All of the following muscles have dual nerve supply except which one?
Which muscle is not part of the superficial anterior compartment of the forearm?
Which of the following structures is not found in the midpalmar space?
Axillary nerve is accompanied by which artery ?
What is the nerve supply to the muscles of the flexor compartment of the arm?
Which is the primary muscle causing supination of the forearm?
All are supplied by the anterior interosseous nerve except which of the following?
Interosseous membrane of forearm is pierced by?
Which of the following statements about the great saphenous vein is true?
Which muscles are known as 'Triceps surae'?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 61: All of the following muscles have dual nerve supply except which one?
- A. Pectoralis major
- B. Flexor digitorum profundus
- C. Biceps brachii (Correct Answer)
- D. Subscapularis
Explanation: ***Biceps brachii*** - The **biceps brachii** muscle is solely innervated by the **musculocutaneous nerve (C5, C6, C7)**. - This muscle is a prime mover for forearm supination and elbow flexion and does not receive nerve supply from any other nerve. *Subscapularis* - The **subscapularis** muscle has a dual nerve supply from both the **upper and lower subscapular nerves (C5, C6)**. - This dual innervation ensures motor control of the subscapularis, which is an important medial rotator of the humerus. *Pectoralis major* - The **pectoralis major** muscle receives a dual nerve supply from both the **medial and lateral pectoral nerves** [1]. - The **lateral pectoral nerve** primarily supplies the clavicular head, while the **medial pectoral nerve** supplies both the sternocostal head and a portion of the clavicular head [1]. *Flexor digitorum profundus* - The **flexor digitorum profundus** muscle has a dual nerve supply from the **median nerve** (innervating the lateral half for digits 2 and 3) and the **ulnar nerve** (innervating the medial half for digits 4 and 5). - This dual innervation allows for independent or coordinated flexion of the distal phalanges of the fingers.
Question 62: Which muscle is not part of the superficial anterior compartment of the forearm?
- A. FDS
- B. FCR
- C. Palmaris longus
- D. Flexor pollicis longus (FPL) (Correct Answer)
Explanation: **Flexor pollicis longus (FPL)** - The **FPL** is located in the **deep anterior compartment** of the forearm, differentiating it from the superficial muscles [1]. - Its primary function is **flexion of the thumb's interphalangeal joint**, requiring a deeper anatomical position for mechanical advantage [1]. *FDS* - The **Flexor digitorum superficialis (FDS)** is a key muscle of the superficial anterior compartment, visible just beneath the skin and fascia. - It is responsible for **flexing the middle phalanges** of the medial four digits. *FCR* - The **Flexor carpi radialis (FCR)** is situated in the superficial anterior compartment, running obliquely across the forearm. - It functions in **flexion and abduction of the wrist**. *Palmaris longus* - The **Palmaris longus** is a superficial anterior compartment muscle, though it is absent in a significant portion of the population. - When present, its main action is **flexion of the wrist** and tightening of the palmar aponeurosis.
Question 63: Which of the following structures is not found in the midpalmar space?
- A. 2nd lumbrical
- B. 1st lumbrical (Correct Answer)
- C. FDP of 4th finger
- D. FDP of 3rd finger
Explanation: ***1st lumbrical*** - The **1st lumbrical** is typically found within the **thenar space** or the **central compartment of the palm**, not the midpalmar space [1]. - Its position is associated with the **index finger's flexor tendons**, which do not traverse the midpalmar space. *2nd lumbrical* - The **2nd lumbrical** is located in the **midpalmar space**, situated on the radial side of the **flexor digitorum profundus (FDP) tendon** to the third digit [1]. - It arises from the radial side of the **FDP tendon** of the **middle finger** [1]. *FDP of 3rd finger* - The **flexor digitorum profundus (FDP) tendon** to the **third finger** (middle finger) passes through the **midpalmar space** [1]. - These tendons, along with their associated lumbricals, are key components of the **midpalmar space**. *FDP of 4th finger* - The **flexor digitorum profundus (FDP) tendon** to the **fourth finger** (ring finger) also travels through the **midpalmar space** [1]. - The midpalmar space contains the **FDP tendons** for the middle, ring, and little fingers, as well as their corresponding lumbricals (2nd, 3rd, and 4th).
Question 64: Axillary nerve is accompanied by which artery ?
- A. Posterior circumflex humeral artery (Correct Answer)
- B. Axillary artery
- C. Subscapular artery
- D. Anterior circumflex humeral artery
Explanation: ***Posterior circumflex humeral artery*** - The **axillary nerve** and the **posterior circumflex humeral artery** both pass through the **quadrangular space** in the axilla. - This anatomical relationship makes them vulnerable to injury together, particularly in cases of **shoulder dislocation** or **fractures of the surgical neck of the humerus**. *Axillary artery* - The **axillary artery** is the main arterial trunk of the axilla, but the axillary nerve is not typically described as directly accompanying the main trunk. - While branches of the axillary artery do supply the region where the axillary nerve travels, the specific artery that accompanies the nerve is a direct branch. *Subscapular artery* - The **subscapular artery** is the largest branch of the axillary artery and gives rise to the circumflex scapular and thoracodorsal arteries. - It does not directly accompany the axillary nerve through the quadrangular space; instead, it mostly supplies muscles like the **subscapularis** and **latissimus dorsi**. *Anterior circumflex humeral artery* - The **anterior circumflex humeral artery** also branches from the axillary artery and wraps around the surgical neck of the humerus. - However, it typically runs anteriorly and does not accompany the axillary nerve as it emerges from the quadrangular space posteriorly.
Question 65: 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 66: 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 67: 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 68: Interosseous membrane of forearm is pierced by?
- A. Brachial artery
- B. Anterior interosseous artery (Correct Answer)
- C. Posterior interosseous artery
- D. Ulnar recurrent artery
Explanation: ***Anterior interosseous artery*** - The **anterior interosseous artery** pierces the **interosseous membrane** in the **distal forearm** (approximately 5 cm above the wrist) to anastomose with the **posterior interosseous artery** and contribute to the **palmar carpal arch**. - This artery arises from the **common interosseous artery**, a branch of the **ulnar artery**. - This is the **classically taught structure** that pierces the interosseous membrane and is the standard answer in examination contexts. *Brachial artery* - The **brachial artery** is the main artery of the arm and terminates in the **cubital fossa** by dividing into the **radial** and **ulnar arteries**. - It does not pierce the **interosseous membrane** of the forearm as it is located in the arm, not the forearm. *Posterior interosseous artery* - The **posterior interosseous artery** arises from the **common interosseous artery** and passes **posteriorly between the oblique cord and the upper border of the interosseous membrane** to enter the posterior compartment of the forearm. - While it may pierce the membrane distally to anastomose anteriorly, the **anterior interosseous artery** is the structure **classically described** as piercing the membrane in standard anatomical teaching and examination contexts. *Ulnar recurrent artery* - The **ulnar recurrent arteries** (anterior and posterior branches) arise from the **ulnar artery** near the **cubital fossa** and ascend to participate in the **anastomosis around the elbow joint**. - These arteries do not pierce the **interosseous membrane** of the forearm.
Question 69: 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 70: Which muscles are known as 'Triceps surae'?
- A. Popliteus
- B. Extensor hallucis longus
- C. Extensor digitorum longus
- D. Gastro-soleus (Correct Answer)
Explanation: ***Gastro-soleus*** - The **Triceps surae** refers to the two heads of the **gastrocnemius muscle** and the **soleus muscle**, which together form the powerful calf muscle. - These three muscles converge to form the **Achilles tendon** (calcaneal tendon) and are prime movers for **plantarflexion** of the ankle. *Popliteus* - The popliteus muscle is located behind the knee joint and acts to **unlock the knee** during flexion. - It does not contribute to the bulk of the calf and is not part of the Triceps surae group. *Extensor hallucis longus* - This muscle is located in the **anterior compartment** of the leg and is responsible for **dorsiflexion** of the ankle and extension of the great toe. - It is an antagonist to the Triceps surae, which primarily performs plantarflexion. *Extensor digitorum longus* - The extensor digitorum longus is also in the **anterior compartment** of the leg, responsible for **dorsiflexion** of the ankle and extension of the lateral four toes. - It is functionally opposite to the actions of the Triceps surae and in a different muscle compartment.