What is the nerve supply to the muscles of the flexor compartment of the arm?
What is the largest branch of the brachial plexus?
All are supplied by the anterior interosseous nerve except which of the following?
Which is the primary muscle causing supination of the forearm?
Which of the following statements about the great saphenous vein is true?
Line from midinguinal point to adductor tubercle represents?
The blood supply to femoral head is mostly by?
Main blood supply to the head and neck of femur comes from
Which of the following statements about the linea aspera is correct?
Sacral promontory is the landmark for
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 31: What is the nerve supply to the muscles of the flexor compartment of the arm?
- A. Musculocutaneous nerve (Correct Answer)
- B. Median nerve
- C. Radial nerve
- D. Ulnar nerve
Explanation: ***Musculocutaneous nerve*** - The **musculocutaneous nerve** is the primary nerve supplying all three muscles in the **flexor compartment of the arm**: the **biceps brachii**, **brachialis**, and **coracobrachialis**. - Its motor branches innervate these muscles, allowing for **flexion at the elbow** and **supination of the forearm**. *Median nerve* - The **median nerve** primarily innervates most muscles in the **flexor compartment of the forearm**, not the arm. - It plays a crucial role in **wrist and finger flexion**, as well as movements of the **thenar eminence**. *Radial nerve* - The **radial nerve** is the main nerve for the **extensor compartment of the arm and forearm**. - It is responsible for **elbow, wrist, and finger extension**. *Ulnar nerve* - The **ulnar nerve** primarily supplies intrinsic muscles of the hand and some flexor muscles in the forearm. - It has no motor supply to the muscles of the **flexor compartment of the arm**.
Question 32: What is the largest branch of the brachial plexus?
- A. Ulnar nerve
- B. Radial nerve (Correct Answer)
- C. Axillary nerve
- D. Median nerve
Explanation: ***Radial nerve*** - The **radial nerve** is considered the largest branch of the brachial plexus due to its extensive innervation of numerous muscles in the posterior compartment of the arm and forearm. - It arises from the **posterior cord** of the brachial plexus and innervates all the extensors of the arm and forearm, including the triceps brachii and supinator. *Ulnar nerve* - The ulnar nerve is a significant branch, but it is **smaller** in cross-sectional area and muscular distribution compared to the radial nerve. - It mainly innervates muscles of the **hand** and some forearm flexors. *Median nerve* - The median nerve is a large and clinically important nerve, formed by contributions from both the **lateral and medial cords**, but it is generally *not* considered the largest in terms of overall bulk or number of muscular branches. - It primarily innervates the **flexor muscles of the forearm** and some muscles of the hand (thenar eminence). *Axillary nerve* - The axillary nerve is one of the **smaller** terminal branches of the brachial plexus. - It primarily innervates the **deltoid** and **teres minor muscles**, and a small area of skin over the shoulder.
Question 33: All are supplied by the anterior interosseous nerve except which of the following?
- A. Flexor carpi ulnaris (Correct Answer)
- B. Pronator quadratus
- C. Flexor digitorum profundus (lateral half)
- D. Flexor pollicis longus
Explanation: ***Flexor carpi ulnaris*** - The **flexor carpi ulnaris** (FCU) is innervated by the **ulnar nerve**, not the anterior interosseous nerve [1]. - This is the correct answer as it is NOT supplied by the AIN. *Pronator quadratus* - The **pronator quadratus** IS supplied by the **anterior interosseous nerve**. - This deep muscle is responsible for **pronation of the forearm** and is one of the three muscles innervated by the AIN. *Flexor digitorum profundus (lateral half)* - The **lateral half of flexor digitorum profundus** (to index and middle fingers) IS supplied by the **anterior interosseous nerve**. - The medial half (to ring and little fingers) is supplied by the ulnar nerve. *Flexor pollicis longus* - The **flexor pollicis longus** (FPL) IS supplied by the **anterior interosseous nerve**. - This muscle is responsible for **flexion of the thumb's interphalangeal joint** and is one of the three muscles innervated by the AIN.
Question 34: Which is the primary muscle causing supination of the forearm?
- A. Brachioradialis
- B. Anconeus
- C. Biceps brachii
- D. Supinator (Correct Answer)
Explanation: ***Supinator*** - The **supinator muscle** is the **primary muscle** responsible for **supination** of the forearm, rotating the palm anteriorly or superiorly. - It is a deep muscle of the **posterior compartment** of the forearm. - Its action is especially prominent when **supinating against resistance** or in very slow movements, as it works synergistically with the biceps brachii. *Biceps brachii* - While the **biceps brachii** is also a powerful **supinator** of the forearm, especially when the elbow is flexed, it is a **secondary supinator**. - It is primarily a major **flexor** of the elbow, whereas the supinator is dedicated specifically to supination. *Brachioradialis* - The **brachioradialis** is primarily a **flexor** of the forearm at the elbow joint. - It helps to bring the forearm into a **mid-prone or mid-supine position** from either full pronation or full supination, but does not actively supinate. *Anconeus* - The **anconeus** is a small muscle that assists the **triceps brachii** in **extension of the forearm** at the elbow. - It helps to **stabilize the elbow joint** and slightly abducts the ulna during pronation, but has no role in supination.
Question 35: Which of the following statements about the great saphenous vein is true?
- A. It begins at lateral end of dorsal venous arch
- B. It runs anterior to medial malleolus (Correct Answer)
- C. Terminates into popliteal vein
- D. It is accompanied by the sural nerve
Explanation: **It runs anterior to medial malleolus** - The **great saphenous vein** originates from the medial end of the **dorsal venous arch** of the foot and ascends anterior to the **medial malleolus** [1]. - This anatomical relationship makes it accessible for various clinical procedures, such as **venous cutdown** for rapid intravenous access [1]. *It begins at lateral end of dorsal venous arch* - The **great saphenous vein** actually begins at the **medial end** of the dorsal venous arch, not the lateral end [1]. - The **small saphenous vein** arises from the lateral end of the dorsal venous arch [1]. *It is accompanied by the sural nerve* - The **sural nerve** typically accompanies the **small saphenous vein**, not the great saphenous vein, in the posterior leg [1]. - The **saphenous nerve**, a branch of the femoral nerve, accompanies the great saphenous vein throughout its course in the leg. *Terminates into popliteal vein* - The **great saphenous vein** normally terminates by draining into the **femoral vein** in the femoral triangle, not the popliteal vein [1]. - The **small saphenous vein** is the one that typically drains into the popliteal vein [1].
Question 36: Line from midinguinal point to adductor tubercle represents?
- A. Inferior epigastric artery
- B. Femoral artery (Correct Answer)
- C. Superior epigastric artery
- D. None of the options
Explanation: The line from the **midinguinal point** to the **adductor tubercle** accurately maps the anatomical course of the **femoral artery** in the thigh. This anatomical landmark is crucial for palpating the **femoral pulse** and locating the artery for clinical procedures like catheter insertion. *Inferior epigastric artery* - The **inferior epigastric artery** originates from the external iliac artery and ascends superiorly in the anterior abdominal wall [1]. - Its course is significantly more medial and superior, far from the line described. *Superior epigastric artery* - The **superior epigastric artery** is a terminal branch of the internal thoracic artery, descending into the rectus sheath in the upper abdomen [1]. - Its location is entirely within the anterior abdominal wall, high above the inguinal region. *None of the options* - This option is incorrect because the line from the midinguinal point to the adductor tubercle clearly represents the anatomical course of the femoral artery. - The other arteries listed are not found along this specific anatomical path.
Question 37: The blood supply to femoral head is mostly by?
- A. Lateral epiphyseal artery
- B. Medial epiphyseal artery
- C. Artery of ligamentum teres
- D. Profunda femoris (Correct Answer)
Explanation: ***Profunda femoris*** - The profunda femoris artery (deep femoral artery) gives rise to the **medial and lateral circumflex femoral arteries**, which are the primary blood supply to the femoral head in adults - Specifically, the **medial circumflex femoral artery** and its branches (lateral epiphyseal arteries and retinacular arteries) form an extracapsular arterial ring and penetrate the joint capsule to supply the femoral head - The profunda femoris is thus the main parent vessel responsible for femoral head blood supply *Lateral epiphyseal artery* - This artery is a branch of the **medial circumflex femoral artery**, which originates from the profunda femoris - While it directly supplies the femoral head and is the dominant terminal branch, it represents a more specific component of the arterial network rather than the main source vessel - It provides blood to the lateral and superior portions of the femoral head *Medial epiphyseal artery* - This artery is also a branch of the circumflex femoral arteries, which originate from the profunda femoris - It contributes to the blood supply but is less dominant than the lateral epiphyseal branches - Similar to lateral epiphyseal artery, it is part of the retinacular arterial system *Artery of ligamentum teres* - The **artery of the ligamentum teres** (foveal artery) is an inconsistent and often small vessel, typically a branch of the **obturator artery** or medial circumflex femoral artery - While it contributes to blood supply especially in children, its contribution is usually minor in adults and often insufficient to sustain the femoral head alone - It enters through the fovea capitis and its contribution diminishes with age
Question 38: Main blood supply to the head and neck of femur comes from
- A. Lateral circumflex femoral artery
- B. Medial circumflex femoral artery (Correct Answer)
- C. Artery of ligamentum teres
- D. Popliteal artery
Explanation: ***Medial circumflex femoral artery*** - The **medial circumflex femoral artery** is the primary arterial supply to the **head and neck of the femur**, particularly via its **retinacular branches**. - These branches ascend along the femoral neck within the joint capsule, supplying most of the femoral head. *Lateral circumflex femoral artery* - The **lateral circumflex femoral artery** primarily supplies the muscles of the **anterior compartment of the thigh**, including the quadriceps femoris. - While it contributes to anastomoses around the hip, its direct supply to the femoral head and neck is less significant than the medial circumflex. *Artery of ligamentum teres* - The **artery of the ligamentum teres** (foveal artery) supplies a small, variable portion of the **femoral head**, mainly in children. - Its contribution to the overall blood supply to the adult femoral head and neck is often negligible or absent. *Popliteal artery* - The **popliteal artery** is located in the **popliteal fossa** behind the knee joint and is the continuation of the femoral artery. - Its branches supply the structures around the knee and lower leg, not the femoral head and neck.
Question 39: Which of the following statements about the linea aspera is correct?
- A. Forms lateral border of femur
- B. Continues as gluteal tuberosity (Correct Answer)
- C. Forms medial border of femur
- D. None of the options
Explanation: Correct: Continues as gluteal tuberosity - The lateral lip of the linea aspera continues superiorly as the gluteal tuberosity (also called the gluteal ridge or line) - This anatomical continuation is a key feature of the femur's posterior surface - The gluteal tuberosity serves as the attachment site for the gluteus maximus muscle - The medial lip continues superiorly as the pectineal line (spiral line), which then joins the lesser trochanter Incorrect: Forms lateral border of femur - The linea aspera is located on the posterior surface of the femoral shaft, not on the lateral border - The lateral border of the femur is formed by the smooth lateral surface of the shaft - The linea aspera's lateral lip is a posterior ridge, distinct from the true lateral border Incorrect: Forms medial border of femur - The linea aspera is on the posterior aspect of the femur, not the medial border - The medial border of the femur is formed by the smooth medial surface of the shaft - The medial lip of the linea aspera is a muscle attachment site on the posterior surface, not a border
Question 40: Sacral promontory is the landmark for
- A. Termination of presacral nerve (Correct Answer)
- B. None of the options
- C. Origin of inferior mesenteric artery
- D. Origin of superior mesenteric artery
Explanation: ***Termination of presacral nerve*** - The **sacral promontory** is the key anatomical landmark where the **superior hypogastric plexus** (presacral nerve) **bifurcates** into the right and left hypogastric nerves. - This bifurcation typically occurs at the level of the **sacral promontory**, making it a crucial landmark for **presacral neurectomy** procedures. - The superior hypogastric plexus is formed by the fusion of sympathetic fibers and lies anterior to the L5 vertebra and sacral promontory. - Clinically important for **pelvic surgery** and **pain management** procedures. *Origin of superior mesenteric artery* - The **superior mesenteric artery (SMA)** originates from the **anterior aspect of the abdominal aorta** at the level of the **L1 vertebra**. - This is far superior to the sacral promontory, which is at the lumbosacral junction (L5-S1). - The SMA supplies the midgut derivatives. *Origin of inferior mesenteric artery* - The **inferior mesenteric artery (IMA)** originates from the **anterior aspect of the abdominal aorta** at the level of the **L3 vertebra**. - This is also well above the sacral promontory. - The IMA supplies the hindgut derivatives. *None of the options* - This is incorrect as the sacral promontory is indeed a recognized landmark for the **bifurcation/termination of the presacral nerve** (superior hypogastric plexus).