Upper Limb Practice Questions

Q: Retraction of scapula is done by

Trapezius. ***Trapezius*** - The **trapezius** muscle, particularly the middle fibers, is responsible for **retracting the scapula**, pulling it medially towards the vertebral column. - This action is crucial for stabilizing the shoulder girdle and enabling various arm movements. *Serratus anterior* - The **serratus anterior** is primarily responsible for **protraction of the scapula** (pulling it forward) and stabilizing it against the thoracic wall. - It also aids in upward rotation of the scapula. *Supraspinatus* - The **supraspinatus** muscle is a rotator cuff muscle involved in the **initiation of arm abduction** (lifting the arm away from the body). - It does not directly contribute to scapular retraction. *Subscapularis* - The **subscapularis** is another rotator cuff muscle, primarily responsible for **internal rotation of the arm** and stabilization of the glenohumeral joint. - It has no direct role in scapular retraction.

Q: A patient presents with tenderness over the anatomical snuffbox after a fall on an outstretched hand. An injury to the shown area can lead to fracture of which bone

Scaphoid. ***Scaphoid*** - An injury to the **anatomical snuffbox** is a classic presentation for a **scaphoid fracture**. - This bone is particularly vulnerable due to its **limited blood supply**, which can lead to complications such as **avascular necrosis** if untreated. *Lunate* - The lunate is more commonly associated with **dislocations** or **Kienbock's disease** (avascular necrosis of the lunate), rather than fracture from isolated anatomical snuffbox injury. - Pain from a lunate injury often presents more volarly or centrally within the wrist, not specifically the snuffbox. *Hamate* - Fractures of the **hamate** typically occur from direct trauma to the hypothenar eminence, such as from hitting a golf club or tennis racket. - This mechanism of injury and location of pain are distinct from an anatomical snuffbox injury. *Trapezium* - The **trapezium** is more commonly fractured in association with **Bennett's fracture** (fracture at the base of the thumb metacarpal) or from direct trauma to the thumb. - Pain from a trapezium fracture is usually localized to the base of the thumb, rather than the radial aspect of the wrist.

Q: Extensor carpi radialis longus is

Extensor and radial deviator of the wrist. ***Extensor and radial deviator of the wrist*** - The **extensor carpi radialis longus (ECRL)** is one of the primary muscles responsible for **extension of the wrist**. [1] - Due to its anatomical position on the radial side of the forearm, it also contributes significantly to **radial deviation** (abduction) of the wrist. [1] *Weak extensor of the wrist* - While it is an extensor, the ECRL is considered a **strong extensor** of the wrist, especially when acting with other extensors like the Extensor Carpi Radialis Brevis (ECRB). [1] - Its strength is crucial for tasks requiring **grip and wrist stabilization**. *Extensor and ulnar deviator of the wrist* - The ECRL performs wrist extension but causes **radial deviation**, not ulnar deviation. [1] - **Ulnar deviation** is primarily performed by the **extensor carpi ulnaris** and **flexor carpi ulnaris**. *Injured in Posterior interosseous nerve injury* - The ECRL is innervated by the **radial nerve** **before** it divides into the superficial and deep (posterior interosseous) branches. [2] - Therefore, ECRL function is typically **spared in isolated posterior interosseous nerve injuries**, which mainly affect muscles in the deep compartment of the posterior forearm. [2]

Q: Test shown in the video is for which structure & its nerve supply:

Supraspinatus C5,C6. ***Supraspinatus C5,C6*** - The **supraspinatus muscle** is responsible for the initiation of shoulder abduction. The video likely depicts a test for this muscle. - Its nerve supply is from the **suprascapular nerve**, which originates from the **C5 and C6 nerve roots**. *Teres minor C5,C6* - The **teres minor** aids in **external rotation** of the shoulder, not abduction, and is tested through different movements. - It is innervated by the **axillary nerve**, which receives fibers from **C5 and C6**. *Infraspinatus C5,C6* - The **infraspinatus muscle** is a primary **external rotator** of the shoulder, not an abductor. - Its nerve supply is from the **suprascapular nerve**, primarily from **C5 and C6**. *Subscapularis C5,C6* - The **subscapularis muscle** is responsible for **internal rotation** of the shoulder and is tested with different specific maneuvers. - It receives its innervation from the **upper and lower subscapular nerves**, which arise from the **C5 and C6 roots**.

Q: Partial claw hand is caused by lesion involving the:

Ulnar nerve. ***Ulnar nerve*** - A lesion of the **ulnar nerve** causes a **partial claw hand** (also called "ulnar claw") because the **medial two lumbricals** (which flex the MCP joints and extend the IP joints of the 4th and 5th digits) and the **interossei** are paralyzed [1]. - This leads to hyperextension at the **metacarpophalangeal (MCP) joints** and flexion at the **interphalangeal (IP) joints** of the **4th and 5th fingers only** (hence "partial") [1]. - The lateral two fingers (index and middle) are spared because their lumbricals are supplied by the median nerve [1]. *Anterior interosseous nerve* - Injury to the **anterior interosseous nerve** primarily affects the **flexor pollicis longus**, **flexor digitorum profundus** (index and middle fingers), and **pronator quadratus**. - This results in the inability to make an "OK" sign (pinch sign) and does not typically cause a claw hand deformity. *Radial nerve* - A **radial nerve** lesion leads to **wrist drop** and the inability to extend the wrist and fingers. - This deformity is distinct from a claw hand, which involves hyperextension at the MCP joints and flexion at the IP joints. *Median nerve* - A **median nerve** lesion results in a "hand of benediction" or "ape hand" deformity, affecting the **thenar muscles** and the **lateral two lumbricals** [1]. - This involves paralysis of the thumb's opposition and the inability to flex the index and middle fingers, not the characteristic clawing of the 4th and 5th digits.

Q: In cubital fossa, which structure is the most medial

Median nerve. ***Median nerve*** - The **median nerve** is the most medial structure within the cubital fossa, positioned medial to the brachial artery. - Its medial position is crucial for understanding its vulnerability to injury in this region, especially during venipuncture or supracondylar fractures of the humerus. - It runs along the medial border of the brachial artery throughout its course in the cubital fossa. *Brachial artery* - The **brachial artery** lies lateral to the median nerve and medial to the biceps tendon in the cubital fossa. - It is a major vessel used for blood pressure measurement and is a common site for arterial punctures. - It bifurcates into radial and ulnar arteries at the level of the radial neck. *Radial nerve* - The **radial nerve** is the most lateral structure in the cubital fossa, positioned deep to the brachioradialis muscle. - It divides into deep (posterior interosseous) and superficial branches just distal to the lateral epicondyle. - The deep branch is at risk during surgical approaches to the radial head. *Biceps tendon* - The **biceps tendon** is located centrally within the cubital fossa, lying lateral to the brachial artery. - It inserts into the radial tuberosity and is an important landmark for palpation in the fossa. - The bicipital aponeurosis (lacertus fibrosus) arises from its medial side and protects the median nerve and brachial artery.

Q: Which of the following will not take place in a patient with ulnar nerve injury in arm?

Weakness of flexor digitorum profundus to index finger. ***Weakness of flexor digitorum profundus to index finger*** - The **flexor digitorum profundus** muscle has dual innervation: the ulnar half (to the ring and little fingers) is supplied by the ulnar nerve, but the radial half (to the index and middle fingers) is supplied by the **median nerve**. - Therefore, an ulnar nerve injury would not affect the function of the flexor digitorum profundus to the index finger. *Claw hand* - A low ulnar nerve injury (at the wrist) typically results in **ulnar claw hand**, where the 4th and 5th digits are hyperextended at the MCP joints and flexed at the IP joints. - This is due to paralysis of the **lumbricals** to the 4th and 5th digits, leading to unopposed action of the extensor digitorum and flexor digitorum profundus. *Weakness of flexor carpi ulnaris* - The **flexor carpi ulnaris** is innervated exclusively by the ulnar nerve. - An ulnar nerve injury in the arm would therefore lead to weakness or paralysis of this muscle, affecting wrist flexion and ulnar deviation. *Sensory loss over medial aspect of hand* - The ulnar nerve provides sensory innervation to the **medial 1 and 1/2 fingers** (little finger and medial half of the ring finger) as well as the corresponding palmar and dorsal aspects of the hand. - An ulnar nerve injury would result in sensory deficits in this distribution.

Q: What is the MOST characteristic feature of low ulnar nerve palsy? a) Claw hand b) Sensory loss of medial four digits c) Weakness of grip d) Inability to abduct the thumb

Claw hand. ***Claw hand*** - A **claw hand** (specifically an **ulnar claw**) is a classic sign of low ulnar nerve palsy, resulting from paralysis of the **interossei** and **medial two lumbricals**. - This leads to hyperextension at the **metacarpophalangeal (MCP) joints** and flexion at the **interphalangeal (IP) joints** of the 4th and 5th digits. *Sensory loss of lateral three digits* - Sensory loss in the **lateral three digits** (thumb, index, middle fingers) is characteristic of **median nerve palsy**, not ulnar nerve palsy. - The ulnar nerve supplies sensation to the **medial 1.5 digits** (half of the ring finger and the little finger). *Weakness of wrist flexion* - While the ulnar nerve contributes to wrist flexion via the **flexor carpi ulnaris**, significant weakness in overall wrist flexion alone is not its most characteristic distinguishing feature. - The median nerve and radial nerve also play crucial roles in wrist flexion and extension, respectively. *Inability to oppose the thumb* - The inability to **oppose the thumb** (touch the thumb to the tips of the other fingers) is a hallmark of **median nerve palsy**, specifically affecting the **opponens pollicis** muscle. - The ulnar nerve primarily affects adduction of the thumb via the **adductor pollicis**. *Inability to extend at M.C.P. joint* - The inability to extend at the **metacarpophalangeal (MCP) joint** is more characteristic of **radial nerve palsy**, which affects the **extensor muscles** of the fingers. - Ulnar nerve palsy causes increased extension at the MCP joints due to paralysis of the lumbricals and interossei.

Q: A patient presents with winging of the scapula. Which nerve is most likely involved?

Long thoracic nerve. ### Long thoracic nerve - The long thoracic nerve innervates the **serratus anterior muscle**, which is responsible for scapular protraction and upward rotation. - Damage to this nerve paralyzes the serratus anterior, leading to **winging of the scapula** as the medial border and inferior angle of the scapula become prominent. ### Thoracodorsal nerve - This nerve supplies the **latissimus dorsi muscle**, which is involved in adduction, extension, and internal rotation of the humerus [1]. - Injury to the thoracodorsal nerve would weaken movements of the shoulder, but not directly cause **scapular winging**. ### Lateral pectoral nerve - The lateral pectoral nerve innervates the **pectoralis major muscle** (upper and middle parts) [1]. - Damage to this nerve primarily affects shoulder adduction and internal rotation, but does not result in **scapular winging**. ### Musculocutaneous nerve - This nerve innervates the **coracobrachialis**, **biceps brachii**, and **brachialis muscles** in the anterior compartment of the arm. - Injury to the musculocutaneous nerve would impair elbow flexion and forearm supination, and is unrelated to **scapular movement**.

Q: Strongest supinator muscle is -

Biceps. ***Biceps*** - The **biceps brachii** is the most powerful supinator of the forearm, especially when the elbow is flexed at 90 degrees. - Its long lever arm and direct attachment to the **radial tuberosity** give it significant mechanical advantage for supination. *Brachialis* - The **brachialis** is the primary flexor of the elbow joint and plays a minimal role in forearm supination. - Its insertion on the **ulna** means it has no direct action on the rotation of the radius. *Supinator* - The **supinator muscle** is a primary supinator of the forearm, particularly when the elbow is extended or during slow, unresisted supination. - However, it is less powerful than the biceps brachii, especially against resistance or with the elbow flexed. *Brachioradialis* - The **brachioradialis** is primarily a flexor of the elbow, particularly active during rapid movements or against resistance. - Its main action is to bring the forearm to a neutral position between pronation and supination, not to strongly supinate.

Question 1

Retraction of scapula is done by

Accepted Answer

Trapezius

Answer

Serratus anterior

Answer

Supraspinatus

Answer

Subscapularis

Question 2

A patient presents with tenderness over the anatomical snuffbox after a fall on an outstretched hand. An injury to the shown area can lead to fracture of which bone

Accepted Answer

Scaphoid

Answer

Trapezium

Answer

Lunate

Answer

Hamate

Question 3

Extensor carpi radialis longus is

Accepted Answer

Extensor and radial deviator of the wrist

Answer

Weak extensor of the wrist

Answer

Extensor and ulnar deviator of the wrist

Answer

Injured in Posterior interosseous nerve injury

Question 4

Test shown in the video is for which structure & its nerve supply:

Accepted Answer

Supraspinatus C5,C6

Answer

Teres minor C5,C6

Answer

Infraspinatus C5,C6

Answer

Subscapularis C5,C6

Question 5

Partial claw hand is caused by lesion involving the:

Accepted Answer

Ulnar nerve

Answer

Anterior interosseous nerve

Answer

Radial nerve

Answer

Median nerve

Question 6

In cubital fossa, which structure is the most medial

Accepted Answer

Median nerve

Answer

Brachial artery

Answer

Radial nerve

Answer

Biceps tendon

Question 7

Which of the following will not take place in a patient with ulnar nerve injury in arm?

Accepted Answer

Weakness of flexor digitorum profundus to index finger

Answer

Claw hand

Answer

Weakness of flexor carpi ulnaris

Answer

Sensory loss over medial aspect of hand

Question 8

What is the MOST characteristic feature of low ulnar nerve palsy? a) Claw hand b) Sensory loss of medial four digits c) Weakness of grip d) Inability to abduct the thumb

Accepted Answer

Claw hand

Answer

Sensory loss of lateral three digits

Answer

Weakness of wrist flexion

Answer

Inability to oppose the thumb

Answer

Inability to extend at M.C.P. joint

Question 9

A patient presents with winging of the scapula. Which nerve is most likely involved?

Accepted Answer

Long thoracic nerve

Answer

Thoracodorsal nerve

Answer

Lateral pectoral nerve

Answer

Musculocutaneous nerve

Question 10

Strongest supinator muscle is -

Accepted Answer

Biceps

Answer

Brachialis

Answer

Supinator

Answer

Brachioradialis

Upper Limb — MCQs

Upper Limb — MCQs

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