Which artery supplies the anterior part of the interventricular septum?
Which of the following does not directly drain into right atrium?
The structure which lies outside the femoral sheath is:
What is the medial boundary of the cubital fossa?
Insertion of levator scapulae is?
What is the primary lymphatic drainage pathway of the ovary?
Which of the following structures does not pass through the superior thoracic aperture?
What is the embryological origin of the ligamentum arteriosum?
Base of the heart is formed by?
Right border of heart is formed by?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 31: Which artery supplies the anterior part of the interventricular septum?
- A. Right coronary artery
- B. Posterior descending coronary artery
- C. Left anterior descending artery (LAD) (Correct Answer)
- D. None of the options
Explanation: ***Left anterior descending artery (LAD)*** - The **LAD** is a branch of the **left main coronary artery** and is also known as the "widowmaker" due to its critical supply to a large portion of the left ventricle and the interventricular septum [1]. - It gives rise to **septal branches** that typically supply the anterior two-thirds of the interventricular septum [1]. *Right coronary artery* - The **right coronary artery (RCA)** primarily supplies the **right ventricle**, the right atrium, the SA node (in 60% of people), and the AV node (in 90% of people). - It typically supplies the **inferior wall** of the left ventricle and the posterior one-third of the interventricular septum [1]. *Posterior descending coronary artery* - The **posterior descending artery (PDA)** arises from the **RCA** (in approximately 85% of individuals, known as right dominance) or less commonly from the circumflex artery (in left dominance) [1]. - It supplies the **posterior one-third** of the interventricular septum and typically the inferior wall of the left ventricle [1]. *None of the options* - This option is incorrect because the **LAD** clearly and predominantly supplies the anterior part of the interventricular septum.
Question 32: Which of the following does not directly drain into right atrium?
- A. Inferior vena cava
- B. Great cardiac vein (Correct Answer)
- C. Anterior cardiac vein
- D. Venae cordis minimi
Explanation: ***Great cardiac vein*** - The **great cardiac vein** drains into the **coronary sinus**, which then empties into the right atrium [1]. - It does not drain directly into the right atrium, distinguishing it from the other options. *Inferior vena cava* - The **inferior vena cava** is one of the major vessels that drains directly into the **right atrium**. - It carries deoxygenated blood from the lower body to the right atrium. *Anterior cardiac vein* - The **anterior cardiac veins** drain directly into the **right atrium**. - They tend to drain the anterior surface of the right ventricle. *Venae cordis minimi* - Also known as **Thebesian veins**, these are small veins that drain directly into the cardiac chambers, including the **right atrium**. - They represent a direct communication between the myocardial capillaries and the cardiac chambers.
Question 33: The structure which lies outside the femoral sheath is:
- A. Genitofemoral nerve
- B. Femoral vein
- C. Femoral artery
- D. Femoral nerve (Correct Answer)
Explanation: ***Femoral nerve*** - The **femoral nerve** lies lateral to the femoral artery and is therefore situated outside the **femoral sheath**, which encloses the femoral artery, femoral vein, and lymphatic vessels [2]. - It originates from the lumbar plexus (L2-L4) and provides motor innervation to the quadriceps femoris and sensory innervation to the anterior thigh and medial leg. *Femoral artery* - The **femoral artery** is a primary content of the **femoral sheath**, occupying the most lateral compartment. - It is a continuation of the external iliac artery and is a major blood supply to the lower limb. *Femoral vein* - The **femoral vein** lies within the **femoral sheath**, positioned medial to the femoral artery. - It is the primary vein responsible for draining blood from the lower limb and eventually becomes the external iliac vein. *Genitofemoral nerve* - The **genitofemoral nerve** typically emerges on the anterior surface of the psoas major muscle and then usually divides into genital and femoral branches [1]. - While its femoral branch supplies sensory innervation to the skin over the femoral triangle, it does not course within the femoral sheath itself but rather anterior to it or outside its immediate vicinity [1].
Question 34: What is the medial boundary of the cubital fossa?
- A. Brachioradialis
- B. Pronator teres (Correct Answer)
- C. Supinator
- D. None of the options
Explanation: ***Pronator teres*** - The **pronator teres muscle** forms the **medial boundary** of the cubital fossa, running obliquely from the medial epicondyle to the lateral side of the radius. - This muscle defines the medial aspect of the triangular space at the anterior elbow. *Brachioradialis* - The **brachioradialis** muscle forms the **lateral boundary** of the cubital fossa. - It arises from the humerus and inserts into the distal radius, helping to delineate the region laterally. *Supinator* - The **supinator muscle** is located deep within the forearm and is not a direct boundary of the cubital fossa. - It lies on the posterior aspect of the radius and ulna, deep to some of the cubital fossa contents. *None of the options* - This option is incorrect because the **pronator teres** clearly defines the medial boundary of the cubital fossa.
Question 35: Insertion of levator scapulae is?
- A. Lateral border of scapula
- B. Suprolateral part of scapula
- C. Superior part of medial scapula border (Correct Answer)
- D. Inferior angle of scapula
Explanation: ***Superior part of medial scapula border*** - The **levator scapulae muscle** originates from the **transverse processes of C1-C4 vertebrae** and **inserts** onto the superior part of the medial border of the scapula, between the **superior angle and the spine of the scapula**. - Its main actions are to **elevate** and **rotate** the scapula downward. *Lateral border of scapula* - The **lateral border of the scapula** primarily serves as the attachment site for muscles that move the **humerus**, such as the **teres major** and **teres minor**. - The levator scapulae has no direct insertion on the lateral border. *Suprolateral part of scapula* - This general description is vague and does not precisely identify the insertion point of the levator scapulae. - While it's located superiorly, the specific insertion is on the **medial border**, not broadly "suprolateral." *Inferior angle of scapula* - The **inferior angle of the scapula** is the insertion point for muscles like the **latissimus dorsi** (occasionally) and a key landmark for muscles involved in **scapular rotation**, such as the **serratus anterior**. - The levator scapulae is located much more superiorly and inserts onto the medial border at a higher level than the inferior angle.
Question 36: What is the primary lymphatic drainage pathway of the ovary?
- A. Deep inguinal
- B. Superficial inguinal
- C. Obturator
- D. Paraaortic (Correct Answer)
Explanation: ***Paraaortic*** - The **ovaries** develop embryologically in the abdominal cavity near the kidneys, and their lymphatic drainage follows the **ovarian vessels** (which arise from the aorta). - Lymph drains primarily to the **paraaortic (lumbar) lymph nodes** located along the **aorta** in the retroperitoneum at the level of L1-L2. - This is clinically important in ovarian cancer staging and treatment planning. *Deep inguinal* - The **deep inguinal lymph nodes** primarily drain the deep structures of the lower limb, perineum, and external genitalia. - They do not receive lymphatic drainage directly from the ovaries. *Superficial inguinal* - The **superficial inguinal lymph nodes** drain the skin of the lower abdomen, buttocks, perineum, external genitalia, and the superficial lower limb. - The ovaries are internal intra-abdominal organs and do not drain into these nodes. *Obturator* - The **obturator lymph nodes** are pelvic lymph nodes that primarily drain pelvic structures such as the bladder, uterine body, cervix, and upper vagina. - While adjacent to pelvic organs, they are not the primary drainage site for the ovaries, which drain superiorly along the ovarian vessels to the paraaortic nodes.
Question 37: Which of the following structures does not pass through the superior thoracic aperture?
- A. Right vagus
- B. Right brachiocephalic artery
- C. Thoracic duct
- D. Right recurrent laryngeal nerve (Correct Answer)
Explanation: ***Right recurrent laryngeal nerve*** - The **right recurrent laryngeal nerve** loops around the **right subclavian artery** in the neck [1] and ascends into the neck to innervate the larynx. - It does not descend into the thorax before recurring, thus it does not pass through the superior thoracic aperture [1]. *Right vagus* - The **right vagus nerve** passes through the superior thoracic aperture anterior to the right subclavian artery and enters the thorax. - It then descends posterior to the right brachiocephalic vein and superior vena cava before supplying thoracic and abdominal viscera. *Right brachiocephalic artery* - The **right brachiocephalic artery** (also known as the brachiocephalic trunk) is the first branch of the aortic arch and passes superiorly through the superior thoracic aperture. - It gives rise to the right common carotid artery and right subclavian artery in the neck. *Thoracic duct* - The **thoracic duct** ascends from the abdomen through the posterior mediastinum, passes through the superior thoracic aperture to enter the neck [2]. - In the neck, it arches laterally and empties into the left subclavian vein, or the junction of the left internal jugular and subclavian veins.
Question 38: What is the embryological origin of the ligamentum arteriosum?
- A. Remnant of the ductus arteriosus (Correct Answer)
- B. Remnant of the ductus venosus
- C. Remnant of the ductus utriculosaccularis
- D. Remnant of the ductus reuniens
Explanation: ***Remnant of the ductus arteriosus*** - The **ductus arteriosus** is a fetal blood vessel connecting the **pulmonary artery** to the **aorta**, bypassing the non-functional lungs [1]. - After birth, due to increased oxygen tension and decreased prostaglandins, it typically constricts and obliterates, forming the **ligamentum arteriosum** [2]. *Remnant of the ductus venosus* - The **ductus venosus** is a fetal shunt connecting the **umbilical vein** to the **inferior vena cava**, bypassing the liver's circulatory bed [2]. - After birth, it closes and becomes the **ligamentum venosum**, not the ligamentum arteriosum [2]. *Remnant of the ductus utriculosaccularis* - This is an **inner ear structure** connecting the utricle and saccule in the membranous labyrinth. - It is **not a cardiovascular structure** and has no relation to the ligamentum arteriosum. *Remnant of the ductus reuniens* - The **ductus reuniens** (also called ductus utriculosaccularis) is an **inner ear structure**, not a fetal cardiovascular shunt. - It has **no remnant** related to the ligamentum arteriosum or cardiovascular system.
Question 39: Base of the heart is formed by?
- A. Right atrium
- B. Right ventricle
- C. Left atrium (Correct Answer)
- D. Left ventricle
Explanation: ***Left atrium*** - The **left atrium** forms the major part of the **base of the heart**, receiving the four pulmonary veins. [1] - It lies in the posterior-superior aspect of the heart and is separated from the thoracic vertebrae by the **pericardium** and the **esophagus**. *Right atrium* - The **right atrium** forms the right border of the heart and receives deoxygenated blood from the **superior and inferior vena cava**. - It primarily forms part of the **anterior surface** of the heart, not the base. *Right ventricle* - The **right ventricle** forms a large part of the **anterior surface** and inferior border of the heart. - It is responsible for pumping blood to the **pulmonary circulation** but does not form the base. *Left ventricle* - The **left ventricle** forms the **apex** of the heart and much of its **left border** and **diaphragmatic surface**. - Its primary role is to pump oxygenated blood into the **systemic circulation**.
Question 40: Right border of heart is formed by?
- A. Right ventricle
- B. Right atrium (Correct Answer)
- C. SVC
- D. IVC
Explanation: ***Right atrium*** - The **right atrium** forms the major part of the **right border of the heart** as viewed in a posteroanterior (PA) chest X-ray. - Its position is along the right sternal margin, extending from the level of the third costal cartilage superiorly to the sixth costal cartilage inferiorly. *Right ventricle* - The **right ventricle** primarily forms the **anterior surface** and part of the inferior border of the heart. - It contributes minimally, if at all, to the visible right border in a standard PA view. *SVC* - The **superior vena cava (SVC)** drains into the right atrium and is located superior to it. - While it's adjacent to the right border, it does **not form the actual right border of the heart itself**. *IVC* - The **inferior vena cava (IVC)** drains into the right atrium from below. - It is positioned inferiorly and posteriorly, and therefore **does not form the right border** of the heart in a PA view.