the heart. The safest site at which to insert the needle of the syringe in order to miss the pleura would be:
Correct Answer
B. Just to the left of the xipHisternal junction
Explanation
When fluid accumulates in the pericardial sac, it is necessary to remove that fluid by performing a pericardiocentesis. A needle is inserted just to the left of the xiphisternal junction, and the needle passes superiorly to enter the pericardial sac. Then, the fluid can be aspirated into the needle.
26.
A 22-year-old male involved in an automobile accident presents with symptoms suggestive of myocardial contusion due to blunt trauma, specifically compression of the sternocostal surface of the heart by the sternum when his chest hit the steering wheel. Which heart chamber was most likely damaged?
Correct Answer
D. Right ventricle
Explanation
In a blunt trauma to the chest, the heart can be compressed between the sternum and the spine, causing damage to the heart chambers. The right ventricle is the most likely chamber to be damaged in this scenario because it is located closest to the sternum. The left atrium and left ventricle are located more posteriorly in the chest and are less likely to be affected by direct compression from the sternum. The right atrium is also more posteriorly located and is therefore less likely to be damaged compared to the right ventricle.
27.
While attempting to suture the distal end of a coronary bypass onto the anterior interventricular artery, the surgeon accidentally passed the needle through the adjacent vein. Which vein was damaged?
Correct Answer
C. Great cardiac vein
Explanation
To answer this question, you need to know that the anterior interventricular artery lies in the anterior interventricular sulcus. Then, you need to identify the vein that also lies in the anterior interventricular sulcus. And that vein is the great cardiac vein. The anterior cardiac vein lies on the surface of the right atrium--it drains directly into the right atrium. The coronary sinus is located in the coronary (atrioventricular) sulcus--it is formed by the union of the great cardiac vein and the oblique vein of the left atrium, and it drains blood directly into the right atrium. The middle cardiac vein is located in the posterior interventricular sulcus--it accompanies the posterior interventricular artery. The small cardiac vein courses through the coronary sulcus with the right coronary artery.
OR just remember "too bad he died, he was a GREAT LAD" (use an irish accent)
28.
While listening to a patient's heart sounds with a stethoscope, you identify a high-pitched sound in the second right intercostal space, just lateral to the edge of the sternum. Your correct conclusion is that you have detected stenosis of which heart valve?
Correct Answer
A. Aortic
Explanation
Based on the location of the high-pitched sound in the second right intercostal space, just lateral to the edge of the sternum, the correct conclusion is that the stenosis is of the aortic valve. The aortic valve is typically heard in this area during auscultation, and a high-pitched sound suggests narrowing or stenosis of the valve.
29.
The heart sound associated with the mitral valve is best heard:
Correct Answer
D. In the fifth left intercostal space
Explanation
The mitral valve is best heard in the fifth left intercostal space. This is because the mitral valve is located between the left atrium and left ventricle of the heart, and the fifth left intercostal space is the area where the apex of the heart is located. The apex is the bottom tip of the heart and is the point where the mitral valve can be best auscultated.
30.
Which heart valve has right, left, and anterior cusps?
Correct Answer
D. Pulmonary
Explanation
The leaflets of the pulmonic valve are named anterior, left, and right, according to their orientation.
The leaflets of the aortic valve are named posterior, left, and right, with the left and right aortic sinuses above these leaflets giving off their respective coronary arteries.
The mitral valve has anterior and posterior cusps, while the tricuspid valve has septal, anterior, and smaller posterior cusps.