Upper Limb — MCQs
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Regimental badge anesthesia is due to a lesion of:
Which carpal bone does not articulate with the radius?
The axis of flexion and extension at the elbow joint passes through which of the following structures?
Which of the following nerves is a pure motor nerve that arises from the median nerve?
Which of the following walls of axilla is formed by the surgical neck of humerus:
Which of the following statements about the anterior compartment of the forearm is correct?
What is the classification of the coracoid process in human anatomy?
Which of the following does not pierce the clavipectoral fascia?
Midpalmar space ends distally in which structure?
A person reaches for something on the kitchen shelf, falls on his arm laterally, after which he is unable to extend his wrist, unable to make a strong hand grip, and there is loss of sensation on the dorsum of the hand and fingers. Which of the following structures is involved?
Upper Limb Indian Medical PG Practice Questions and MCQs
Question 811: Regimental badge anesthesia is due to a lesion of:
- A. Axillary nerve (Correct Answer)
- B. Long thoracic nerve
- C. Spinal accessory nerve
- D. Musculocutaneous nerve
Explanation: ***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.
Question 812: Which carpal bone does not articulate with the radius?
- A. Pisiform (Correct Answer)
- B. Scaphoid
- C. Lunate
- D. Triquetrum
Explanation: ***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.
Question 813: The axis of flexion and extension at the elbow joint passes through which of the following structures?
- A. Capitulum
- B. Trochlea (Correct Answer)
- C. Olecranon
- D. Radial styloid
Explanation: ***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.
Question 814: Which of the following nerves is a pure motor nerve that arises from the median nerve?
- A. Posterior interosseous nerve
- B. Ulnar nerve
- C. Anterior interosseous nerve (Correct Answer)
- D. Superficial terminal branch of radial nerve
Explanation: ***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.
Question 815: Which of the following walls of axilla is formed by the surgical neck of humerus:
- A. Medial
- B. Lateral (Correct Answer)
- C. Anterior
- D. Posterior
Explanation: ***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.
Question 816: Which of the following statements about the anterior compartment of the forearm is correct?
- A. Flexor pollicis longus is unipennate. (Correct Answer)
- B. The ulnar nerve enters the forearm by passing between the two heads of pronator teres.
- C. Flexor digitorum profundus originates from the radius.
- D. The median nerve enters the forearm by passing between the two heads of flexor carpi ulnaris.
Explanation: 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].
Question 817: What is the classification of the coracoid process in human anatomy?
- A. Bony projection on the scapula
- B. Type of traction epiphysis (Correct Answer)
- C. Type of pressure epiphysis
- D. Type of atavistic structure
Explanation: ***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 818: Which of the following does not pierce the clavipectoral fascia?
- A. Cephalic vein
- B. Long thoracic nerve (Correct Answer)
- C. Lateral pectoral nerve
- D. Thoracoacromial vessels
Explanation: ***Long thoracic nerve*** - The **long thoracic nerve** (nerve to serratus anterior) typically originates from the **roots of the brachial plexus (C5, C6, C7)** and descends on the superficial surface of the serratus anterior muscle. - It does not pierce the **clavipectoral fascia** but rather lies posterior to it as it courses along the thoracic wall. *Cephalic vein* - The **cephalic vein** ascends in the superficial fascia of the arm, then passes through the **deltopectoral triangle**. - It then pierces the **clavipectoral fascia** to drain into the axillary vein. *Lateral pectoral nerve* - The **lateral pectoral nerve** arises from the **lateral cord of the brachial plexus**. - It pierces the **clavipectoral fascia** to supply the pectoralis major muscle. *Thoracoacromial vessels* - The **thoracoacromial artery and vein** are branches of the axillary vessels. - They pierce the **clavipectoral fascia** to supply the deltoid, pectoral, and subscapular regions.
Question 819: Midpalmar space ends distally in which structure?
- A. Into the web space (Correct Answer)
- B. Along the digital sheaths
- C. Into the flexor tendon sheaths
- D. Distal palmar crease
Explanation: ***Into the web space*** - The **midpalmar space** extends distally to the level of the **web spaces** between the fingers (at the metacarpal heads) [1]. - It is bounded distally by **vertical fibrous septa** that connect the palmar aponeurosis to the deep transverse metacarpal ligament at the web spaces. - These septa prevent distal spread of infections beyond the web space level. - This anatomical boundary is clinically important in understanding the spread of **midpalmar space infections** [1]. *Distal palmar crease* - The **distal palmar crease** is a surface landmark that lies **more proximal** than the actual distal extent of the midpalmar space. - While it's a useful clinical landmark, it does not represent the true anatomical distal boundary of the midpalmar space. - The space extends beyond this crease to reach the web spaces. *Along the digital sheaths* - While infections in the midpalmar space can potentially support spread to involve the fingers, the space itself does not directly terminate "along" the digital sheaths. - The **digital flexor tendon sheaths** are distinct anatomical structures within the fingers. *Into the flexor tendon sheaths* - The midpalmar space surrounds the flexor tendons but is separated from the **flexor tendon sheaths** by synovial membranes. - While infections can spread between these spaces in severe cases, the midpalmar space does not anatomically "end" in the tendon sheaths.
Question 820: A person reaches for something on the kitchen shelf, falls on his arm laterally, after which he is unable to extend his wrist, unable to make a strong hand grip, and there is loss of sensation on the dorsum of the hand and fingers. Which of the following structures is involved?
- A. Brachial plexus
- B. C7 radiculopathy
- C. Posterior cord injury
- D. Radial nerve injury (Correct Answer)
Explanation: ***Radial nerve injury*** - The inability to **extend the wrist** (**wrist drop**) and loss of sensation on the **dorsum of the hand** and fingers are classic signs of **radial nerve injury**. - The radial nerve innervates the **extensor muscles** of the forearm and hand and provides sensory innervation to the dorsal aspect of the hand. - The mechanism of injury (lateral fall on arm) suggests injury to the radial nerve in the **spiral groove** of the humerus, which is the most common site for radial nerve compression injury. *Brachial plexus* - A brachial plexus injury typically presents with more widespread neurological deficits affecting multiple nerves and muscle groups, often involving the entire arm or specific parts depending on the plexus level affected. - While it could lead to radial nerve dysfunction, the specific constellation of symptoms points directly to the radial nerve rather than a broader plexus injury. *C7 radiculopathy* - **C7 radiculopathy** primarily affects the **triceps (extension of the elbow)**, wrist flexors, and some finger extensors, but the sensory loss pattern is typically along the C7 dermatome (middle finger) and may not include the entire dorsum of the hand. - The prominent **wrist drop** is more characteristic of radial nerve injury. *Posterior cord injury* - The **posterior cord** gives rise to the radial and axillary nerves. An injury here would affect both the **radial nerve** and the **axillary nerve**. - An **axillary nerve injury** manifests as **deltoid weakness** (inability to abduct the arm), which is not described in this patient's symptoms.
Practice by Chapter
Pectoral Region and Axilla
Practice Questions
Arm and Cubital Fossa
Practice Questions
Forearm and Hand
Practice Questions
Joints of Upper Limb
Practice Questions
Nerves of Upper Limb
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Arterial Supply and Venous Drainage
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Lymphatic Drainage
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Muscles and Their Actions
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Applied Anatomy and Clinical Correlations
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Surface Anatomy and Landmarks
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