Upper Limb Practice Questions

Q: Which nerve supplies the area marked as ‘Area B’ in the image?

Radial nerve. ***Radial nerve*** - The radial nerve provides **sensory innervation to the dorsum of the hand**, specifically the radial side including the dorsal aspect of the **thumb, index, middle, and radial half of the ring finger** (excluding the distal phalanges) - This anatomical snuffbox region and dorsal hand area is the characteristic **sensory distribution of the superficial branch of the radial nerve** - The radial nerve also provides **motor innervation to extensor muscles of the forearm** via its posterior interosseous branch *Ulnar nerve* - Supplies sensory innervation to the **ulnar 1.5 digits** (little finger and ulnar half of ring finger) on both palmar and dorsal surfaces - Provides motor innervation to **most intrinsic hand muscles** (hypothenar muscles, interossei, medial lumbricals) - Would not innervate a radial-sided area on the dorsum of the hand *Median nerve* - Provides sensory innervation primarily to the **palmar surface** of the lateral 3.5 digits (thumb, index, middle, and radial half of ring finger) - On the dorsum, only supplies the **distal phalanges (nail beds)** of index and middle fingers - Supplies motor innervation to **thenar muscles** and lateral lumbricals - Does not provide primary sensory innervation to broad dorsal hand areas *Posterior interosseous nerve* - This is the **deep motor branch of the radial nerve** that passes through the supinator muscle - Provides **motor innervation** to extensor muscles in the posterior forearm compartment - Has minimal sensory function, limited to **proprioceptive innervation of wrist joint capsule** - Does not provide cutaneous sensory innervation to skin areas

Q: Which nerve supplies the rhomboid major and minor muscles?

Dorsal scapular nerve. Dorsal scapular nerve - The **dorsal scapular nerve** directly innervates the **rhomboid major** and **rhomboid minor** muscles, as well as the **levator scapulae** muscle. - This nerve originates from the C5 root of the brachial plexus. *Thoracodorsal nerve* - The **thoracodorsal nerve** primarily innervates the **latissimus dorsi** muscle, which is involved in adduction, extension, and internal rotation of the humerus [1]. - This nerve arises from the posterior cord of the brachial plexus. *Spinal accessory nerve* - The **spinal accessory nerve (CN XI)** is responsible for innervating the **sternocleidomastoid** and **trapezius** muscles. - It plays a crucial role in neck movement and shoulder elevation. *Suprascapular nerve* - The **suprascapular nerve** supplies the **supraspinatus** and **infraspinatus** muscles, which are part of the rotator cuff. - Damage to this nerve can impair shoulder abduction and external rotation.

Q: Identify the marked muscle in the diagram.

Flexor carpi ulnaris. ***Flexor carpi ulnaris*** - This muscle originates via two heads: the **humeral head** from the **medial epicondyle of the humerus** and the **ulnar head** from the **olecranon and posterior border of the ulna**. - It inserts into the **pisiform**, **hook of hamate**, and **base of the 5th metacarpal**. - It is located in the **anterior compartment of the forearm**, on the ulnar (medial) side, forming the medial border of the forearm. - Its primary actions are **flexion** and **adduction (ulnar deviation)** of the wrist. *Brachialis* - The **brachialis** muscle is located in the **anterior compartment of the upper arm**, deep to the biceps brachii. - Its primary function is **flexion of the elbow joint**, entirely different from the marked forearm muscle. *Extensor carpi radialis brevis* - The **extensor carpi radialis brevis** originates from the **lateral epicondyle of the humerus** and inserts onto the base of the **3rd metacarpal**. - It is located on the **posterior forearm** and acts as a primary extensor and abductor of the wrist, clearly distinct from the anterior ulnar location shown. *Extensor digitorum* - The **extensor digitorum** primarily extends the medial four fingers, originating from the lateral epicondyle and inserting into the extensor expansions of the digits. - It is located in the **posterior forearm**, distinguishing it from the anterior medial muscle marked in the diagram.

Q: What is the nerve supply of the structure marked in the image?

Ulnar nerve. ***Ulnar nerve*** - The image points to a **hypothenar muscle**. The **ulnar nerve** innervates the hypothenar muscles, which include the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi. - These muscles contribute to movements of the **little finger**, including abduction, flexion, and opposition. *Anterior interosseous nerve* - The anterior interosseous nerve is a branch of the **median nerve** and primarily supplies deep muscles of the forearm, such as the **flexor pollicis longus**, **flexor digitorum profundus (lateral half),** and **pronator quadratus**. - It does not directly innervate the hypothenar muscles in the hand. *Posterior interosseous nerve* - The posterior interosseous nerve is a branch of the **radial nerve**. - It primarily innervates the **extensor muscles of the forearm** and wrist, not the hypothenar muscles. *Median nerve* - The **median nerve** innervates the **thenar muscles** (abductor pollicis brevis, opponens pollicis, and the superficial head of flexor pollicis brevis) and the lateral two lumbricals. Note that the deep head of flexor pollicis brevis commonly receives ulnar innervation. - It does not supply the hypothenar muscles, which are supplied by the ulnar nerve.

Q: Identify the anatomical structures visible in the image.

Styloid process of the ulna. ***Styloid process of the ulna*** - The styloid process of the ulna is a **pointed projection** of bone located on the **medial side of the distal ulna**. - It serves as an **attachment point** for the ulnar collateral ligament and the apex of the triangular fibrocartilage complex (TFCC), and it contributes to **medial wrist and distal radioulnar joint stability**. *Extensor pollicis longus and Abductor pollicis longus* - The **extensor pollicis longus** forms the **ulnar border of the anatomical snuffbox**, while the **abductor pollicis longus** forms the **radial border**. - While these **tendons are located in the vicinity**, the image specifically highlights the **bony landmark** of the ulnar styloid. *Styloid process of the radius* - The **styloid process of the radius** is located on the **lateral aspect of the distal radius**. - It is **longer and more prominent** than the ulnar styloid process, and the image clearly points to the **medial distal forearm prominence**. *Scaphoid bone* - The **scaphoid bone** is one of the **carpal bones** located in the proximal row of the wrist. - It lies **distal to the radius** and is a common site for fractures, but the pointer in the image is clearly indicating a **distal forearm bony projection**, not a carpal bone.

Q: Low radial nerve palsy (just after the spiral groove) does not produce which of the following?

Loss of elbow extension. ***Loss of elbow extension*** - A low radial nerve palsy, occurring **distal to the spiral groove**, affects branches supplying the forearm and hand. - The nerves to the **triceps brachii**, responsible for elbow extension, branch off **proximal to the spiral groove**. *Loss of wrist extension* - The muscles responsible for **wrist extension** (e.g., extensor carpi radialis longus, brevis, and extensor carpi ulnaris) are innervated by the radial nerve or its deep branch **distal to the spiral groove**. - Therefore, a low radial nerve palsy would cause **loss of wrist extension**, leading to **wrist drop**. *Loss of finger extension* - The **extensor digitorum**, **extensor indicis**, and **extensor digiti minimi** muscles, which extend the fingers, are innervated by the posterior interosseous nerve (a continuation of the deep radial nerve) also **distal to the spiral groove**. - A low radial nerve palsy would result in the inability to **extend the fingers**. *Loss of thumb extension* - The muscles involved in **thumb extension** (e.g., abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) are also supplied by the posterior interosseous nerve, originating **distal to the spiral groove**. - Consequently, **loss of thumb extension** would be a feature of a low radial nerve palsy.

Q: Which of the following arteries contributes MOST to the deep palmar arch?

Radial artery. ***Radial artery*** - The **radial artery** is the primary contributor to the **deep palmar arch**, giving off the **princeps pollicis artery** and the **radialis indicis artery** before continuing as the main part of the arch. - It anastomoses with the deep branch of the ulnar artery to complete the arch. *Ulnar artery* - The **deep branch of the ulnar artery** contributes to the deep palmar arch, but it is a smaller, anastomotic component rather than the primary contributor itself. - The ulnar artery is the primary contributor to the **superficial palmar arch**. *Posterior interosseous artery* - The **posterior interosseous artery** supplies muscles in the posterior compartment of the forearm and does not directly contribute to the deep palmar arch. - It arises from the common interosseous artery and terminates in the wrist region, supplying the dorsal carpal network. *Anterior interosseous artery* - The **anterior interosseous artery** supplies muscles of the deep anterior forearm compartment and gives off branches to the wrist but does not directly form the deep palmar arch. - It also contributes to the **palmar carpal arch** but not the deep palmar arch.

Q: Pulp of the index finger is supplied by

Median nerve. ***Median nerve*** - The **median nerve** innervates the **radial side of the hand**, including the palmar surface of the thumb, index finger, middle finger, and the radial half of the ring finger [1]. - Sensation to the **pulp of the index finger** is specifically provided by the **median nerve** [1]. *Radial nerve* - The **radial nerve** primarily supplies the **dorsum of the hand** and fingers, except for the distal phalanges. - It does not provide sensory innervation to the palmar surface or pulp of the index finger. *Ulnar nerve* - The **ulnar nerve** innervates the **ulnar side of the hand**, specifically the palmar and dorsal surfaces of the little finger and the ulnar half of the ring finger [1]. - It plays no role in the sensation of the index finger pulp. *Axillary nerve* - The **axillary nerve** innervates the **deltoid muscle** and provides sensation to the skin over the deltoid region, often referred to as the "regimental badge area." - It is located in the shoulder region and has no sensory distribution in the hand.

Q: What type of muscles are medial two lumbricals?

Bipennate. ***Bipennate*** - The **medial two lumbricals** (third and fourth) are classified as **bipennate muscles** because they originate from two adjacent tendons of the flexor digitorum profundus (FDP). - Each of these lumbricals arises from the **adjacent sides of two FDP tendons**, with muscle fibers converging toward a central insertion, creating a bipennate arrangement. - This dual origin distinguishes them from the lateral two lumbricals, which are unipennate. *Unipennate* - **Unipennate muscles** have fibers that attach obliquely to only one side of a single tendon. - The **lateral two lumbricals** (first and second) are unipennate as they each arise from a single FDP tendon. - This is not the correct classification for the medial two lumbricals. *Multipennate* - **Multipennate muscles** have multiple tendon arrangements with fibers converging at different angles from several directions. - Examples include the **deltoid muscle**, which has a much more complex architecture than lumbricals. *None of the options* - Since **bipennate** accurately describes the structure of the medial two lumbricals based on their dual tendon origins, this option is incorrect. - The architectural classification is well-established in anatomical literature.

Q: Which muscle acting on the thumb is the only one among the options that has dual nerve supply?

Flexor Pollicis Brevis. ***Flexor Pollicis Brevis (FPB)*** - The **Flexor Pollicis Brevis** is unique among thumb muscles because it commonly has a **dual nerve supply**. [1] - Its superficial head is innervated by the **median nerve**, while its deep head is innervated by the **ulnar nerve**. *Flexor Pollicis Longus (FPL)* - The **Flexor Pollicis Longus** is solely innervated by the **anterior interosseous nerve**, a branch of the **median nerve**. [1] - It does not receive any neural input from the ulnar nerve. *Adductor Pollicis* - The **Adductor Pollicis** muscle is exclusively innervated by the **deep branch of the ulnar nerve**. - It plays a crucial role in **adduction of the thumb** and does not share innervation with the median nerve. *Opponens Pollicis* - The **Opponens Pollicis** is primarily supplied by the **recurrent branch of the median nerve** (also known as the thenar motor branch). - Its function is **opposition of the thumb**, and it does not have dual innervation.

Question 1

Which nerve supplies the area marked as ‘Area B’ in the image?

Accepted Answer

Radial nerve

Answer

Ulnar nerve

Answer

Median nerve

Answer

Posterior interosseous nerve

Question 2

Which nerve supplies the rhomboid major and minor muscles?

Accepted Answer

Dorsal scapular nerve

Answer

Thoracodorsal nerve

Answer

Spinal accessory nerve

Answer

Suprascapular nerve

Question 3

Identify the marked muscle in the diagram.

Accepted Answer

Flexor carpi ulnaris

Answer

Brachialis

Answer

Extensor carpi radialis brevis

Answer

Extensor digitorum

Question 4

What is the nerve supply of the structure marked in the image?

Accepted Answer

Ulnar nerve

Answer

Anterior interosseous nerve

Answer

Posterior interosseous nerve

Answer

Median nerve

Question 5

Identify the anatomical structures visible in the image.

Accepted Answer

Styloid process of the ulna

Answer

Extensor pollicis longus and Abductor pollicis longus

Answer

Scaphoid bone

Answer

Styloid process of the radius

Question 6

Low radial nerve palsy (just after the spiral groove) does not produce which of the following?

Accepted Answer

Loss of elbow extension

Answer

Loss of finger extension

Answer

Loss of wrist extension

Answer

Loss of thumb extension

Question 7

Which of the following arteries contributes MOST to the deep palmar arch?

Accepted Answer

Radial artery

Answer

Ulnar artery

Answer

Posterior interosseous artery

Answer

Anterior interosseous artery

Question 8

Pulp of the index finger is supplied by

Accepted Answer

Median nerve

Answer

Radial nerve

Answer

Ulnar nerve

Answer

Axillary nerve

Question 9

What type of muscles are medial two lumbricals?

Accepted Answer

Bipennate

Answer

Multipennate

Answer

None of the options

Answer

Unipennate

Question 10

Which muscle acting on the thumb is the only one among the options that has dual nerve supply?

Accepted Answer

Flexor Pollicis Brevis

Answer

Flexor Pollicis Longus

Answer

Adductor Pollicis

Answer

Opponens Pollicis

Upper Limb — MCQs

Upper Limb — MCQs

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