Upper Limb Practice Questions

Q: 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: Erb-Duchenne paralysis occurs by lesion to brachial plexus at the level of

C5-C6. ***C5-C6*** - **Erb-Duchenne paralysis**, also known as **Erb's palsy**, results from injury to the upper roots of the **brachial plexus**, specifically the **C5 and C6 nerve roots** [1]. - This lesion commonly occurs due to **traction** on the upper trunk of the brachial plexus during difficult childbirth or trauma, leading to characteristic "waiter's tip" posture [1]. *C8-T1* - A lesion at the **C8-T1** level of the brachial plexus causes **Klumpke's paralysis**, which affects the intrinsic muscles of the hand and causes a "claw hand" deformity. - This is distinct from Erb's palsy, which primarily affects shoulder and elbow movements. *C6-C7* - While C6 is involved in Erb's palsy, a lesion specifically at **C6-C7** would implicate the middle trunk and is not the primary site for the classic Erb-Duchenne paralysis. - Isolated C7 involvement would primarily affect wrist extensors and finger extensors, which are different from the clinical presentation of Erb's palsy. *C4-C5* - Injury to **C4-C5** would affect the phrenic nerve (C3-C5) and contribute to diaphragm dysfunction, as well as the upper trapezius and levator scapulae, but it is not the typical presentation or origin of Erb-Duchenne paralysis specifically. - C5 is part of Erb's palsy, but the defining lesion involves both C5 and C6, not just C4-C5.

Q: In a diving accident that severed the spinal cord below the sixth cervical vertebra, which of the following muscles would be affected?

Latissimus Dorsi. ***Latissimus Dorsi*** - The **latissimus dorsi muscle** is primarily innervated by the **thoracodorsal nerve**, which arises from the **C6, C7, and C8** nerve roots (with C7 and C8 being the predominant contributors) [1]. - A spinal cord injury below the sixth cervical vertebra would affect the C7 and C8 segments, thereby disrupting the nerve supply to the latissimus dorsi, leading to weakness or paralysis. - This muscle is responsible for adduction, extension, and internal rotation of the shoulder. *Deltoid* - The **deltoid muscle** is innervated by the **axillary nerve**, which arises predominantly from the **C5 and C6** nerve roots. - Since the injury is below the C6 vertebra, the upper cervical segments (C5 and C6) would remain intact above the level of injury. - Therefore, deltoid function would be preserved. *Infraspinatus* - The **infraspinatus muscle** is innervated by the **suprascapular nerve**, which arises from the **C5 and C6** nerve roots. - Similar to the deltoid, its innervation originates above the level of the spinal cord injury and would be spared. *Levator Scapulae* - The **levator scapulae muscle** receives innervation from the **C3, C4, and C5** spinal nerves, as well as contributions from the dorsal scapular nerve (predominantly C5). - All of these nerve roots originate well above the level of injury, so this muscle would not be affected.

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: In interphalangeal joint, the capsule is thinnest on the -

Dorsal side. ***Dorsal side*** - The interphalangeal joint capsule is thinnest on the **dorsal side** due to the need for flexibility during **flexion** and the presence of the **extensor tendon** covering this aspect. - This anatomical arrangement allows for a greater range of motion for finger flexion, as the dorsal capsule offers less resistance. *Palmar side* - The capsule on the palmar side is reinforced by the **volar plate** and accessory **collateral ligaments**, making it thicker and stronger to prevent hyperextension. - This thickening provides crucial stability to the joint during gripping and other hand functions. *Medial side* - The medial side of the interphalangeal joint capsule is reinforced by the **collateral ligament**, which provides significant stability against sideways forces. - This ligament helps prevent excessive abduction or adduction of the finger. *Lateral side* - Similar to the medial side, the lateral aspect of the joint capsule is strengthened by the **collateral ligament**. - This reinforcement is vital for maintaining joint integrity and preventing dislocation during lateral stresses.

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: Which muscle helps in climbing a tree?

Latissimus Dorsi. ***Latissimus Dorsi*** - The **latissimus dorsi** is a large, powerful muscle responsible for **adduction, extension, and internal rotation** of the shoulder joint, all actions crucial for pulling the body upward during climbing. [1] - Its broad attachment helps stabilize the torso and provides the necessary force for **pulling and gripping** movements involved in tree climbing. *Trapezius* - The **trapezius** primarily functions in **shrugging the shoulders**, retracting the scapula, and rotating the head and neck. - While it contributes to overall upper body strength, its main actions are not directly involved in the powerful **pulling motion** required for climbing. *Rhomboideus* - The **rhomboids (major and minor)** primarily act to **retract (pull back) and rotate the scapula** downwards. - These actions are important for stabilizing the shoulder blade but are not the primary movers for the **vertical pulling** associated with climbing. *Levator scapulae* - The **levator scapulae** elevates the scapula and can assist in rotating the neck. - While it contributes to shoulder girdle movement, it does not provide the significant **pulling force** needed to lift the body during climbing.

Question 1

An injury to the shown area can lead to fracture of which bone

Accepted Answer

Scaphoid

Answer

Lunate

Answer

Hamate

Answer

Trapezium

Question 2

Erb-Duchenne paralysis occurs by lesion to brachial plexus at the level of

Accepted Answer

C5-C6

Answer

C8-T1

Answer

C6-C7

Answer

C4-C5

Question 3

In a diving accident that severed the spinal cord below the sixth cervical vertebra, which of the following muscles would be affected?

Accepted Answer

Latissimus Dorsi

Answer

Deltoid

Answer

Infraspinatus

Answer

Levator Scapulae

Question 4

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 5

In interphalangeal joint, the capsule is thinnest on the -

Accepted Answer

Dorsal side

Answer

Palmar side

Answer

Medial side

Answer

Lateral side

Question 6

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 7

Partial claw hand is caused by lesion involving the:

Accepted Answer

Ulnar nerve

Answer

Anterior interosseous nerve

Answer

Radial nerve

Answer

Median nerve

Question 8

In cubital fossa, which structure is the most medial

Accepted Answer

Median nerve

Answer

Brachial artery

Answer

Radial nerve

Answer

Biceps tendon

Question 9

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 10

Which muscle helps in climbing a tree?

Accepted Answer

Latissimus Dorsi

Answer

Trapezius

Answer

Rhomboideus

Answer

Levator scapulae

Upper Limb — MCQs

Upper Limb — MCQs

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