Heart Practice Quiz

Which structures lie in the coronary sulcus?

Circumflex artery Coronary sinus Right coronary artery Left coronary artery ---------------- 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.

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?

2 ------- Remember, the sternal angle is where the costal cartilage of the second rib attaches to the sternum. This is a significant landmark!

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:

Anterior interventricular (Left anterior descending) artery -------------------- 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.

Blockage of which of the following arteries would lead to ischemia of the apex of the heart?

Anterior interventricular (descending) artery ----------------- The anterior interventricular artery is a branch of the left coronary artery. It supplies both ventricles as well as the interventricular septum. It also reaches the apex, supplying that area as well. The left circumflex artery is the other major branch of the left coronary artery. It supplies the posterior surface of the left ventricle, but does not reach the apex of the heart. The right coronary artery has two major branches: the right marginal and the posterior interventricular artery. (The right coronary also gives off two smaller branches to the SA node and the AV node.) The right marginal artery supplies the right ventricle, while the posterior IV artery supplies the interventricular septum and the two ventricles. Neither of these arteries provides a major source of blood to the apex of the heart.

Which valves would be open during ventricular systole?

Aortic and pulmonary valves ------------------- Remember that ventricular systole is the period when the ventricles are contracting. This contraction forces blood out of the heart, which pushes the aortic and pulmonary valves open. During systole, the tricuspid and mitral valves are closed. They are prevented from prolapsing (being pushed back into the atrium) by the chordae tendinae and papillary muscles.

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?

Aortic valve -------------- The four valves of the heart can be auscultated at very distinct spaces. The aortic valve, which separates the left ventricle from the aorta, can be auscultated in the 2nd right intercostal space, just lateral to sternal angle. Since this is the space where the murmur is heard, the problem must be with the aortic valve. The mitral valve, which separates the left atrium from the left ventricle, can be auscultated in the left 5th intercostal space, slightly below the nipple. 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. 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.

Traumatic, acceleration/deceleration injuries to the aorta usually occur where its mobile and fixed portions meet. This would be at the:

At the ligamentum arteriosum --------------- 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.

Which posterior mediastinal structure is most closely applied to the posterior surface of the pericardial sac?

Esophagus -------------- 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.

During fetal life and sometimes persisting into the adult there is an opening between the right and left atria; this opening is called the:

Foramen ovale ----------------- The foramen ovale is an opening in the interatrial septum which exists in the fetus. This opening and the ductus arteriosus serve as two shunts which divert blood away from the developing lungs. Both should close soon after birth. The coronary sinus is the large vein on the posterior surface of the heart which drains into the right atrium. 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 sinus venosus and truncus arteriosus are structures in the developing heart that will be covered in embryology.

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?

Great cardiac vein ------------- 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.

The heart sound associated with the mitral valve is best heard:

In the 5th left intercostal space ----------------------- The four valves of the heart can be auscultated at very distinct spaces. The mitral valve can be ausculatated in the left 5th intercostal space, slightly below the nipple.The aortic valve can be ausculatated in the 2nd right intercostal space, just lateral to sternal angle. The pulmonary valve can be auscultated in the 2nd left intercostal space, just lateral to sternal angle. The tricuspid valve can be auscultated in the 4th left intercostal space, just lateral to sternum.

Describe the right atrioventricular valve.

It is open during ventricular diastole. ---------------- 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.

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:

Just to the left of the xiphisternal junction ------------------ 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.

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?

Left recurrent laryngeal nerve -------------- 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.

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?

Mitral valve ------------- 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.

A hand slipped behind the heart at its apex can be extended upwards until stopped by a line of pericardial reflection that forms the:

Oblique pericardial sinus ----------------- 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.

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:

Oblique sinus --------------- 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.

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?

Posterior interventricular --------------------- 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.

Elevated systolic blood pressure in the right ventricle suggests stenosis of which valve?

Pulmonary valve ------------- 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!

Which heart valve has leaflets described as "anterior, left and right"?

Pulmonary valve --------------- 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.

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?

Pulmonary valve ------------------ 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. Learn these points of auscultation very well, because you will be using them again and again!

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?

Right ventricle ------------- Remember, the anterior surface, or sternocostal surface, of the heart is mostly made up of the right ventricle. So, if an object punctured the sternum,it would be likely to pierce the right ventricle.

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?

Right ventricle -------------- The right ventricle forms the anterior (sternocostal) surface of the heart. So, this is the surface of the heart that lies against the sternum and would be injured following a crushing blow to the sternum. There are 2 other surfaces of the heart of which you should be aware. The diaphragmatic surface of the heart is formed by the left ventricle, with a little bit of the right ventricle. This is the surface of the heart which is in contact with the diaphragm. The pulmonary surface of the heart is on the left side of the heart. It is mostly formed by the left ventricle.

Which chamber's anterior wall forms most of the sternocostal surface of the heart?

Right ventricle ------------------ 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.

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?

Right ventricle --------------- Since the right ventricle forms the anterior, or sternocostal, surface of the heart, this would be the chamber most likely to be injured by the blade. This is also the surface of the heart most likely to be injured by an insult to the anterior chest wall.

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?

Thoracic duct -------------- 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.

Which structure contains postganglionic sympathetic fibers?

Ulnar nerve ------------- 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).

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?

Xiphoid area, just off the sternum ---------------- 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!