📚 Question Bank

Correct Answer: C

The semilunar valves guard the exits of the ventricles.

The pulmonary valve sits at the junction of the right ventricle and the pulmonary trunk. It consists of three semilunar cusps (anterior, right, and left). When the ventricle relaxes, the backward surge of blood fills these pocket-like cusps, slamming them shut to prevent backflow.

Correct Answer: C

The anterior interventricular artery, clinically known worldwide as the Left Anterior Descending (LAD) artery, travels down the anterior interventricular sulcus toward the apex.

It is the most critical vessel in the heart, supplying the anterior wall of both ventricles and the anterior two-thirds of the interventricular septum. A major blockage here is notoriously called the 'widow-maker'.

Correct Answer: B

In the fetal heart, the lungs are non-functional, so blood is shunted from the right atrium directly into the left atrium through a hole called the foramen ovale.

At birth, pressure changes in the heart force a flap over this hole, sealing it shut. The closed, scarred remnant of this hole is visible in the adult right atrium as the fossa ovalis.

Correct Answer: C

The heart wall has three layers:

• Endocardium (inner lining)
• Myocardium (middle muscle layer)
• Epicardium (outer layer)

Correct Answer: B

Dominance strictly refers to the origin of the Posterior Descending Artery (PDA), also known as the posterior interventricular artery, which supplies the posterior third of the interventricular septum.

In a right-dominant heart (the vast majority of people), the PDA branches off the Right Coronary Artery (RCA). If the PDA branches from the circumflex artery, the heart is left-dominant.

Correct Answer: C

The moderator band (anatomically the septomarginal trabecula) is a distinct, prominent bridge of muscle found only in the right ventricle.

It acts as an electrical shortcut. It carries the right bundle branch of the AV bundle straight across the chamber to the anterior papillary muscle, ensuring the papillary muscle contracts to tense the tricuspid valve before the main ventricular wall contracts.

Correct Answer: B

The heart feeds itself first!

The aortic valve has three semilunar cusps. The wall of the aorta bulges outward slightly behind each cusp, forming pockets called the aortic sinuses (of Valsalva). The right coronary artery arises from the right aortic sinus, and the left coronary artery arises from the left aortic sinus, ensuring maximum blood pressure delivery to the myocardium during ventricular diastole.

Correct Answer: C

This is a standard neurovascular pairing in the heart.

The great cardiac vein begins at the apex of the heart and travels up the anterior interventricular sulcus, perfectly shadowing the Left Anterior Descending (LAD) artery. It then wraps around the left side of the heart in the AV groove to become the coronary sinus.

Correct Answer: D

The middle cardiac vein drains the posterior surface of the heart.

It ascends in the posterior interventricular sulcus alongside the Posterior Descending Artery (PDA). (To complete the trio, the small cardiac vein accompanies the right marginal artery).

Correct Answer: C

The interventricular septum is mostly thick muscle, but its very superior-posterior portion is thin and fibrous (the membranous part).

This membranous part has a complex embryological origin, requiring the precise fusion of several different tissues (endocardial cushions, bulbar ridges). Because of this complex assembly, it is highly prone to failure, making membranous VSDs the most common type of congenital heart defect.

Correct Answer: C

The anterior wall of the right atrium and the right auricle feature parallel ridges of muscle that look like the teeth of a comb.

These are called the pectinate muscles (from the Latin 'pecten' meaning comb). They originate from the crista terminalis and increase the contractile power of the atrium without adding excessive wall mass.

Correct Answer: C

The main stem of the Left Coronary Artery is short but vital.

As soon as it reaches the left atrioventricular groove, it splits into two massive highways:

• The Left Anterior Descending (LAD) artery, which heads down the front of the heart.
• The Circumflex artery, which stays in the AV groove and wraps around to the back of the left ventricle.

Correct Answer: A

The Triangle of Koch is a surgical landmark used by electrophysiologists to locate and avoid (or ablate) the AV node.

Its borders are:

• Posteriorly: The opening of the coronary sinus.
• Anteriorly: The attachment of the septal leaflet of the tricuspid valve.
• Superiorly: The tendon of Todaro (a fibrous band running from the IVC valve to the central fibrous body).

Correct Answer: C

While the inflow tract of the right ventricle is rough and heavily ridged (trabeculae carneae), the outflow tract must be smooth to ensure laminar (non-turbulent) blood flow into the pulmonary artery.

This smooth, funnel-like superior portion of the right ventricle is called the infundibulum or conus arteriosus.

Correct Answer: C

Papillary muscle rupture is a catastrophic complication of a heart attack, causing massive mitral valve prolapse.

The anterolateral papillary muscle is generally safe because it has a dual blood supply (from the LAD and Circumflex). However, the posteromedial papillary muscle usually relies entirely on a single vessel—the Posterior Descending Artery (PDA). If the right coronary artery occludes, this muscle can die and snap under the strain of ventricular systole.

Correct Answer: C

The SA node needs a reliable blood supply to keep the heart beating.

In about 60% of people, the SA nodal artery branches off the Right Coronary Artery (RCA) very early in its course. In the other 40%, it arises from the left circumflex artery. This is why a proximal blockage of the RCA frequently causes bradycardia or SA nodal arrhythmias.

Correct Answer: B

The naming of the semilunar cusps is based on their position in the fetus before the heart fully rotates.

The Aortic Valve has one posterior cusp and two anterior cusps, named: Right, Left, and Posterior (non-coronary).
The Pulmonary Valve has one anterior cusp and two posterior cusps, named: Right, Left, and Anterior.

Correct Answer: C

The fossa ovalis is the scarred remnant of the fetal foramen ovale.

Because it was formerly a hole covered only by a thin flap of tissue (septum primum), it remains the thinnest, most membranous portion of the interatrial septum in the adult. Cardiologists use a transseptal puncture needle specifically at the fossa ovalis to safely cross into the left side of the heart without hitting the thicker, muscular walls.

Correct Answer: A

The cardiac skeleton is made of dense, non-conductive collagen.

It completely separates the muscular walls of the atria from the muscular walls of the ventricles. Because it does not conduct electricity, it acts as an insulator. It blocks the electrical wave from passing willy-nilly into the ventricles, forcing the signal to wait and pass exclusively through the designated 'toll booth': the AV node and Bundle of His. This ensures the atria contract before the ventricles.

Correct Answer: B

The crux of the heart is the cross-shaped intersection on the posterior aspect of the heart.

It is formed where the vertically oriented posterior interventricular sulcus meets the horizontally oriented coronary sulcus (atrioventricular groove). This exact point is critical because the AV nodal artery typically branches off the dominant coronary artery precisely at this junction.

Correct Answer: B

The left atrium forms the anatomical base (the flat posterior surface) of the heart.

It rests almost directly against the esophagus, separated only by the thin pericardial sac. This intimate relationship allows a TEE probe in the esophagus to get unobstructed, high-resolution ultrasound images of the left atrium and the mitral valve without the ribs or lungs getting in the way.

Correct Answer: C

Cardiac referred pain is a classic neuroanatomical phenomenon.

Visceral sensory (pain) fibers from the ischemic heart travel backward alongside the sympathetic fibers to enter the spinal cord at the T1-T4 (and sometimes T5) levels. Because the somatic sensory nerves for the chest wall and the medial arm (T1 dermatome) also enter at these same levels, the brain misinterprets the cardiac pain as originating from the left arm and chest.

Correct Answer: B

The anterior cardiac veins are a unique exception to the cardiac venous drainage rule.

They drain the anterior wall of the right ventricle. Instead of joining the great cardiac vein or the coronary sinus, these 2 to 5 small veins bridge across the anterior coronary sulcus and empty directly into the anterior wall of the right atrium.

Correct Answer: D Let's break down the compartments! The arm has two main muscular compartments. The anterior (flexor) compartment houses the biceps brachii, brachialis, and coracobrachialis. All three of these are innervated by the musculocutaneous nerve. You can think of it as the dedicated 'flexor nerve' of the arm. Why the others are incorrect: - The Radial nerve (A) exclusively supplies the posterior (extensor) compartment. - The Median (B) and Ulnar (C) nerves are just 'passengers' in the arm; they travel through it to reach the forearm and hand, but they do not innervate any muscles in the arm itself.