Upper Limb Practice Questions

Q: The median nerve supplies all of the following muscles except?

Flexor Carpi Ulnaris. **Explanation:** The **Median Nerve** is the primary nerve of the anterior (flexor) compartment of the forearm. It supplies all the muscles in this compartment **except for 1.5 muscles**: the Flexor Carpi Ulnaris (FCU) and the medial half (ulnar half) of the Flexor Digitorum Profundus (FDP) [1]. These 1.5 muscles are supplied by the **Ulnar Nerve** [1]. **Analysis of Options:** * **A. Flexor Carpi Ulnaris (Correct):** This muscle is exclusively supplied by the **Ulnar Nerve (C8, T1)**. It is a key landmark for the ulnar nerve and artery at the wrist. * **B. Flexor Digitorum Superficialis:** This is a superficial muscle of the forearm supplied entirely by the Median Nerve before it passes through the carpal tunnel [1]. * **C. Pronator Teres:** This is the most lateral of the superficial flexors and is supplied by the Median Nerve. * **D. Flexor Pollicis Longus:** This is a deep muscle of the forearm supplied by the **Anterior Interosseous Nerve (AIN)**, which is a major branch of the Median Nerve. **High-Yield Clinical Pearls for NEET-PG:** * **Point of Compression:** The median nerve can be compressed between the two heads of the **Pronator Teres** (Pronator Syndrome) or under the flexor retinaculum (**Carpal Tunnel Syndrome**) [1]. * **The "1.5" Rule:** Always remember that the Ulnar nerve "steals" the FCU and the medial half of the FDP. * **Hand of Benediction:** This deformity occurs when a patient attempts to make a fist but cannot flex the index and middle fingers due to a high median nerve palsy. * **Mnemonic:** The Median nerve supplies the **LOAF** muscles in the hand (Lumbricals 1 & 2, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis).

Q: A 38-year-old man sustained a motor vehicular accident and subsequently lost the ability to abduct his right shoulder and flex his elbow. What is the most likely cause?

Upper trunk injury. ### Explanation **1. Why Upper Trunk Injury is Correct:** The clinical presentation describes a classic case of **Erb’s Palsy**, which results from an injury to the **Upper Trunk (C5-C6)** of the brachial plexus. * **Abduction loss:** Due to paralysis of the **Deltoid** (Axillary nerve, C5-C6) and **Supraspinatus** (Suprascapular nerve, C5-C6). * **Elbow flexion loss:** Due to paralysis of the **Biceps brachii** and **Brachialis** (Musculocutaneous nerve, C5-C6). In high-impact trauma like motor vehicle accidents, forceful displacement of the head away from the shoulder stretches or tears these roots, leading to the characteristic "Policeman’s tip" or "Waiter’s tip" deformity (arm adducted, medially rotated, and forearm extended/pronated). **2. Why Other Options are Incorrect:** * **Shoulder Dislocation:** While it can cause axillary nerve damage (loss of abduction), it typically does not affect elbow flexion (musculocutaneous nerve). * **Medial Cord Injury (C8-T1):** This would primarily affect the intrinsic muscles of the hand (Ulnar nerve) and medial aspect of the forearm, leading to "Claw hand" rather than proximal shoulder/elbow deficits. * **Lateral Cord Injury:** While it involves the musculocutaneous nerve (flexion loss), it does not account for the loss of abduction mediated by the suprascapular and axillary nerves (which arise from the trunk and posterior cord, respectively). **3. Clinical Pearls for NEET-PG:** * **Erb’s Point:** A site on the upper trunk where 6 nerves meet (C5, C6 roots; Suprascapular, Nerve to Subclavius; Anterior and Posterior divisions). * **Klumpke’s Palsy:** Lower trunk injury (C8-T1) resulting from hyper-abduction of the arm; presents with "Total Claw Hand." * **Nerve Roots:** Remember C5-C6 for "proximal" movements (Shoulder/Elbow) and C8-T1 for "distal" movements (Hand).

Q: Klumpke's palsy is due to injury to which part of the brachial plexus?

Inferior trunk. **Explanation:** **Klumpke’s Palsy** (Dejerine-Klumpke paralysis) is a form of brachial plexus injury resulting from a lesion of the **inferior (lower) trunk**, which carries fibers from the **C8 and T1** nerve roots. 1. **Why Option A is Correct:** The injury typically occurs due to hyper-abduction of the arm (e.g., clutching an object while falling from a height or a breech delivery). The T1 fibers primarily supply the **intrinsic muscles of the hand** (interossei, thenar, and hypothenar muscles). Loss of these muscles leads to an imbalance between the long flexors and extensors, resulting in the characteristic **"Total Claw Hand"** deformity. 2. **Why Other Options are Incorrect:** * **Superior Trunk (B):** Injury here (C5-C6) leads to **Erb’s Palsy**, characterized by the "Waiter’s tip" deformity (adducted, internally rotated arm with extended elbow). * **Subscapular Nerve (C):** This nerve arises from the posterior cord and supplies the subscapularis and teres major; its injury would affect internal rotation but not cause claw hand. * **Ulnar Nerve (D):** While ulnar nerve damage causes a "partial" claw hand (affecting the 4th and 5th digits), Klumpke’s palsy involves both ulnar and median-supplied intrinsic muscles, leading to a more severe total clawing. **High-Yield Clinical Pearls for NEET-PG:** * **Site of Lesion:** Lower Trunk (C8-T1). * **Deformity:** Total Claw Hand (hyperextension at MCP joints, flexion at IP joints). * **Associated Feature:** **Horner’s Syndrome** (miosis, ptosis, anhidrosis) may be present if the T1 preganglionic sympathetic fibers are involved. * **Sensory Loss:** Occurs along the medial aspect of the forearm and hand (ulnar border).

Q: Claw hand is caused by which of the following conditions?

Ulnar nerve palsy. **Explanation:** **Claw hand (Main en griffe)** is the characteristic clinical deformity resulting from **Ulnar nerve palsy**, typically due to a lesion at the wrist or elbow. [1] **Why Ulnar Nerve Palsy is correct:** The ulnar nerve innervates the **medial two lumbricals** and all **interossei**. These muscles normally flex the metacarpophalangeal (MCP) joints and extend the interphalangeal (IP) joints. In ulnar nerve palsy, these actions are lost, leading to the opposite posture: **hyperextension at the MCP joints** (due to unopposed action of long extensors) and **flexion at the IP joints** (due to unopposed action of long flexors). This primarily affects the ring and little fingers. **Why other options are incorrect:** * **Median nerve palsy:** Results in "Ape thumb deformity" (loss of thumb opposition) or "Hand of Benediction" (when attempting to make a fist). [2] * **Radial nerve palsy:** Leads to **Wrist drop** and finger drop due to paralysis of the extensors of the wrist and fingers. * **Anterior interosseous nerve palsy:** Affects the deep flexors of the thumb and index finger, resulting in an inability to make the "OK" sign (Pinch deformity). [2] **High-Yield Clinical Pearls for NEET-PG:** * **Ulnar Paradox:** A lesion at the **wrist** causes a *more severe* clawing than a lesion at the elbow. This is because, in high lesions (elbow), the Flexor Digitorum Profundus is also paralyzed, reducing the flexion at the IP joints. * **Froment’s Sign:** Positive in ulnar nerve palsy due to paralysis of the Adductor Pollicis (patient compensates by flexing the thumb IP joint using the median nerve). * **Total Claw Hand:** Occurs in **Klumpke’s Paralysis** (C8-T1 injury), where both ulnar and median nerve-innervated intrinsic muscles are affected.

Q: What is the largest carpal bone?

Capitate. The **Capitate** is the largest and most central bone of the carpus. Its name is derived from the Latin word *caput* (head), referring to its rounded proximal projection that fits into the concavity formed by the Scaphoid and Lunate bones. It occupies a pivotal position in the distal row of carpal bones and serves as the center of rotation for the entire wrist. **Analysis of Options:** * **Capitate (Correct):** It is the largest carpal bone. It is also the **first bone to begin ossification** (usually at 1–3 months of age), making it a key landmark in pediatric bone age assessment. * **Scaphoid (Incorrect):** While it is the largest bone in the **proximal row** and the most commonly fractured carpal bone, it is smaller than the Capitate. * **Lunate (Incorrect):** This is a crescent-shaped bone in the proximal row. It is clinically significant as the most commonly dislocated carpal bone, but it is relatively small. * **Trapezoid (Incorrect):** This is the smallest bone in the distal row and sits between the Scaphoid and the second metacarpal. **High-Yield NEET-PG Pearls:** 1. **Ossification Sequence:** Remember the mnemonic **"C-H-T-L-T-T-S-P"** (Capitate, Hamate, Triquetrum, Lunate, Trapezium, Trapezoid, Scaphoid, Pisiform). Capitate is first; Pisiform is last (9–12 years). 2. **Smallest Carpal Bone:** The **Pisiform** (a sesamoid bone in the tendon of Flexor Carpi Ulnaris). 3. **Clinical Correlation:** The head of the Capitate articulates with the Lunate; in perilunate dislocations, the Capitate is typically displaced dorsally.

Q: Upper boundary of quadrangular space is formed by?

Teres minor. The **Quadrangular Space** is a clinically significant anatomical gap located in the posterior scapular region. It serves as a conduit for neurovascular structures passing from the axilla to the posterior arm. ### **Anatomical Boundaries** To master this topic, visualize the space as a four-sided window: * **Superior (Upper):** **Teres minor** (anteriorly) and the capsule of the shoulder joint. * **Inferior (Lower):** **Teres major** muscle. * **Medial:** **Long head of triceps brachii**. * **Lateral:** **Surgical neck of the humerus**. ### **Analysis of Options** * **Teres minor (Correct):** Forms the superior boundary. In some texts, the Subscapularis is also mentioned as the anterior-superior boundary, but Teres minor is the standard posterior-superior landmark. * **Teres major (Incorrect):** This muscle forms the **inferior** boundary of the space. * **Long head of triceps (Incorrect):** This forms the **medial** boundary, separating the quadrangular space from the triangular space. * **Surgical neck of humerus (Incorrect):** This forms the **lateral** boundary. ### **High-Yield Clinical Pearls for NEET-PG** 1. **Contents:** The space transmits the **Axillary nerve** and the **Posterior circumflex humeral artery**. 2. **Quadrangular Space Syndrome:** Compression of the axillary nerve in this space (often in overhead athletes) leads to atrophy of the deltoid and teres minor muscles and sensory loss over the "regimental badge" area. 3. **The "Rule of Teres":** Remember that **Minor is Superior** and **Major is Inferior** in the boundaries of both the quadrangular and triangular spaces.

Question 1

The median nerve supplies all of the following muscles except?

Accepted Answer

Flexor Carpi Ulnaris

Answer

Flexor digitorum Superficialis

Answer

Pronator teres

Answer

Flexor Pollicis Longus

Question 2

A 38-year-old man sustained a motor vehicular accident and subsequently lost the ability to abduct his right shoulder and flex his elbow. What is the most likely cause?

Accepted Answer

Upper trunk injury

Answer

Shoulder dislocation

Answer

Medial cord injury

Answer

Lateral cord injury

Question 3

Palmar interossei are absent in which of the following digits?

Accepted Answer

Middle finger

Answer

Thumb

Answer

Ring finger

Answer

Little finger

Question 4

Klumpke's palsy is due to injury to which part of the brachial plexus?

Accepted Answer

Inferior trunk

Answer

Superior trunk

Answer

Subscapular nerve

Answer

Ulnar nerve

Question 5

Which level in the axillary group of lymph nodes does the apical group belong to?

Accepted Answer

Level III

Answer

Level I

Answer

Level II

Answer

Supraclavicular

Question 6

Claw hand is caused by which of the following conditions?

Accepted Answer

Ulnar nerve palsy

Answer

Median nerve palsy

Answer

Radial nerve palsy

Answer

Anterior interosseous nerve palsy

Question 7

What is the largest carpal bone?

Accepted Answer

Capitate

Answer

Trapezoid

Answer

Scaphoid

Answer

Lunate

Question 8

Upper boundary of quadrangular space is formed by?

Accepted Answer

Teres minor

Answer

Teres major

Answer

Long head of triceps

Answer

Surgical neck of humerus

Question 9

A patient woke up with difficulty in extending fingers, could make a grip and hold a pen. Dorsiflexion was normal. Sensory and motor examination was normal. Which nerve is most commonly involved?

Accepted Answer

Posterior interosseous nerve

Answer

C8T1 nerve roots

Answer

Lower brachial plexus

Answer

Hand area in cortex

Question 10

In high ulnar nerve lesions, such as those resulting from elbow fractures or dislocations, the degree of clawing is markedly less than in low ulnar nerve lesions. This phenomenon is called the ulnar paradox. What is the reason for the ulnar paradox?

Accepted Answer

The ulnar half of the flexor digitorum profundus (FDP) is paralyzed, leading to no active flexion at the interphalangeal (IP) joints.

Answer

The lumbrical muscles are spared, preventing the development of clawing.

Answer

The median nerve compensates for the function of the ulnar nerve.

Answer

The interosseous muscles increase their tone and extend the IP joints.

Upper Limb — MCQs

Upper Limb — MCQs

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