Surface Anatomy and Landmarks — MCQs

10 questions

A patient at the orthopedics OPD complains of troubled sleep at night due to numbness and tingling sensation involving his lateral 3 digits. His symptoms are relieved as he lays his arms hanging from the bed. Which of the following options correctly describes his condition and the test used to assess it?

Which structure is NOT part of the anatomical snuffbox?

Which statement considering the relations of nerves to the humerus is the most accurate?

Fracture shaft of humerus can cause damage to which of the following nerves?

Which artery passes through the anatomical snuffbox?

The lateral boundary of the cubital fossa is formed by

Which of the following structures passes deep to the flexor retinaculum at the wrist along with the tendon of flexor digitorum profundus?

The image shows a highlighted region on the dorsal aspect of the hand (anatomical snuffbox). Which of the following anatomical structures form the boundaries or floor of this region?

Which bone connects the sternum to the scapula?

Q10

Sensory supply of the palm is from which nerves?

Surface Anatomy and Landmarks Indian Medical PG Practice Questions and MCQs

Question 1: A patient at the orthopedics OPD complains of troubled sleep at night due to numbness and tingling sensation involving his lateral 3 digits. His symptoms are relieved as he lays his arms hanging from the bed. Which of the following options correctly describes his condition and the test used to assess it?

A. Guyon's canal syndrome, Froment's test
B. Carpal tunnel syndrome, Froment's test
C. Guyon's canal syndrome, Durkan's test
D. Carpal tunnel syndrome, Durkan's test (Correct Answer)

Explanation: ***Carpal tunnel syndrome, Durkan's test*** - The symptoms of **numbness and tingling** in the **lateral 3 digits** (thumb, index, middle, and radial half of the ring finger) are classic for **carpal tunnel syndrome (CTS)**, caused by compression of the **median nerve**. Relief with hanging the arm is due to gravity reducing swelling and pressure. - **Durkan's test** (or **median nerve compression test**) is highly specific for CTS. It involves direct pressure over the carpal tunnel, reproducing symptoms within 30 seconds. *Guyon's canal syndrome, Froment's test* - **Guyon's canal syndrome** involves compression of the **ulnar nerve** at the wrist, primarily affecting the **little finger** and the **ulnar half of the ring finger**, not the lateral 3 digits. - **Froment's test** assesses **ulnar nerve palsy** by observing the strength of adductor pollicis during a pinch grip, which is unrelated to median nerve compression. *Carpal tunnel syndrome, Froment's test* - While **carpal tunnel syndrome** is correctly identified based on the symptoms, **Froment's test** is not used to assess it. - As mentioned, Froment's test evaluates **ulnar nerve function**, particularly the adductor pollicis muscle. *Guyon's canal syndrome, Durkan's test* - The symptoms described (lateral 3 digits) are inconsistent with **Guyon's canal syndrome**, which affects the ulnar nerve distribution. - Although **Durkan's test** is appropriate for carpal tunnel syndrome, the diagnosis for Guyon's canal syndrome is incorrect.

Question 2: Which structure is NOT part of the anatomical snuffbox?

A. Extensor pollicis brevis
B. Flexor carpi ulnaris (Correct Answer)
C. Abductor pollicis longus
D. Extensor pollicis longus

Explanation: ***Flexor carpi ulnaris*** - The **flexor carpi ulnaris** is located on the ulnar side of the forearm and wrist, contributing to wrist flexion and adduction. - It is not a boundary or content of the **anatomical snuffbox**, which is formed by tendons on the radial side of the wrist. *Extensor pollicis brevis* - This tendon forms the **lateral (radial) boundary** of the **anatomical snuffbox** along with the **abductor pollicis longus** [1]. - It extends the **metacarpophalangeal joint** of the thumb [1]. *Abductor pollicis longus* - This tendon forms the **lateral (radial) boundary** of the **anatomical snuffbox** along with the **extensor pollicis brevis** [1]. - It primarily **abducts** and **extends** the thumb at the **carpometacarpal joint** [1]. *Extensor pollicis longus* - This tendon forms the **medial (ulnar) boundary** of the **anatomical snuffbox** [1]. - It extends the **interphalangeal joint** of the thumb and contributes to its extension at the metacarpophalangeal and carpometacarpal joints.

Question 3: Which statement considering the relations of nerves to the humerus is the most accurate?

A. Deltoid may atrophy following shoulder dislocation. (Correct Answer)
B. The median nerve runs in the spiral groove.
C. The axillary nerve runs around the anatomical neck.
D. Mid-shaft humeral fractures will usually result in complete paralysis of triceps.

Explanation: **Deltoid may atrophy following shoulder dislocation.** - **Shoulder dislocations**, particularly anterior dislocations, frequently injure the **axillary nerve** due to its close proximity to the humeral head and surgical neck. - Damage to the axillary nerve, which innervates the **deltoid muscle**, can lead to deltoid paralysis and subsequent **atrophy**, resulting in a flattened shoulder contour and impaired abduction. *The median nerve runs in the spiral groove.* - The **radial nerve**, not the median nerve, runs in the **spiral groove** (radial groove) of the humerus [1]. - The median nerve travels more anteriorly in the arm, alongside the brachial artery. *The axillary nerve runs around the anatomical neck.* - The **axillary nerve** wraps around the **surgical neck** of the humerus, not the anatomical neck. - The surgical neck is a common site for fractures, making the axillary nerve vulnerable to injury in such cases. *Mid-shaft humeral fractures will usually result in complete paralysis of triceps.* - Mid-shaft humeral fractures primarily risk damage to the **radial nerve**, which innervates the lateral and medial heads of the triceps [1]. - However, the **long head of the triceps** is innervated by the radial nerve more proximally and may remain partially functional, preventing complete paralysis of the entire triceps muscle.

Question 4: Fracture shaft of humerus can cause damage to which of the following nerves?

A. Ulnar nerve
B. Radial nerve (Correct Answer)
C. Axillary nerve
D. Median nerve

Explanation: ***Radial nerve*** - The **radial nerve** runs in the **spiral groove** along the posterior aspect of the humerus shaft, making it highly susceptible to injury during a fracture in this region. - Damage can lead to **wrist drop** and impaired sensation over the posterior forearm and hand. *Ulnar nerve* - The **ulnar nerve** primarily runs along the medial epicondyle of the humerus, making it more vulnerable to injuries around the **elbow joint**, not typically the humeral shaft. - Injury to the ulnar nerve results in a characteristic **"claw hand"** deformity and sensory loss over the medial aspect of the hand. *Axillary nerve* - The **axillary nerve** wraps around the surgical neck of the humerus and is most commonly injured with **shoulder dislocations** or fractures involving the surgical neck, not the shaft. - Damage to the axillary nerve causes weakness in **deltoid abduction** and sensory loss over the lateral shoulder (regimental badge area). *Median nerve* - The **median nerve** travels more anteriorly and medially in the arm and is generally protected from direct injury in a mid-shaft humeral fracture. - Injury to the median nerve can cause a **"ape hand" deformity** and sensory loss over the radial aspect of the palm.

Question 5: Which artery passes through the anatomical snuffbox?

A. Radial artery (Correct Answer)
B. Brachial artery
C. Ulnar artery
D. Interosseus artery

Explanation: ***Radial artery*** - The **radial artery** is palpable within the **anatomical snuffbox**, as it courses over the scaphoid and trapezium bones towards the deep palmar arch. - This location is clinically significant for feeling the pulse and is vulnerable to injury, especially during **scaphoid fractures**. *Brachial artery* - The **brachial artery** is found in the **arm**, typically running in the cubital fossa, well proximal to the anatomical snuffbox. - It bifurcates into the radial and ulnar arteries at the level of the elbow, not within the wrist structures. *Ulnar artery* - The **ulnar artery** typically lies on the **medial side of the forearm** and wrist, contributing to the superficial palmar arch. - It does not pass through the anatomical snuffbox, which is located on the lateral aspect of the wrist. *Interosseus artery* - The **interosseus arteries** (anterior and posterior) run between the radius and ulna in the forearm, supplying muscles and bones. - These arteries are deep within the forearm compartments and do not traverse the superficial anatomical snuffbox at the wrist.

Question 6: The lateral boundary of the cubital fossa is formed by

A. Biceps
B. Brachialis
C. Brachioradialis (Correct Answer)
D. Pronator teres

Explanation: ***Brachioradialis*** - The **brachioradialis muscle** forms the **lateral boundary** of the cubital fossa. - It originates from the lateral supracondylar ridge of the humerus and inserts on the distal radius. - This muscle is a **flexor of the elbow** and assists in bringing the forearm to a neutral position from pronation or supination. *Pronator teres* - The **pronator teres muscle** forms the **medial boundary** of the cubital fossa. - It originates from the medial epicondyle of the humerus and coronoid process of the ulna, inserting on the lateral surface of the radius. - This muscle is primarily responsible for **pronation of the forearm** and assists in elbow flexion. *Brachialis* - The **brachialis muscle** forms part of the **floor of the cubital fossa** (along with the supinator muscle). - It lies deep to the biceps brachii and inserts on the coronoid process and ulnar tuberosity. - It is a powerful **elbow flexor**, acting directly on the ulna. *Biceps* - The **biceps brachii** does not form a boundary of the cubital fossa. - Its **tendon passes through the fossa** as content, while the **bicipital aponeurosis** contributes to the roof. - The biceps is a major flexor and supinator of the forearm.

Question 7: Which of the following structures passes deep to the flexor retinaculum at the wrist along with the tendon of flexor digitorum profundus?

A. Ulnar nerve
B. Median nerve (Correct Answer)
C. Radial nerve
D. Ulnar artery

Explanation: ***Median nerve*** - The **median nerve** passes through the **carpal tunnel**, deep to the **flexor retinaculum**, along with the tendons of the **flexor digitorum superficialis**, **flexor digitorum profundus**, and **flexor pollicis longus** [1]. - Compression of the **median nerve** in this confined space leads to **carpal tunnel syndrome**. *Ulnar nerve* - The **ulnar nerve** passes *superficial* to the **flexor retinaculum** within **Guyon's canal**, not deep to it [1]. - It accompanies the **ulnar artery** in this canal. *Radial nerve* - The **radial nerve** typically passes over the **anatomical snuffbox** or more proximally around the lateral epicondyle; it does not pass *deep* to the **flexor retinaculum** at the wrist. - Its superficial branch can be found on the dorsum of the hand. *Ulnar artery* - The **ulnar artery** passes *superficial* to the **flexor retinaculum**, alongside the **ulnar nerve**, within **Guyon's canal** [1]. - It contributes to the blood supply of the hand, forming the superficial palmar arch.

Question 8: The image shows a highlighted region on the dorsal aspect of the hand (anatomical snuffbox). Which of the following anatomical structures form the boundaries or floor of this region?

A. Abductor pollicis longus muscle.
B. Styloid process of the radius.
C. Extensor pollicis longus muscle.
D. All of the above anatomical structures. (Correct Answer)

Explanation: ***All of the above anatomical structures.*** - The image highlights the **anatomical snuffbox**, a triangular depression on the radial dorsal aspect of the hand. Its boundaries are formed by the tendons of the **extensor pollicis longus muscle** (ulnar side), and the **abductor pollicis longus** and **extensor pollicis brevis muscles** (radial side). - The **styloid process of the radius** forms the floor of the anatomical snuffbox along with the scaphoid and trapezium bones. All the options listed are key anatomical features associated with this region. *Extensor pollicis longus muscle.* - This muscle forms the **ulnar (medial) border** of the anatomical snuffbox. - Its tendon can be palpated during **thumb extension** and contributes to the overall structure of the highlighted area. *Abductor pollicis longus muscle.* - This muscle, along with the extensor pollicis brevis, forms the **radial (lateral) border** of the anatomical snuffbox. - Its tendon is visible and palpable on the radial side of the highlighted region when the thumb is abducted. *Styloid process of the radius.* - This bony prominence is located at the **distal end of the radius** on the radial side of the wrist. - It forms part of the **proximal floor** of the anatomical snuffbox, contributing to its definition.

Question 9: Which bone connects the sternum to the scapula?

A. Clavicle (Correct Answer)
B. First rib
C. Manubrium
D. Second rib

Explanation: ***Clavicle*** - The **clavicle**, or collarbone, is the only bone that directly connects the **axial skeleton** (via the sternum) to the **appendicular skeleton** (via the scapula). - It articulates medially with the **manubrium** of the sternum at the sternoclavicular joint and laterally with the **acromion** of the scapula at the acromioclavicular joint. *First rib* - The **first rib** articulates with the **manubrium** of the sternum but does not connect directly to the scapula. - Its primary role is to form part of the **thoracic cage**, protecting internal organs. *Manubrium* - The **manubrium** is the superior part of the **sternum** and articulates with the clavicles and the first two ribs. - It does not directly connect to the **scapula**; rather, the clavicle mediates this connection. *Second rib* - The **second rib** articulates with both the **manubrium** and the body of the sternum at the **sternal angle**. - Like the first rib, it is part of the **thoracic cage** and does not directly connect to the scapula.

Question 10: Sensory supply of the palm is from which nerves?

A. Median nerve and Radial nerve
B. Radial nerve and ulnar nerve
C. Ulnar nerve and Median nerve (Correct Answer)
D. Musculocutaneous nerve and Radial nerve

Explanation: **Ulnar nerve and Median nerve** *(Correct)* - The **median nerve** provides sensory innervation to the lateral palm, including the thumb, index, middle, and radial half of the ring finger [1]. - The **ulnar nerve** supplies sensory innervation to the medial palm, including the little finger and the ulnar half of the ring finger [1]. - Together, these two nerves provide complete sensory coverage of the palm [1]. *Median nerve and Radial nerve* (Incorrect) - While the **median nerve** innervates a significant portion of the palm, the **radial nerve** primarily supplies the dorsal aspect of the hand and a small area of the thenar eminence, not the entire palm. - The radial nerve's sensory supply to the palm is usually limited to a very small area at the base of the thumb. - This combination does not provide complete palmar sensory coverage. *Radial nerve and ulnar nerve* (Incorrect) - The **radial nerve** mainly supplies the dorsum of the hand and digits, with minimal palmar contribution, making this option incorrect for primary palmar sensory supply. - The **ulnar nerve** does innervate part of the palm, but the combination with the radial nerve for complete palmar supply is inaccurate. - The median nerve, not the radial nerve, is the other major contributor to palmar sensation. *Musculocutaneous nerve and Radial nerve* (Incorrect) - The **musculocutaneous nerve** primarily innervates the lateral aspect of the forearm (as the lateral antebrachial cutaneous nerve) and does not contribute to the sensory supply of the palm. - The **radial nerve** also has a limited role in palmar sensation. - Neither of these nerves provides significant sensory innervation to the palm.

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