Chapter 4: Cardiovascular Anatomy and Physiology
Which of the following statements regarding normal cardiac anatomy is TRUE?
(A) The pulmonic valve is attached by chordae tendinae to the right ventricle.
(B) The coronary sinus empties into the left atrium.
(C) A patent foramen ovale is found in 25% to 30% of adults.
(D) The ligamentum arteriosum connects the aorta to the pulmonary vein.
(E) The root of the aorta is positioned between the left auricle and the pulmonary trunk.
The answer is C. The aortic and pulmonic valves are semilunar valves, with three cusps each. They are positioned at the base of the aorta and pulmonary trunk, respectively, and allow blood flow out of the ventricles. Closure of these valves at the end of systole by back pressure in the aorta and pulmonary trunk causes the second heart sound. There are no chordae tendinae attached to the semilunar valves; these structures connect the papillary muscles of the left and right ventricles to the cusps of the mitral and tricuspid valves, respectively.
The coronary sinus, the major drainage vessel of the heart, empties into the right atrium between the inferior vena cava and the tricuspid valve on the inferior aspect of the interatrial septum. Its valve is termed the Thebesian valve.
Both autopsy and transesophageal echocardiographic studies have found a prevalence of patent foramen ovale of approximately 25% to 30%. There appear to be no difference in prevalence rates between males and females. In patients with cryptogenic stroke, PFO prevalence is higher, between 40% and 45%.
The ligamentum arteriosum is the fibrous remains of the embryonic ductus arteriosus, a shunt that allows blood entering the pulmonary trunk to flow to the aorta prior to birth, as resistance to flow within the pulmonary system is high. It becomes fibrosed within three weeks of birth.
The aortic root is positioned in between the right auricle and the pulmonary trunk. The right auricle is located on the opposite side of the pulmonary trunk.
Ref: Fuster V, Walsh R, Harrington R. Hurst's The Heart. 13th ed. New York, NY: McGraw Hill; 2011.
Which of the following coronary vessels supplies the majority of the interventricular septum?
(B) left circumflex artery
(C) left anterior descending artery
(D) right coronary artery
(E) posterior descending artery