Upper Limb Practice Questions

Q: Paralysis of which muscle causes Froment's sign?

Adductor pollicis. ***Adductor pollicis*** - **Froment's sign** is a clinical test to assess for **ulnar nerve palsy**, specifically weakness of the **adductor pollicis muscle** [1]. - When the adductor pollicis is weak, the patient compensates by flexing the **interphalangeal joint** of the thumb using the **flexor pollicis longus** (median nerve innervation), leading to the characteristic 'pinching' deformity. *Opponens pollicis* - Paralysis of the opponens pollicis, innervated by the **median nerve**, would primarily impair **thumb opposition** [1]. - This would result in an inability to touch the thumb to the tips of other fingers, but not the specific compensation seen in Froment's sign. *Abductor pollicis* - The **abductor pollicis longus** (radial nerve) and **abductor pollicis brevis** (median nerve) are responsible for **abducting the thumb** [1]. - Weakness of these muscles would affect the ability to move the thumb away from the palm, which is distinct from Froment's sign. *Adductor hallucis longus* - The **adductor hallucis** is a muscle in the **foot** responsible for **adduction of the great toe**. - Its paralysis would have no direct effect on thumb function or **Froment's sign**, which is a hand-specific test.

Q: Regimental badge anesthesia is due to a lesion of:

Axillary nerve. ***Axillary nerve*** - A lesion of the **axillary nerve** causes sensory loss over the lateral part of the shoulder, often described as a **regimental badge anesthesia**, due to damage to its **superior lateral cutaneous nerve** branch. - The axillary nerve can be injured in cases of **anterior shoulder dislocation** or **fractures of the surgical neck of the humerus**. *Long thoracic nerve* - Injury to the long thoracic nerve primarily leads to weakness and paralysis of the **serratus anterior muscle**, causing **scapular winging**. - It does not typically present with sensory deficits on the shoulder. *Spinal accessory nerve* - A lesion of the spinal accessory nerve results in weakness of the **sternocleidomastoid** and **trapezius muscles**, leading to difficulty shrugging the shoulder and turning the head. - This nerve is purely motor and does not carry sensory fibers for the shoulder region. *Musculocutaneous nerve* - A lesion of the musculocutaneous nerve causes weakness in forearm flexion (biceps brachii, brachialis) and sensory loss over the **lateral forearm** (lateral antebrachial cutaneous nerve). - It does not innervate the shoulder for sensation.

Q: A patient presents with a brachial plexus injury and exhibits signs of Horner's syndrome. Which nerve root level is primarily involved?

T1. ***T1*** - Involvement of the **T1 nerve root** is crucial because it carries **preganglionic sympathetic fibers** that ascend to the superior cervical ganglion [1]. - Damage to these fibers at the T1 level, often due to a **lower brachial plexus injury (Klumpke's palsy)**, interrupts the sympathetic pathway to the head, leading to **Horner's syndrome** [1]. *C5* - The **C5 nerve root** primarily contributes to the **upper trunk** of the brachial plexus and innervates muscles like the deltoid and biceps. - Injury to C5 typically results in deficits related to **shoulder abduction** and **elbow flexion**, not Horner's syndrome. *C6* - The **C6 nerve root** also contributes to the upper and middle trunks, innervating muscles responsible for **wrist extension** and **elbow flexion**. - Damage to C6 would primarily cause weakness in these movements and sensory loss in the thumb and index finger. *C7* - The **C7 nerve root** forms the middle trunk and innervates muscles like the triceps and wrist flexors. - Injury to C7 would lead to deficits in **elbow extension** and **wrist flexion**, and sensory loss in the middle finger.

Q: The axis of flexion and extension at the elbow joint passes through which of the following structures?

Trochlea. ***Trochlea*** - The **axis of flexion and extension at the elbow joint** (also called the carrying angle axis) passes through the **trochleo-capitellar region**, with the **trochlea forming the medial component** of this axis. - The **trochlea** articulates with the trochlear notch of the ulna and is the **primary structure** defining the medial aspect of the elbow's rotational axis. - This axis runs from the inferior aspect of the medial epicondyle, through the center of the trochlea and capitulum, to the inferior aspect of the lateral epicondyle. - In clinical and anatomical contexts, when asked about "the axis of the upper limb" at the elbow, **trochlea is the most appropriate answer** as it represents the dominant medial component. *Capitulum* - The **capitulum** forms the lateral part of the elbow axis and articulates with the head of the radius. - While the flexion-extension axis passes through the trochleo-capitellar region (including the capitulum), the **trochlea is considered the primary structure** as it provides the main hinge mechanism through its articulation with the ulna. *Olecranon* - The **olecranon** is the proximal end of the ulna, forming the prominent posterior bony point of the elbow. - It articulates with the **olecranon fossa** during extension and serves as the attachment for the triceps muscle. - The olecranon **rotates around the axis** but does not define the axis itself. *Radial styloid* - The **radial styloid process** is located at the distal end of the radius at the wrist. - It is involved in wrist articulation but is not related to the axis of the elbow joint.

Q: Which of the following nerves is a pure motor nerve that arises from the median nerve?

Anterior interosseous nerve. ***Anterior interosseous nerve*** - This nerve is a **pure motor nerve** that branches off the **median nerve** in the forearm. - It innervates the **flexor pollicis longus**, **flexor digitorum profundus (lateral half)**, and **pronator quadratus muscles**. *Ulnar nerve* - The ulnar nerve is a **mixed nerve** (sensory and motor) and does not arise from the median nerve. - It originates from the **medial cord of the brachial plexus**. *Posterior interosseous nerve* - This nerve is a **pure motor nerve** but it arises from the **radial nerve**, not the median nerve. - It innervates most of the **extensor muscles** of the forearm. *Superficial terminal branch of radial nerve* - This branch is primarily **sensory**, providing innervation to the dorsum of the hand and digits. - It arises from the **radial nerve**, not the median nerve, and is not a pure motor nerve.

Q: Which carpal bone does not articulate with the radius?

Pisiform. ***Pisiform*** - The **pisiform** is a sesamoid bone located within the tendon of the **flexor carpi ulnaris** muscle. - It articulates only with the **triquetrum**, not directly with the radius. *Scaphoid* - The **scaphoid** is one of the carpal bones that directly articulates with the radius, forming part of the **radiocarpal joint**. - It is located in the **proximal row** of carpal bones on the lateral side. *Lunate* - The **lunate** is another bone in the proximal carpal row that articulates directly with the **radius**, alongside the scaphoid. - It plays a crucial role in wrist movement and stability. *Triquetrum* - The **triquetrum** is a carpal bone in the proximal row, located medially. - Although it is in the proximal row, it primarily articulates with the **ulnar articular disc** (triangular fibrocartilage complex), which separates it from the distal ulna, and does not directly articulate with the radius.

Q: Which of the following statements about the anterior compartment of the forearm is correct?

Flexor pollicis longus is unipennate.. The flexor pollicis longus is unipennate. - The **flexor pollicis longus** muscle has a **unipennate** architecture, meaning its muscle fibers insert obliquely into one side of a central tendon. - This specific arrangement provides efficient force generation for thumb flexion. *The ulnar nerve enters the forearm by passing between the two heads of pronator teres.* - This is **incorrect**. The **ulnar nerve** enters the forearm by passing **between the two heads of flexor carpi ulnaris** (humeral and ulnar heads), not pronator teres. - The nerve that passes between the heads of pronator teres is the **median nerve**. *Flexor digitorum profundus originates from the radius.* - This is **incorrect**. The **flexor digitorum profundus** originates primarily from the **anterior and medial surfaces of the ulna** and the **interosseous membrane**, not from the radius. - The muscle arising from the radius in the anterior compartment is the **flexor pollicis longus**. *The median nerve enters the forearm by passing between the two heads of flexor carpi ulnaris.* - This is **incorrect**. The **median nerve** enters the forearm by passing **between the two heads of pronator teres** (humeral and ulnar heads), not flexor carpi ulnaris [1]. - The nerve that passes between the heads of flexor carpi ulnaris is the **ulnar nerve** [1].

Q: Which of the following walls of axilla is formed by the surgical neck of humerus:

Lateral. ***Lateral*** - The **lateral wall** of the axilla is formed by the **surgical neck of the humerus** and the coracobrachialis and biceps brachii muscles as they pass down into the arm. - This wall provides the main connection between the axilla and the arm proper. *Anterior* - The **anterior wall** is formed by the **pectoralis major** [1] and **pectoralis minor** muscles [1], along with the clavipectoral fascia. - This wall also forms the anterior axillary fold. *Posterior* - The **posterior wall** is comprised of the **subscapularis**, **teres major**, and **latissimus dorsi** muscles [1]. - It forms the posterior axillary fold. *Medial* - The **medial wall** of the axilla is formed by the **upper four or five ribs** along with the **serratus anterior muscle**. - This wall lies against the chest wall.

Q: What is the classification of the coracoid process in human anatomy?

Type of traction epiphysis. ***Type of traction epiphysis*** - A **traction epiphysis** is a site of muscle attachment that experiences significant tensile stress, influencing bone growth and development. - The **coracoid process** serves as an attachment point for several muscles (e.g., pectoralis minor, coracobrachialis, biceps brachii short head) and ligaments, making it a classic example of a traction epiphysis. *Bony projection on the scapula* - While it is a **bony projection**, this description is too generic and doesn't capture the specific developmental and functional classification. - Many bony projections exist throughout the skeleton without being specifically classified as a traction epiphysis. *Type of pressure epiphysis* - A **pressure epiphysis** is primarily involved in weight-bearing and transmitting pressure, commonly found at the ends of long bones. - The coracoid process's main function is not weight-bearing but rather muscle and ligament attachment. *Type of atavistic structure* - An **atavistic structure** refers to a re-emergence of a trait that had disappeared generations before. - While evolutionary remnants exist in human anatomy, the coracoid process has a clear and continuous functional role, so it is not considered atavistic.

Question 1

Paralysis of which muscle causes Froment's sign?

Accepted Answer

Adductor pollicis

Answer

Abductor pollicis

Answer

Adductor hallucis longus

Answer

Opponens pollicis

Question 2

Regimental badge anesthesia is due to a lesion of:

Accepted Answer

Axillary nerve

Answer

Long thoracic nerve

Answer

Spinal accessory nerve

Answer

Musculocutaneous nerve

Question 3

Physical examination reveals weakness of medial deviation of the wrist (adduction), loss of sensation on the medial side of the hand, and clawing of the fingers. Where is the most likely place of injury?

Accepted Answer

Compression of a nerve passing between the humeral and ulnar heads of origin of flexor carpi ulnaris

Answer

Compression of a nerve passing through the carpal tunnel

Answer

Compression of a nerve passing between the humeral and ulnar heads of origin of flexor digitorum superficialis

Answer

Compression of a nerve at Guyon's canal between the pisiform bone and the hook of the hamate.

Question 4

A patient presents with a brachial plexus injury and exhibits signs of Horner's syndrome. Which nerve root level is primarily involved?

Accepted Answer

T1

Answer

C5

Answer

C6

Answer

C7

Question 5

The axis of flexion and extension at the elbow joint passes through which of the following structures?

Accepted Answer

Trochlea

Answer

Capitulum

Answer

Olecranon

Answer

Radial styloid

Question 6

Which of the following nerves is a pure motor nerve that arises from the median nerve?

Accepted Answer

Anterior interosseous nerve

Answer

Posterior interosseous nerve

Answer

Ulnar nerve

Answer

Superficial terminal branch of radial nerve

Question 7

Which carpal bone does not articulate with the radius?

Accepted Answer

Pisiform

Answer

Scaphoid

Answer

Lunate

Answer

Triquetrum

Question 8

Which of the following statements about the anterior compartment of the forearm is correct?

Accepted Answer

Flexor pollicis longus is unipennate.

Answer

The ulnar nerve enters the forearm by passing between the two heads of pronator teres.

Answer

Flexor digitorum profundus originates from the radius.

Answer

The median nerve enters the forearm by passing between the two heads of flexor carpi ulnaris.

Question 9

Which of the following walls of axilla is formed by the surgical neck of humerus:

Accepted Answer

Lateral

Answer

Medial

Answer

Answer

Posterior

Question 10

What is the classification of the coracoid process in human anatomy?

Accepted Answer

Type of traction epiphysis

Answer

Bony projection on the scapula

Answer

Type of pressure epiphysis

Answer

Type of atavistic structure

Upper Limb — MCQs

Upper Limb — MCQs

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