Upper Limb Practice Questions

Q: Which intrinsic muscle of the hand is not supplied by the median nerve?

Adductor pollicis brevis. ### Explanation The intrinsic muscles of the hand are primarily supplied by the **Ulnar nerve**, with the exception of five muscles supplied by the **Median nerve**. These five are commonly remembered by the mnemonic **"LOAF"** (Lumbricals 1 & 2, Opponens pollicis, Abductor pollicis brevis, and Flexor pollicis brevis). [1] **Why Option D is Correct:** **Adductor pollicis** is the only muscle of the thenar eminence (the ball of the thumb) that is **not** supplied by the median nerve. It is supplied by the **deep branch of the ulnar nerve (C8, T1)**. It functions to adduct the thumb, bringing it toward the palm. **Why the Other Options are Incorrect:** * **A & B (Abductor pollicis brevis & Opponens pollicis):** These are part of the thenar muscle group supplied by the **recurrent branch of the median nerve**. * **C (First lumbrical):** The first and second (lateral) lumbricals are supplied by the **median nerve**, whereas the third and fourth (medial) lumbricals are supplied by the ulnar nerve. [1] **High-Yield Clinical Pearls for NEET-PG:** 1. **Ape Thumb Deformity:** Caused by median nerve injury at the wrist (e.g., Carpal Tunnel Syndrome), leading to atrophy of the thenar eminence and loss of thumb opposition. [1] 2. **Froment’s Sign:** Tests for ulnar nerve palsy. Since the **Adductor pollicis** is paralyzed, the patient compensates by using the Flexor Pollicis Longus (Median nerve) to grip paper, resulting in flexion of the thumb IP joint. 3. **Flexor pollicis brevis (FPB):** This muscle often has a **dual nerve supply** (superficial head by median nerve, deep head by ulnar nerve). [1]

Q: A person riding a mountain bike on a rustic trail hits a rut, the fork of the bike breaks and the person is thrown into a tree, severely fracturing the upper end of his humerus. During the repair, the surgeon ties off the artery traveling through the quadrangular space to stop the hemorrhage. Which artery did he ligate?

Posterior circumflex humeral. The correct answer is **Posterior circumflex humeral artery**. This question tests your knowledge of the surgical anatomy of the axillary spaces and their contents. **1. Why the Correct Answer is Right:** The **Quadrangular Space** is a vital anatomical gateway in the posterior shoulder. Its boundaries are: * **Superior:** Teres minor muscle * **Inferior:** Teres major muscle * **Medial:** Long head of the triceps brachii * **Lateral:** Surgical neck of the humerus The two structures passing through this space are the **Axillary nerve** and the **Posterior circumflex humeral artery**. In fractures of the surgical neck of the humerus, these structures are at high risk of injury. Ligation of this artery [1] is often necessary during surgical repair to control hemorrhage. **2. Why Other Options are Wrong:** * **Dorsal scapular artery (A):** Arises from the subclavian artery and travels along the medial border of the scapula, deep to the levator scapulae and rhomboids. * **Scapular circumflex artery (C):** This is a branch of the subscapular artery that passes through the **Triangular Space** (bounded by Teres minor, Teres major, and Long head of triceps). * **Subscapular artery (D):** The largest branch of the axillary artery (3rd part); it stays on the anterior surface of the subscapularis muscle before dividing into the circumflex scapular and thoracodorsal arteries. **3. Clinical Pearls for NEET-PG:** * **Surgical Neck Fracture:** Always look for damage to the **Axillary Nerve** (loss of deltoid contour/abduction) and **Posterior Circumflex Humeral Artery** [1]. * **Triangular Space:** Contains only the Scapular circumflex artery. * **Triangular Interval:** Contains the **Radial Nerve** and **Profunda Brachii Artery**. * **Anastomosis:** The posterior circumflex humeral artery anastomoses with the anterior circumflex humeral artery around the surgical neck.

Q: At what age is the ossification center of the upper end of the ulna united?

16 years. The ossification of the long bones of the upper limb is a high-yield topic for NEET-PG, specifically regarding the timeline of appearance and fusion of epiphyses. [1] ### **Explanation of the Correct Answer** The upper end of the ulna (the olecranon process) typically develops from one or two secondary ossification centers. These centers appear around the age of **8–10 years**. The fusion of this epiphysis with the shaft (diaphysis) occurs during puberty, specifically around **14–16 years** in males and slightly earlier in females. Therefore, **16 years** represents the completion of the union process. ### **Analysis of Incorrect Options** * **A (9 years):** This is the age when the ossification center for the olecranon typically **appears**, not when it unites. * **B (11 years):** At this age, the ossification center is active and growing, but the growth plate (epiphyseal plate) remains open. * **C (14 years):** While fusion can begin at 14, standard anatomical texts (like Gray’s Anatomy and Chaurasia) cite 16 years as the definitive age of union for the upper end of the ulna. ### **Clinical Pearls & High-Yield Facts** * **Direction of Nutrient Foramen:** Remember the rule: *"To the elbow I go, from the knee I flee."* In the ulna, the nutrient foramen is directed upwards (towards the elbow), meaning the **upper end is the growing end**. * **Exception to the Rule:** Paradoxically, even though the upper end is the "growing end," it fuses **earlier** (16 years) than the lower end (18–20 years). * **Medico-legal Importance:** Determining the fusion of the olecranon and the fusion of the lower end of the radius/ulna is a primary method used in forensic radiology to estimate the age of adolescents between 14 and 20 years.

Q: Pointing index sign is seen in which nerve palsy?

Median. **Explanation:** The **Pointing Index Sign** (also known as the **Ochsner’s Test** or **Hand of Benediction** when attempting to make a fist) is a classic clinical feature of a **high median nerve palsy** (lesion at or above the elbow). **Why Median Nerve is Correct:** The median nerve innervates the **Flexor Digitorum Superficialis (FDS)** and the lateral half of the **Flexor Digitorum Profundus (FDP)** (which goes to the index and middle fingers) [1]. When a patient with a high median nerve lesion attempts to clench their fist, they cannot flex the IP joints of the index and middle fingers. Consequently, the index finger remains straight (pointing), while the ring and little fingers flex normally (as their FDP supply from the ulnar nerve remains intact). **Why other options are incorrect:** * **Ulnar Nerve:** Palsy leads to a "Claw Hand" (hyperextension at MCP joints and flexion at IP joints of the ring and little fingers) due to paralysis of the medial lumbricals and interossei. * **Radial Nerve:** Palsy typically results in "Wrist Drop" or "Finger Drop" due to paralysis of the extensors of the wrist and fingers. * **Axillary Nerve:** Palsy results in the loss of shoulder abduction (deltoid paralysis) and sensory loss over the "regimental badge" area; it does not affect finger movement. **High-Yield Clinical Pearls for NEET-PG:** * **Ape Thumb Deformity:** Seen in low median nerve palsy (at the wrist) due to thenar muscle atrophy and loss of thumb opposition [1]. * **Froment’s Sign:** Used to test for Ulnar nerve palsy (weakness of Adductor Pollicis). * **Kiloh-Nevin Syndrome:** Isolated paralysis of the Flexor Pollicis Longus and FDP to the index finger due to **Anterior Interosseous Nerve (AIN)** involvement (a branch of the median nerve), resulting in an inability to make the "OK" sign.

Q: The midpalmar space of the hand communicates with all the following structures except?

Fascial sheath of the 1st lumbrical. **Explanation:** The **midpalmar space** is a deep fascial space of the hand located medial to the intermediate palmar septum [1]. Understanding its boundaries and communications is crucial for predicting the spread of hand infections. **1. Why Option B is correct:** The midpalmar space communicates distally with the **fascial sheaths of the 2nd, 3rd, and 4th lumbrical muscles** (which pass through the 2nd, 3rd, and 4th web spaces). The **1st lumbrical** is located in the **thenar space**, not the midpalmar space. Therefore, an infection in the midpalmar space will not directly track into the 1st lumbrical canal. **2. Why the other options are incorrect:** * **Forearm space (Space of Parona):** Proximally, the midpalmar space is continuous with the forearm space deep to the flexor tendons via the carpal tunnel. * **Fascial sheaths of 2nd and 3rd lumbricals:** These canals serve as the primary distal drainage/communication routes for the midpalmar space. The 2nd lumbrical corresponds to the index finger, and the 3rd to the middle finger. **High-Yield Clinical Pearls for NEET-PG:** * **Boundaries:** The midpalmar space is separated from the thenar space by a fibrous septum attached to the **3rd metacarpal bone** [1]. * **Clinical Presentation:** Infections here result in the loss of the normal concavity of the palm ("ballooning" of the palm) [1]. * **Kanavel’s Signs:** While primarily for tenosynovitis, remember that midpalmar space infections often occur secondary to neglected tenosynovitis of the middle, ring, or little fingers. * **The "U-Bursa" Communication:** The synovial sheath of the little finger is usually continuous with the common flexor sheath (ulnar bursa), which lies in the midpalmar space.

Q: An isolated avulsion fracture of the lesser tubercle of the humerus in a 16-year-old athlete is caused by the forceful contraction of which of the following muscles?

Subscapularis. The correct answer is **Subscapularis**. This question tests your knowledge of functional anatomy and muscle insertions on the proximal humerus. **1. Why Subscapularis is correct:** The **lesser tubercle** of the humerus serves as the specific insertion point for only one rotator cuff muscle: the **Subscapularis**. An avulsion fracture occurs when a tendon or ligament pulls a fragment of bone away from the main body. In young athletes, forceful external rotation or sudden contraction of the subscapularis (often during sports like wrestling or throwing) can lead to an isolated avulsion of the lesser tubercle. **2. Why the other options are incorrect:** * **Supraspinatus, Infraspinatus, and Teres minor:** These three muscles collectively insert onto the **greater tubercle** of the humerus. * **Supraspinatus:** Inserts on the superior impression. * **Infraspinatus:** Inserts on the middle impression. * **Teres minor:** Inserts on the inferior impression. An avulsion of the greater tubercle would involve one or more of these muscles, not the subscapularis. **3. Clinical Pearls & High-Yield Facts for NEET-PG:** * **Rotator Cuff Mnemonic (SITS):** **S**upraspinatus, **I**nfraspinatus, **T**eres minor (all Greater Tubercle) and **S**ubscapularis (Lesser Tubercle). * **Function:** The Subscapularis is the primary **internal rotator** of the humerus. * **Nerve Supply:** It is supplied by the **Upper and Lower Subscapular nerves** (C5, C6). * **Clinical Test:** The **Lift-off test** or **Belly-press test** is used to assess the integrity of the subscapularis muscle/tendon. * **Bicipital Groove:** Located between the greater and lesser tubercles, it lodges the long head of the biceps brachii tendon. The **Latissimus dorsi** inserts into the floor of this groove.

Q: Which of the following is a subcutaneous muscle?

Palmaris brevis. The correct answer is **Palmaris brevis**. In anatomy, a **subcutaneous muscle** (or muscle of the panniculus carnosus) is one that is located within the superficial fascia and inserts directly into the skin rather than onto bone [1]. * **Palmaris Brevis:** This is a thin, quadrilateral muscle located in the superficial fascia of the hypothenar eminence [1]. It originates from the palmar aponeurosis and flexor retinaculum and inserts into the **dermis of the skin** on the ulnar border of the hand. Its primary function is to wrinkle the skin of the hypothenar eminence and deepen the hollow of the palm, improving grip [1]. **Analysis of Incorrect Options:** * **Sternocleidomastoid:** A major muscle of the neck that lies deep to the platysma. It originates from the sternum/clavicle and inserts into the mastoid process (bone). * **Mylohyoid:** A suprahyoid muscle forming the floor of the oral cavity; it attaches to the mylohyoid line of the mandible. * **Palmaris Longus:** A vestigial muscle of the forearm. While its tendon is superficial, it is a skeletal muscle that inserts into the palmar aponeurosis, not the skin. **Clinical Pearls for NEET-PG:** 1. **Ulnar Nerve:** The palmaris brevis is unique because it is the **only** muscle supplied by the **superficial branch of the ulnar nerve** [1]. 2. **Protection:** It serves to protect the underlying ulnar artery and nerve from pressure during gripping. 3. **Other Subcutaneous Muscles:** Other examples include the **Platysma** (neck) and the **muscles of facial expression**.

Q: Damage to the floor of the anatomic snuffbox and origin of the abductor pollicis brevis most likely involves which of the following bones?

Trapezium. ### Explanation The correct answer is **Trapezium (Option B)**. This question tests your knowledge of the bony landmarks of the wrist and the origins of the intrinsic muscles of the hand. **1. Why Trapezium is Correct:** The **anatomic snuffbox** is a triangular depression on the radial aspect of the wrist. Its floor is formed by two bones: the **Scaphoid** (proximally) and the **Trapezium** (distally) [1]. Furthermore, the **Abductor Pollicis Brevis (APB)**—a member of the thenar muscle group—takes its origin from the tubercle of the trapezium and the associated flexor retinaculum [1]. Therefore, a bone that contributes to both the floor of the snuffbox and the origin of the APB must be the trapezium. **2. Why Other Options are Incorrect:** * **Scaphoid (Option A):** While the scaphoid forms the proximal part of the snuffbox floor and is the most commonly fractured carpal bone [1], it is **not** the origin for the abductor pollicis brevis. * **Lunate (Option C):** The lunate is located in the proximal row of carpal bones but is situated medially to the scaphoid. It does not form the snuffbox floor nor serve as an origin for thenar muscles. * **Capitate (Option D):** The capitate is the largest carpal bone, located centrally in the distal row. It does not contribute to the radial-sided anatomic snuffbox. **Clinical Pearls for NEET-PG:** * **Snuffbox Boundaries:** Lateral (Abductor pollicis longus & Extensor pollicis brevis); Medial (Extensor pollicis longus) [1]. * **Contents:** The **Radial Artery** passes through the snuffbox. * **Tenderness:** Tenderness in the snuffbox classically indicates a **Scaphoid fracture**, which carries a high risk of avascular necrosis (AVN) due to retrograde blood supply [1]. * **Thenar Muscles (Meat):** Remember the mnemonic **OAF** (Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis)—all primarily originate from the trapezium and flexor retinaculum [1].

Question 1

Hyperextension at the metacarpophalangeal joints and flexion at the interphalangeal joints is caused by injury to which nerve?

Accepted Answer

Ulnar nerve

Answer

Radial nerve

Answer

Median nerve

Answer

Musculocutaneous nerve

Question 2

Which intrinsic muscle of the hand is not supplied by the median nerve?

Accepted Answer

Adductor pollicis brevis

Answer

Abductor pollicis brevis

Answer

Opponens pollicis

Answer

First lumbrical

Question 3

A person riding a mountain bike on a rustic trail hits a rut, the fork of the bike breaks and the person is thrown into a tree, severely fracturing the upper end of his humerus. During the repair, the surgeon ties off the artery traveling through the quadrangular space to stop the hemorrhage. Which artery did he ligate?

Accepted Answer

Posterior circumflex humeral

Answer

Dorsal scapular

Answer

Scapular circumflex

Answer

Subscapular

Question 4

At what age is the ossification center of the upper end of the ulna united?

Accepted Answer

16 years

Answer

9 years

Answer

11 years

Answer

14 years

Question 5

A 45-year-old woman has a severe asthmatic exacerbation and requires an arterial blood gas specimen for management. If you are planning to draw the sample from the brachial artery, where should you insert the needle?

Accepted Answer

Just medial to the biceps tendon in the cubital fossa

Answer

In the lateral aspect of the arm, between the biceps and triceps brachii muscles

Answer

Just lateral to the biceps tendon in the cubital fossa

Answer

Just medial to the tendon of the flexor carpi radialis muscle at the wrist

Question 6

Pointing index sign is seen in which nerve palsy?

Accepted Answer

Median

Answer

Ulnar

Answer

Radial

Answer

Axillary

Question 7

The midpalmar space of the hand communicates with all the following structures except?

Accepted Answer

Fascial sheath of the 1st lumbrical

Answer

Forearm space

Answer

Fascial sheath of the 2nd lumbrical

Answer

Fascial sheath of the 3rd lumbrical

Question 8

An isolated avulsion fracture of the lesser tubercle of the humerus in a 16-year-old athlete is caused by the forceful contraction of which of the following muscles?

Accepted Answer

Subscapularis

Answer

Teres minor

Answer

Supraspinatus

Answer

Infraspinatus

Question 9

Which of the following is a subcutaneous muscle?

Accepted Answer

Palmaris brevis

Answer

Sternocleidomastoid

Answer

Mylohyoid

Answer

Palmaris longus

Question 10

Damage to the floor of the anatomic snuffbox and origin of the abductor pollicis brevis most likely involves which of the following bones?

Accepted Answer

Trapezium

Answer

Scaphoid

Answer

Lunate

Answer

Capitate

Upper Limb — MCQs

Upper Limb — MCQs

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