Upper Limb Practice Questions

Q: An X-ray of the wrist and hand is shown below. If there is damage to structure E, which of the following muscle weaknesses does it cause?

Flexor carpi ulnaris. ***Flexor carpi ulnaris*** - The **pisiform bone** (structure E) serves as the primary insertion point for the **flexor carpi ulnaris (FCU)**, which is innervated by the **ulnar nerve**. - Damage to the pisiform disrupts FCU function, causing weakness in **wrist flexion** and **ulnar deviation**, as FCU also inserts on the **hook of hamate** and **5th metacarpal base**. *Flexor carpi radialis* - Innervated by the **median nerve** and inserts on the base of the **2nd metacarpal**, not the pisiform bone. - Pisiform damage would not affect FCR function as it has no anatomical relationship with structure E. *Palmaris longus* - Innervated by the **median nerve** and inserts into the **palmar aponeurosis**, completely bypassing the pisiform bone. - This muscle's function remains intact with pisiform damage as it has no connection to structure E. *Brachioradialis* - Innervated by the **radial nerve** and inserts on the **distal radius**, not involving any carpal bones. - Pisiform bone damage has no impact on brachioradialis function due to its separate anatomical pathway and innervation.

Q: What is the nerve supply of the opponens pollicis muscle?

Median nerve. **Explanation:** The **opponens pollicis** is one of the three muscles forming the thenar eminence of the hand. The correct answer is the **Median nerve** [1], specifically its **recurrent branch** (C8, T1). This nerve supplies the "LOAF" muscles: the lateral two Lumbricals, Opponens pollicis, Abductor pollicis brevis, and Flexor pollicis brevis [3]. **Analysis of Options:** * **Median Nerve (Correct):** It provides motor innervation to the thenar muscles. The recurrent branch is often called the "million-dollar nerve" because its injury results in the loss of thumb opposition, severely disabling hand function [1]. * **Deep branch of the ulnar nerve:** This nerve supplies most of the intrinsic muscles of the hand, including the hypothenar muscles, all interossei, and the Adductor pollicis [3]. It does *not* supply the opponens pollicis. * **Superficial branch of the ulnar nerve:** This is primarily sensory to the medial 1.5 fingers and provides motor supply only to the Palmaris brevis [3]. * **Posterior interosseous nerve:** This is a branch of the radial nerve that supplies the extensor compartment of the forearm; it does not innervate any intrinsic hand muscles [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Ape Thumb Deformity:** Caused by a proximal median nerve injury, leading to atrophy of the thenar eminence and loss of opposition. * **Opponens Digiti Minimi:** Unlike the opponens pollicis, this muscle is supplied by the **deep branch of the ulnar nerve** [3]. * **Mnemonic:** Remember **"Meat LOAF"**—**Me**dian nerve supplies **L**umbricals (1&2), **O**pponens pollicis, **A**bductor pollicis brevis, and **F**lexor pollicis brevis.

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

Opponens pollicis. ### 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** (specifically its recurrent branch and digital branches). These five are remembered by the mnemonic **LOAF**: **L**umbricals (1st and 2nd), **O**pponens pollicis, **A**bductor pollicis brevis, and **F**lexor pollicis brevis. [3] **Why the Question/Options are unique:** There appears to be a technical error in the provided key. **Opponens pollicis (A)**, **Abductor pollicis brevis (B)**, and the **First lumbrical (D)** are all classic examples of muscles **supplied** by the Median nerve. The correct answer to "Which is NOT supplied by the median nerve?" is **C. Extensor pollicis brevis**. This is because all **Extensor** muscles of the thumb and wrist are located in the posterior compartment of the forearm and are supplied by the **Posterior Interosseous Nerve (a branch of the Radial nerve)**. [2] **Analysis of Options:** * **Opponens pollicis & Abductor pollicis brevis:** These are Thenar muscles supplied by the recurrent branch of the median nerve (C8, T1). * **First lumbrical:** Supplied by the digital branches of the median nerve. * **Extensor pollicis brevis:** Supplied by the Radial nerve; it is an extrinsic muscle of the hand. [2] **High-Yield Clinical Pearls for NEET-PG:** * **Ape Thumb Deformity:** Caused by Median nerve injury at the wrist (e.g., Carpal Tunnel Syndrome), leading to paralysis of the thenar muscles. [1] * **Million Dollar Nerve:** The recurrent branch of the median nerve is so named because its injury during carpal tunnel surgery leads to loss of thumb opposition, a major disability. * **Ulnar Paradox:** All interossei and the medial two lumbricals are ulnar-supplied. If the median nerve is spared, the index and middle fingers will not show "clawing."

Q: Following anterior dislocation of the shoulder, a patient develops weakness of flexion at the elbow and lack of sensation over the lateral aspect of the forearm. Which nerve is injured?

Musculocutaneous nerve. ### Explanation The correct answer is **Musculocutaneous nerve**. **1. Why it is correct:** The musculocutaneous nerve (C5–C7) arises from the lateral cord of the brachial plexus. It is responsible for: * **Motor supply:** It innervates the muscles of the anterior compartment of the arm—**Coracobrachialis, Biceps brachii, and Brachialis**. Loss of these muscles leads to significant weakness in **elbow flexion** and forearm supination. * **Sensory supply:** After passing through the arm, it continues as the **Lateral cutaneous nerve of the forearm**, providing sensation to the lateral aspect of the forearm. In anterior shoulder dislocations, the humeral head can compress or stretch the cords of the brachial plexus, with the musculocutaneous nerve being a classic, though less common, target than the axillary nerve. **2. Why the other options are incorrect:** * **Radial nerve:** Injury (e.g., mid-shaft humerus fracture) leads to "wrist drop" and loss of extension at the elbow/wrist, not flexion weakness. * **Axillary nerve:** This is the *most common* nerve injured in shoulder dislocations. However, it results in deltoid paralysis (loss of abduction) and sensory loss over the "regimental badge" area (lateral shoulder), not the forearm. * **Ulnar nerve:** Injury causes "claw hand" and sensory loss over the medial 1.5 fingers; it does not affect elbow flexion. **3. NEET-PG High-Yield Pearls:** * **Mnemonic for Musculocutaneous muscles:** **BBC** (Biceps, Brachialis, Coracobrachialis). * **Piercing Nerve:** The musculocutaneous nerve is unique because it **pierces the Coracobrachialis muscle**. * **Dislocation Association:** While the **Axillary nerve** is the most frequently injured in shoulder dislocations, the **Musculocutaneous nerve** is the correct clinical fit when forearm sensory loss and flexion weakness are specified.

Q: Which nerve is involved in this presentation?

Long thoracic Nerve. ***Long thoracic Nerve*** - **Scapular winging** occurs due to paralysis of the **serratus anterior muscle**, which is innervated by the long thoracic nerve (C5-C7). - Loss of serratus anterior function prevents proper **scapular stabilization** against the chest wall, causing the medial border to protrude outward. *Musculocutaneous nerve* - Innervates the **biceps brachii**, **brachialis**, and **coracobrachialis muscles** involved in elbow flexion. - Injury causes weakness in **arm flexion** and sensory loss over the lateral forearm, not scapular winging. *Lateral anterior thoracic nerve* - Innervates the **pectoralis major muscle**, responsible for arm adduction and internal rotation. - Damage results in weakness of **chest adduction** and loss of anterior axillary fold, not scapular protrusion. *Thoracodorsal nerve* - Supplies the **latissimus dorsi muscle**, which performs arm adduction, extension, and internal rotation. - Injury causes weakness in **pulling movements** and loss of posterior axillary fold, but does not affect scapular position.

Q: Which of the following bones has an epiphysis at its base?

Thumb metacarpal. ### Explanation The location of the epiphysis in the tubular bones of the hand follows a specific pattern based on the bone type. This is a high-yield concept for NEET-PG regarding osteology and ossification. During fetal development, most bones are modeled in cartilage and then transformed into bone by ossification [1]. **1. Why the Thumb Metacarpal is Correct:** In the hand, **metacarpals II through V** have their epiphyses at their **heads** (distal end). However, the **1st metacarpal (thumb)** is an exception; its epiphysis is located at its **base** (proximal end) [1]. Regulated bone growth through puberty occurs through epiphysial plates located near the end of the bone shaft [1]. This makes the thumb metacarpal behave developmentally more like a phalanx than a typical metacarpal. **2. Analysis of Incorrect Options:** * **Distal and Middle Phalanges (Options A & B):** All phalanges (proximal, middle, and distal) follow a uniform rule: the epiphysis is always located at the **base** (proximal end). While these bones do have an epiphysis at the base, the question specifically tests the unique "reversal" seen in the metacarpals. * **Third Metacarpal (Option D):** As mentioned, the 2nd, 3rd, 4th, and 5th metacarpals have their epiphyses at the **head** (distal end), not the base. **3. Clinical Pearls & High-Yield Facts:** * **The "Rule of the Base":** All phalanges and the **1st metacarpal** have epiphyses at the base. * **The "Rule of the Head":** Metacarpals **2–5** have epiphyses at the head. * **Pseudo-epiphysis:** Occasionally, an extra epiphysis may appear at the distal end of the 1st metacarpal or the proximal end of the 2nd metacarpal; this is a normal variant and should not be mistaken for a fracture. * **Clavicle Fact:** The clavicle is the first bone to ossify in the body (membranous ossification) but has a secondary epiphysis at its **medial (sternal) end**, which is the last to fuse (around age 25) [1].

Q: Which of the following is NOT a part of the proximal row of carpal bones?

Hamate. The carpal bones are arranged in two rows, each containing four bones. To identify the correct answer, one must distinguish between the **proximal row** (closer to the forearm) and the **distal row** (closer to the metacarpals). [1] ### **Explanation of the Correct Answer** **D. Hamate:** This is the correct answer because the Hamate belongs to the **distal row** of carpal bones. It is characterized by a hook-like process (the hook of the hamate) on its palmar surface [1] and articulates with the 4th and 5th metacarpals. ### **Analysis of Incorrect Options** The proximal row consists of four bones (lateral to medial): * **A. Scaphoid:** The most lateral bone of the proximal row; it articulates with the radius [1] and is the most commonly fractured carpal bone [2]. * **B. Lunate:** Located between the scaphoid and triquetral; it is the most commonly dislocated carpal bone. * **C. Triquetral:** A pyramidal bone located on the medial side of the proximal row, situated proximal to the hamate. *(Note: The **Pisiform**, a sesamoid bone in the tendon of flexor carpi ulnaris, completes the proximal row). ### **High-Yield Clinical Pearls for NEET-PG** * **Mnemonic:** "She Looks Too Pretty, Try To Catch Her" (Scaphoid, Lunate, Triquetral, Pisiform / Trapezium, Trapezoid, Capitate, Hamate). * **Guyon’s Canal:** Formed between the hook of the hamate and the pisiform; it transmits the ulnar nerve and artery [1]. * **Carpal Tunnel:** The scaphoid and trapezium form the lateral wall, while the pisiform and hook of hamate form the medial wall [1]. * **Avascular Necrosis (AVN):** The scaphoid is prone to AVN due to its retrograde blood supply [2].

Q: A 37-year-old man suffers a traumatic injury to the axilla that damages the thoracodorsal nerve. Which of the following movements of the arm or scapula could be affected in this patient?

Adduction. ### Explanation The **thoracodorsal nerve** (C6, C7, C8), a branch of the posterior cord of the brachial plexus, innervates the **Latissimus Dorsi** muscle. To identify the affected movement, one must recall the primary actions of this muscle. **1. Why Adduction is Correct:** The Latissimus Dorsi is a powerful muscle of the posterior axillary wall. Its primary actions on the humerus are **Adduction**, **Extension**, and **Medial (Internal) Rotation**. A lesion to the thoracodorsal nerve results in paralysis of this muscle, significantly weakening the patient's ability to pull the trunk upward (as in climbing) or adduct the arm against resistance. **2. Analysis of Incorrect Options:** * **Abduction (A):** Primarily performed by the Deltoid (axillary nerve) and Supraspinatus (suprascapular nerve). * **Flexion (C):** Primarily performed by the Pectoralis major (clavicular head), Coracobrachialis, and anterior fibers of the Deltoid. Latissimus dorsi is actually an *extensor*. * **Lateral rotation (D):** Performed by the Infraspinatus and Teres minor. Latissimus dorsi is a *medial* rotator. **3. Clinical Pearls for NEET-PG:** * **"Climber’s Muscle":** Latissimus dorsi is essential for climbing and using crutches because it adducts and extends the humerus to lift the body. * **Surgical Significance:** The thoracodorsal nerve is at high risk during **axillary lymph node dissection** (e.g., for breast cancer surgery) or surgeries involving the posterior axillary wall [1]. * **The "Cough" Muscle:** It also aids in forced expiration and coughing. * **Nerve Origin:** Remember the mnemonic "C6, 7, 8—keep the Latissimus straight."

Q: Axillary artery occlusion affects all EXCEPT:

Suprascapular artery. **Explanation:** The **axillary artery** is a direct continuation of the subclavian artery, beginning at the outer border of the first rib and ending at the lower border of the teres major muscle [1]. To answer this question, one must distinguish between the branches of the subclavian artery and the axillary artery. **1. Why Suprascapular Artery is the correct answer:** The **suprascapular artery** is a branch of the **thyrocervical trunk**, which arises from the **first part of the subclavian artery**. Since it originates proximal to the axillary artery, an occlusion of the axillary artery will not affect the flow within the suprascapular artery. In fact, the suprascapular artery plays a vital role in the collateral circulation (scapular anastomosis) to bypass such occlusions. **2. Why the other options are incorrect:** All other options are direct branches of the axillary artery and would be affected by its occlusion [1]: * **Superior thoracic artery:** Arises from the **1st part** of the axillary artery. * **Subscapular artery:** The largest branch, arising from the **3rd part** of the axillary artery. * **Posterior circumflex humeral artery:** Arises from the **3rd part** of the axillary artery (travels through the quadrangular space). **NEET-PG High-Yield Pearls:** * **Scapular Anastomosis:** This vital bypass connects the 1st part of the subclavian artery (via suprascapular and deep branch of transverse cervical arteries) with the 3rd part of the axillary artery (via circumflex scapular branch of the subscapular artery). * **Mnemonics for Axillary branches:** "Save The Lions And Pity Mammals" (Superior thoracic, Thoracoacromial, Lateral thoracic, Alar thoracic/Subscapular, Posterior circumflex, Anterior circumflex). * **Clinical Correlation:** If the axillary artery is ligated between the thyrocervical trunk and the subscapular artery, the scapular anastomosis maintains blood supply to the upper limb [1].

Question 1

An X-ray of the wrist and hand is shown below. If there is damage to structure E, which of the following muscle weaknesses does it cause?

Accepted Answer

Flexor carpi ulnaris

Answer

Flexor carpi radialis

Answer

Palmaris longus

Answer

Brachioradialis

Question 2

What is the nerve supply of the opponens pollicis muscle?

Accepted Answer

Median nerve

Answer

Superficial branch of the ulnar nerve

Answer

Deep branch of the ulnar nerve

Answer

Posterior interosseous nerve

Question 3

Which of the following statements about the scapula is false?

Accepted Answer

The medial border of the scapula indicates a horizontal fissure.

Answer

The root of the spine of the scapula is at the level of T3.

Answer

The inferior angle of the scapula is at the level of T7.

Answer

The lateral angle of the scapula bears the glenoid cavity.

Question 4

Which muscle of the hand is NOT supplied by the median nerve?

Accepted Answer

Opponens pollicis

Answer

Abductor pollicis brevis

Answer

Extensor pollicis brevis

Answer

First lumbrical

Question 5

Following anterior dislocation of the shoulder, a patient develops weakness of flexion at the elbow and lack of sensation over the lateral aspect of the forearm. Which nerve is injured?

Accepted Answer

Musculocutaneous nerve

Answer

Radial nerve

Answer

Axillary nerve

Answer

Ulnar nerve

Question 6

Which nerve is involved in this presentation?

Accepted Answer

Long thoracic Nerve

Answer

Musculocutaneous nerve

Answer

Lateral anterior thoracic nerve

Answer

Thoracodorsal nerve

Question 7

Which of the following bones has an epiphysis at its base?

Accepted Answer

Thumb metacarpal

Answer

Distal phalanx

Answer

Middle phalanx

Answer

Third metacarpal

Question 8

Which of the following is NOT a part of the proximal row of carpal bones?

Accepted Answer

Hamate

Answer

Scaphoid

Answer

Lunate

Answer

Triquetral

Question 9

A 37-year-old man suffers a traumatic injury to the axilla that damages the thoracodorsal nerve. Which of the following movements of the arm or scapula could be affected in this patient?

Accepted Answer

Adduction

Answer

Abduction

Answer

Flexion

Answer

Lateral rotation

Question 10

Axillary artery occlusion affects all EXCEPT:

Accepted Answer

Suprascapular artery

Answer

Posterior circumflex humeral artery

Answer

Subscapular artery

Answer

Superior thoracic artery

Upper Limb — MCQs

Upper Limb — MCQs

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