Upper Limb Practice Questions

Q: Boundaries of quadrilateral space include all EXCEPT:

Deltoid. ***Deltoid*** - The **deltoid muscle** overlies the shoulder joint and does not form a boundary for the quadrilateral space. - Its primary actions are **abduction**, flexion, and extension of the arm, but it is not directly involved in defining this specific anatomical passageway. *Teres major* - The **teres major muscle** forms the inferior border of the quadrilateral space. - It separates the quadrilateral space from the lower triangular space. *Long head of triceps* - The **long head of the triceps brachii muscle** forms the medial border of the quadrilateral space. - It also separates the quadrilateral space from the upper triangular space. *Neck of humerus* - The **surgical neck of the humerus** forms the lateral boundary of the quadrilateral space. - The **axillary nerve** and **posterior circumflex humeral artery** pass through this space, wrapping around the surgical neck of the humerus.

Q: Skin over hypothenar eminence is supplied by?

Ulnar nerve. ***Ulnar nerve*** - The **hypothenar eminence** and the medial side of the palm are innervated by the **ulnar nerve** for sensory input [1]. - The **superficial branch of the ulnar nerve** provides sensory innervation to this region [1]. *Radial nerve* - The **radial nerve** primarily supplies the dorsum of the hand and the lateral aspect of the forearm. - It does not innervate the **hypothenar eminence**. *Median nerve* - The **median nerve** innervates the lateral palm, thumb, index, middle, and radial half of the ring finger [1]. - It does not provide sensation to the **hypothenar eminence**. *Anterior interosseous nerve* - The **anterior interosseous nerve** is a branch of the median nerve and is purely motor. - It supplies deep muscles in the forearm and has **no sensory innervation** to the hand.

Q: Which nerves primarily supply the small muscles of the hand?

Ulnar and Median Nerves. The ulnar nerve innervates most intrinsic hand muscles, including the hypothenar muscles, interossei, and the medial two lumbricals [1]. The median nerve innervates the thenar muscles (excluding adductor pollicis), and the lateral two lumbricals, essential for fine motor skills [1]. While the radial nerve provides sensory innervation to part of the hand, its motor supply to intrinsic hand muscles is minimal [2].

Q: Which muscle primarily forms the posterior wall of the axilla?

Subscapularis. ***Subscapularis*** - The **subscapularis** muscle forms the **largest and superior part of the posterior wall of the axilla**. - It arises from the subscapular fossa on the anterior surface of the scapula and its broad surface creates the majority of the posterior axillary wall. - It is a key component of the rotator cuff and passes through the axilla to insert on the lesser tubercle of the humerus. *Latissimus dorsi* - The **latissimus dorsi** contributes to the **inferior part of the posterior wall** of the axilla [1]. - Along with teres major, it forms the lower border of the posterior wall, but does not form the primary or largest component [1]. *Teres major* - The **teres major** also forms part of the **inferior portion of the posterior wall**, lying superior to latissimus dorsi. - Together with latissimus dorsi, it contributes to the lower aspect of the posterior wall. *Pectoralis major* - The **pectoralis major** forms the **anterior wall of the axilla**, not the posterior wall [1]. - It is a large, fan-shaped muscle essential for adduction and medial rotation of the humerus [1].

Q: Which structure is described as intracapsular but extrasynovial in the shoulder joint?

Long head of biceps. ***Long head of biceps*** - The tendon of the **long head of the biceps brachii muscle** runs through the **capsule of the shoulder joint** to attach to the supraglenoid tubercle. - While it is located within the joint capsule (intracapsular), it is **surrounded by a synovial sheath** (an invagination of the synovial membrane that separates it from the main joint cavity), classifying it as **extrasynovial**. - This means the tendon passes through the joint but is not directly bathed in the synovial fluid of the main joint space. *Long head of triceps* - The **long head of the triceps brachii** originates from the **infraglenoid tubercle** of the scapula, which is **extra-articular** relative to the shoulder joint. - Therefore, it is neither intracapsular nor extrasynovial within the shoulder joint. *Short head of biceps* - The **short head of the biceps brachii** originates from the **coracoid process** of the scapula. - This origin is located **outside the shoulder joint capsule**, making it a completely extra-articular structure. *Coracobrachialis* - The **coracobrachialis muscle** originates from the **coracoid process** of the scapula. - This origin is also **outside the shoulder joint capsule**, placing it entirely extra-articular.

Q: Identify the muscles responsible for scapular retraction and elevation. What is their nerve supply?

Rhomboids and Levator Scapulae - Dorsal scapular nerve. ***Rhomboids and Levator Scapulae - Dorsal scapular nerve*** - The **rhomboid major** and **rhomboid minor** muscles are primarily responsible for **scapular retraction** (pulling the scapula towards the spine). - The **levator scapulae** muscle primarily acts to **elevate the scapula**. Both the rhomboids and levator scapulae are innervated by the **dorsal scapular nerve**. *Supraspinatus and Infraspinatus - Suprascapular nerve* - The **supraspinatus** muscle is involved in initial **abduction of the arm**, while the **infraspinatus** is involved in **external rotation** of the arm. - Both are innervated by the **suprascapular nerve** but are not the primary muscles for scapular retraction and elevation. *Serratus Anterior - Long thoracic nerve* - The **serratus anterior** muscle is primarily responsible for **protraction of the scapula** (pulling it forward) and stabilizing the scapula against the thoracic wall. - It is innervated by the **long thoracic nerve**, and its paralysis leads to **winged scapula**. *Latissimus Dorsi - Thoracodorsal nerve* - The **latissimus dorsi** is a large muscle of the back primarily involved in **adduction**, **extension**, and **internal rotation of the arm** [1]. - It is supplied by the **thoracodorsal nerve** and does not primarily contribute to scapular retraction or elevation [1].

Q: Which intrinsic muscles of the hand are paralyzed if there is hyperextension of the metacarpophalangeal joint and flexion of the interphalangeal joint?

Interossei and lumbricals (both). ***Interossei and lumbricals (both)*** - Paralysis of the **interossei and lumbricals** results in an inability to flex the metacarpophalangeal (MCP) joints and extend the interphalangeal (IP) joints [1]. - This leads to the characteristic "claw hand" deformity, which includes **hyperextension of the MCP joints** and **flexion of the IP joints**. *Thenar muscles* - The thenar muscles (abductor pollicis brevis, flexor pollicis brevis, opponens pollicis) are primarily responsible for movements of the **thumb** [1]. - Their paralysis would affect thumb function (e.g., opposition, abduction) but not directly cause the described deformity in the other digits. *Palmaris brevis* - The palmaris brevis tenses the skin of the palm and helps to deepen the hollow of the hand [1]. - Its paralysis would not have a significant impact on joint positioning or lead to a "claw hand" deformity. *Hypothenar muscles* - The hypothenar muscles (abductor digiti minimi, flexor digiti minimi brevis, opponens digiti minimi) control movements of the **little finger** [1]. - Paralysis of these muscles would affect the little finger's function but would not cause the clawing pattern across all affected digits.

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

Radial nerve. ***Radial nerve*** - Area B represents the sensory distribution of the **radial nerve**, specifically its superficial branch. - The radial nerve provides sensory innervation to the **dorsal (back) aspect of the hand** over the radial (lateral) side, including the thumb, index, middle, and radial half of the ring finger up to the proximal interphalangeal joints. - The superficial branch of the radial nerve also innervates the **anatomical snuffbox** and the radial side of the dorsum of the hand. - **Note:** The radial nerve does NOT supply the palmar surface of the hand; its sensory distribution is limited to the dorsal aspect. *Ulnar nerve* - The ulnar nerve provides sensory innervation to the **medial 1.5 fingers** (little finger and ulnar half of ring finger) on both palmar and dorsal aspects. - It also supplies the **hypothenar eminence** and medial portion of the palm and dorsal hand. - This distribution corresponds to **Area C** in the image, not Area B. *Median nerve* - The median nerve provides sensory innervation to the **lateral 3.5 fingers** (thumb, index, middle, and radial half of ring finger) on the **palmar surface**. - It also supplies the **palmar aspect** of these digits and the **nail beds (dorsal tips)** of the same fingers. - This distribution corresponds to **Area A** in the image, not Area B. *Posterior interosseous nerve* - The **posterior interosseous nerve (PIN)** is a **motor branch** of the radial nerve with no cutaneous sensory distribution. - It supplies the extensor muscles of the posterior forearm compartment. - It does not provide sensory innervation to the skin of the hand.

Q: Identify the marked muscle ‘A’ in the diagram.

Extensor carpi radialis longus. ***Extensor carpi radialis longus*** - Muscle 'A' originates from the **lateral supracondylar ridge of the humerus** and inserts into the base of the second metacarpal, consistent with the **extensor carpi radialis longus (ECRL)**. - The ECRL is part of the **superficial layer** of the posterior compartment of the forearm, responsible for **extension and abduction of the wrist**. *Brachioradialis* - While the brachioradialis also originates from the lateral supracondylar ridge, it is typically more superficial and inserts onto the **styloid process of the radius**, not the metacarpals. - Its primary action is **flexion of the elbow**, rather than wrist extension, and its belly is more anterior relative to the ECRL in this view. *Flexor carpi radialis* - This muscle is located in the **anterior compartment of the forearm** and functions as a **wrist flexor and abductor**. - It originates from the medial epicondyle and inserts into the base of the second and third metacarpals, completely different from the muscle marked 'A'. *Extensor carpi ulnaris* - The extensor carpi ulnaris (ECU) is found on the **ulnar side of the posterior forearm**, originating from the lateral epicondyle and posterior ulna, and inserting into the base of the fifth metacarpal. - Its position is medial to the marked muscle 'A', and it functions to **extend and adduct the wrist**.

Q: The patient is presenting with pain around the base of the thumb. Which tendons are likely involved?

APL & EPB. ***APL & EPB*** - Pain around the base of the thumb, especially with movement, is characteristic of De Quervain's tenosynovitis [1]. This condition involves the **abductor pollicis longus (APL)** and **extensor pollicis brevis (EPB)** tendons [1]. - These two tendons share a common synovial sheath as they pass through the first dorsal compartment of the wrist, making them susceptible to inflammation and friction [1]. *APB & EPL* - **APB (Abductor Pollicis Brevis)** is an intrinsic hand muscle found in the thenar eminence, primarily involved in thumb abduction, and is not typically associated with De Quervain's tenosynovitis. - **EPL (Extensor Pollicis Longus)** is part of the third dorsal compartment and its tendon crosses over the other thumb tendons, and is not inflamed in De Quervain's tenosynovitis. *APB & EPB* - As mentioned, **APB (Abductor Pollicis Brevis)** is an intrinsic hand muscle, not involved in De Quervain's tenosynovitis. - While **EPB (Extensor Pollicis Brevis)** is involved, its combination with APB incorrectly identifies the primary tendons affected in the first dorsal compartment. *APL & EPL* - **APL (Abductor Pollicis Longus)** is one of the correct tendons involved. - **EPL (Extensor Pollicis Longus)** belongs to the third dorsal compartment of the wrist and is not typically affected in De Quervain's tenosynovitis, differentiating it from the tendons in the first dorsal compartment [1].

Question 1

Boundaries of quadrilateral space include all EXCEPT:

Accepted Answer

Deltoid

Answer

Teres major

Answer

Neck of humerus

Answer

Long head of triceps

Question 2

Skin over hypothenar eminence is supplied by?

Accepted Answer

Ulnar nerve

Answer

Radial nerve

Answer

Median nerve

Answer

Anterior interosseous nerve

Question 3

Which nerves primarily supply the small muscles of the hand?

Accepted Answer

Ulnar and Median Nerves

Answer

Radial nerve

Answer

Axillary nerve

Answer

Musculocutaneous nerve

Question 4

Which muscle primarily forms the posterior wall of the axilla?

Accepted Answer

Subscapularis

Answer

Latissimus dorsi

Answer

Teres major

Answer

Pectoralis major

Question 5

Which structure is described as intracapsular but extrasynovial in the shoulder joint?

Accepted Answer

Long head of biceps

Answer

Long head of triceps

Answer

Short head of biceps

Answer

Coracobrachialis

Question 6

Identify the muscles responsible for scapular retraction and elevation. What is their nerve supply?

Accepted Answer

Rhomboids and Levator Scapulae - Dorsal scapular nerve

Answer

Supraspinatus and Infraspinatus - Suprascapular nerve

Answer

Latissimus Dorsi - Thoracodorsal nerve

Answer

Serratus Anterior - Long thoracic nerve

Question 7

Which intrinsic muscles of the hand are paralyzed if there is hyperextension of the metacarpophalangeal joint and flexion of the interphalangeal joint?

Accepted Answer

Interossei and lumbricals (both)

Answer

Thenar muscles

Answer

Hypothenar muscles

Answer

Palmaris brevis

Question 8

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 9

Identify the marked muscle ‘A’ in the diagram.

Accepted Answer

Extensor carpi radialis longus

Answer

Brachioradialis

Answer

Flexor carpi radialis

Answer

Extensor carpi ulnaris

Question 10

The patient is presenting with pain around the base of the thumb. Which tendons are likely involved?

Accepted Answer

APL & EPB

Answer

APB & EPL

Answer

APB & EPB

Answer

APL & EPL

Upper Limb — MCQs

Upper Limb — MCQs

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