Upper Limb Practice Questions

Q: The lateral antebrachial cutaneous nerve originates from which nerve?

Musculocutaneous nerve. The **lateral antebrachial cutaneous nerve** is the terminal sensory continuation of the **musculocutaneous nerve**. After the musculocutaneous nerve (C5–C7) pierces the coracobrachialis and supplies the muscles of the anterior compartment of the arm (biceps brachii and brachialis), it emerges lateral to the biceps tendon at the elbow. At this point, it pierces the deep fascia to become the lateral antebrachial cutaneous nerve, providing sensation to the skin of the lateral aspect of the forearm. **Analysis of Incorrect Options:** * **Axillary nerve:** Supplies the deltoid and teres minor muscles and terminates as the *upper lateral cutaneous nerve of the arm* (supplying the "regimental badge" area). * **Medial cord nerve:** The medial cord gives rise to the *medial antebrachial cutaneous nerve*, which supplies the skin of the medial forearm. * **Radial nerve:** Gives rise to the *posterior antebrachial cutaneous nerve* and the *lower lateral cutaneous nerve of the arm*, but not the lateral cutaneous nerve of the forearm. **Clinical Pearls for NEET-PG:** * **Site of Injury:** The musculocutaneous nerve is most commonly injured by heavy lifting or trauma to the axilla. Loss of the lateral antebrachial cutaneous nerve results in anesthesia over the lateral forearm. * **Biceps Reflex:** The musculocutaneous nerve mediates the afferent and efferent limbs of the **C5-C6** biceps tendon reflex. * **Anatomical Landmark:** The nerve passes between the biceps brachii and brachialis muscles before becoming superficial.

Q: Enumerate the two structures passing through the quadrangular space of the back.

Posterior circumflex humeral artery and Axillary nerve.. The **Quadrangular Space** is a clinically significant anatomical gap located in the posterior scapular region. It serves as a vital passageway for neurovascular structures moving from the axilla to the posterior arm. **1. Why Option C is Correct:** The boundaries of the quadrangular space are formed by the Teres minor (superior), Teres major (inferior), long head of Triceps (medial), and the surgical neck of the humerus (lateral). The two structures that traverse this space are: * **Axillary Nerve:** Supplies the deltoid and teres minor muscles. * **Posterior Circumflex Humeral Artery:** Provides blood supply to the shoulder joint and surrounding muscles. **2. Analysis of Incorrect Options:** * **Option A:** The **Suprascapular artery and nerve** pass through/above the suprascapular notch, not the quadrangular space. * **Option B:** The **Subscapular artery** branches into the circumflex scapular artery, which passes through the *Triangular Space*. * **Option D:** The **Profunda brachii artery and Radial nerve** pass through the **Lower Triangular Space** (also known as the Triangular Interval), located inferior to the quadrangular space. **3. Clinical Pearls for NEET-PG:** * **Quadrangular Space Syndrome:** Compression of the axillary nerve in this space (often by fibrous bands or hypertrophy of muscles) leads to weakness in shoulder abduction and atrophy of the deltoid. * **Surgical Neck Fracture:** Fractures at the surgical neck of the humerus most commonly damage the structures within the quadrangular space, particularly the **Axillary nerve**. * **High-Yield Mnemonic:** Remember the "Triangular Interval" contains the **Radial** nerve (R for Radial, R for Interval).

Q: A suspect is brought in after sustaining a gunshot wound to the arm, resulting in damage to the median nerve. Which of the following symptoms is likely produced by this nerve damage?

Ape hand. The **Median Nerve** is often referred to as the "Laborer’s Nerve." Damage to this nerve, particularly at the level of the arm or elbow (high lesion), results in the loss of supply to the **thenar muscles** (Abductor pollicis brevis, Flexor pollicis brevis, and Opponens pollicis). [1] **Why "Ape Hand" is correct:** When the thenar muscles atrophy, the thumb loses its ability to abduct and oppose. It falls back into the same plane as the rest of the fingers due to the unopposed action of the Adductor pollicis (supplied by the Ulnar nerve). This flattened appearance of the palm resembles the hand of a simian, hence the term **Ape Hand deformity**. **Analysis of Incorrect Options:** * **A. Waiter’s tip hand:** This is characteristic of **Erb’s Palsy** (injury to the upper trunk of the brachial plexus, C5-C6). The arm hangs by the side, medially rotated and pronated. * **B. Claw hand:** This results from **Ulnar nerve** injury. It is characterized by hyperextension at the metacarpophalangeal (MCP) joints and flexion at the interphalangeal (IP) joints, most prominent in the ring and little fingers. [1] * **C. Wrist drop:** This is the hallmark of **Radial nerve** injury (often due to mid-shaft humerus fractures), resulting in the paralysis of the extensors of the wrist and digits. [1] **High-Yield Clinical Pearls for NEET-PG:** * **Pointing Index/Benedict’s Hand:** When a patient with a high median nerve lesion tries to make a fist, the index and middle fingers remain extended (due to loss of Flexor Digitorum Profundus and Superficialis). * **Million Dollar Nerve:** The recurrent branch of the median nerve; its injury causes Ape Hand without sensory loss. * **Supracondylar Fracture of Humerus:** The most common cause of high median nerve palsy in children. [1]

Q: All of the following are true about the clavicle, except:

No treatment required for fracture but rest. The clavicle is a unique bone with several high-yield anatomical and clinical characteristics. This question tests the distinction between anatomical facts and clinical management. ### **Explanation of the Correct Answer (A)** Option **A** is the "except" (incorrect statement) because clavicle fractures **do require treatment**, even if it is non-surgical. While most fractures are managed conservatively, they require more than just "rest." Standard treatment involves immobilization using a **Figure-of-8 bandage** or a **triangular broad arm sling** for 3–6 weeks to provide stability, reduce pain, and facilitate union. Complete lack of treatment can lead to symptomatic malunion or non-union. ### **Analysis of Incorrect Options (True Statements)** * **B. Breaks at the midpoint:** This is true. The junction of the medial two-thirds and lateral one-third is the weakest point of the bone because it is where the curvature changes. Approximately 80% of clavicle fractures occur here. * **C. First bone to ossify:** This is a classic embryological fact. The clavicle is the first bone in the human body to begin ossification (around the 5th–6th week of intrauterine life). * **D. Ossifies in membrane:** Unlike most long bones that undergo endochondral ossification, the clavicle undergoes **intramembranous ossification** (except for its ends). ### **NEET-PG High-Yield Pearls** * **Unique Features:** It is the only long bone that lies horizontally, has no medullary cavity, and is the only long bone to ossify in membrane. * **Nerve Injury:** The most common nerve structure at risk in displaced fractures is the **Brachial Plexus** (specifically the divisions). * **Surgical Indications:** Surgery (ORIF with plate) is indicated for open fractures, neurovascular injury, skin tenting, or significant shortening (>2 cm). * **Most Common Site of Non-union:** The lateral third (Type II Neer fractures).

Q: Several deficits in muscle function of the right upper limb were noted, including inability to abduct the arm. This was caused by denervation of which muscle?

Deltoid. **Explanation:** The **Deltoid** muscle is the primary abductor of the arm. Abduction of the humerus occurs in a coordinated sequence: the first 0–15° is initiated by the supraspinatus, while the **Deltoid** is responsible for the major range of abduction from **15° to 90°**. Beyond 90°, rotation of the scapula by the serratus anterior and trapezius is required. Denervation of the deltoid (typically via the **Axillary nerve**) results in a profound inability to abduct the arm. **Analysis of Incorrect Options:** * **B. Infraspinatus:** This is a rotator cuff muscle primarily responsible for **lateral (external) rotation** of the arm. * **C. Latissimus dorsi:** Known as the "climber's muscle," its primary actions are **adduction, extension, and medial rotation** of the humerus. * **D. Teres minor:** Part of the rotator cuff, it assists in **lateral rotation** and weak adduction. Like the deltoid, it is supplied by the axillary nerve, but its loss does not prevent abduction. **NEET-PG High-Yield Pearls:** * **Nerve Supply:** The Deltoid is supplied by the **Axillary Nerve (C5, C6)**, which travels through the quadrangular space. * **Clinical Sign:** Axillary nerve injury (often due to surgical neck of humerus fracture or shoulder dislocation) leads to deltoid atrophy, resulting in the **"loss of rounded contour of the shoulder."** * **Sensory Check:** Always check for sensation over the **"Regimental Badge area"** (lower half of the deltoid) to assess axillary nerve integrity.

Q: Which of the following statements regarding brachial plexus injuries is NOT true?

Erb's palsy involves injury to C5, C6, C7 roots.. ### Explanation **1. Why Option A is the Correct Answer (The False Statement):** Erb’s palsy is caused by an injury to the **Upper Trunk** of the brachial plexus, specifically involving the **C5 and C6 nerve roots** (not C7). The site of injury is known as **Erb’s point**, where six nerves meet. While C7 is occasionally involved in extensive injuries, the classic definition for NEET-PG focuses strictly on C5 and C6. **2. Analysis of Other Options:** * **Option B:** Klumpke’s palsy is indeed a **Lower Trunk** injury involving **C8 and T1**. It typically results from hyperabduction of the arm (e.g., clutching a tree branch while falling). * **Option C:** Horner’s syndrome (miosis, ptosis, anhidrosis) occurs in lower plexus injuries because the **T1 root** carries sympathetic fibers destined for the eye. Its presence indicates a pre-ganglionic avulsion of the T1 root. * **Option D:** In Erb’s palsy, the arm hangs by the side (adducted), is medially rotated, and the forearm is extended and pronated. This characteristic posture is classically described as the **'Waiter’s tip'** or **'Policeman’s tip'** deformity. **3. High-Yield Clinical Pearls for NEET-PG:** * **Muscles paralyzed in Erb’s:** Biceps, Deltoid, Brachialis, and Brachioradialis (mainly). * **Deformity in Klumpke’s:** "Claw hand" due to paralysis of intrinsic hand muscles. * **Sensory Loss:** Erb’s palsy shows loss over the lateral aspect of the arm (deltoid region); Klumpke’s shows loss along the medial border of the forearm and hand. * **Nerve involved in Winging of Scapula:** Long thoracic nerve (C5, C6, C7).

Q: Which of the following nerves is most commonly damaged during a wrist slash injury?

Median nerve. **Explanation:** In a wrist slash injury (often seen in suicidal attempts or accidental trauma), the **Median nerve** is the most commonly injured nerve. This is due to its relatively superficial anatomical position at the level of the wrist, where it lies just deep to the palmaris longus tendon and between the flexor carpi radialis and flexor digitorum superficialis. **Why the other options are incorrect:** * **Ulnar nerve:** While frequently injured in deep lacerations, it is situated more medially and is partially protected by the flexor carpi ulnaris tendon and the pisiform bone. * **Radial nerve:** The main trunk of the radial nerve does not cross the volar (palmar) aspect of the wrist. Only its superficial sensory branch is present laterally, but it is less frequently the primary nerve involved in transverse slash injuries compared to the median nerve. * **Palmar cutaneous branch of the median nerve:** This branch arises proximal to the wrist and stays superficial to the flexor retinaculum. While it can be damaged, the question asks for the nerve most commonly damaged; the main trunk of the median nerve is the standard clinical answer for these injuries. **NEET-PG High-Yield Pearls:** * **Clinical Presentation:** Injury at the wrist (low median nerve palsy) leads to **"Ape Thumb Deformity"** due to paralysis of the thenar muscles (Opponens pollicis, Abductor pollicis brevis, and Flexor pollicis brevis). * **Sensory Loss:** Occurs over the lateral 3.5 fingers. * **The "Million Dollar Nerve":** The recurrent motor branch of the median nerve is often called this because its injury results in the loss of thumb opposition, a major disability. * **Test of Choice:** The **Pen Test** (testing Abductor Pollicis Brevis) is used to assess motor function of the median nerve at the thumb.

Q: All of the following muscles undergo paralysis after injury to C5 and C6 spinal nerves EXCEPT?

Coracobrachialis. **Explanation:** The question tests your knowledge of the **Brachial Plexus** and the specific root values of the muscles of the upper limb. Injury to the **C5 and C6** nerve roots is clinically known as **Erb’s Palsy**. **1. Why Coracobrachialis is the Correct Answer:** While the Coracobrachialis is located in the anterior compartment of the arm and is supplied by the **Musculocutaneous nerve**, its primary nerve root value is **C6 and C7** (some texts cite C5, C6, C7, but C7 is the dominant contributor). Because it receives significant innervation from the C7 root, it is generally spared or only partially weakened in a pure C5-C6 injury, unlike the other muscles listed which are predominantly C5-C6 dependent. **2. Analysis of Incorrect Options:** * **Biceps Brachii:** Supplied by the Musculocutaneous nerve with root values **C5 and C6**. It is completely paralyzed in Erb’s Palsy. * **Brachialis:** Also supplied by the Musculocutaneous nerve (**C5, C6**). It is the primary flexor of the elbow and is paralyzed. * **Brachioradialis:** Although located in the forearm, it is supplied by the Radial nerve with root values **C5 and C6**. It is a classic muscle lost in high trunk/root injuries. **3. Clinical Pearls for NEET-PG:** * **Erb’s Palsy (Upper Trunk Injury):** Results in the "Policeman’s tip" or "Waiter’s tip" deformity. The arm is adducted (loss of abductors), medially rotated (loss of lateral rotators), and the forearm is extended (loss of biceps/brachialis) and pronated (loss of supinator). * **Muscles affected in Erb's:** Supraspinatus, Infraspinatus, Deltoid, Biceps, Brachialis, and Brachioradialis. * **High-Yield Tip:** If a question asks for the "most characteristic" muscle spared in Musculocutaneous nerve lesions (but not necessarily root lesions), look for the Coracobrachialis as the nerve often pierces it before supplying the rest.

Q: A 25-year-old male athlete is admitted to the emergency department after a bad landing in the pole vault. Radiographic examination of his hand reveals a fractured carpal bone in the floor of the anatomic snuffbox. Which bone has most likely been fractured?

Scaphoid. ### Explanation **Correct Option: B. Scaphoid** The **anatomic snuffbox** is a triangular depression on the radial aspect of the wrist. Its floor is formed primarily by the **scaphoid** bone (and to a lesser extent, the trapezium). The scaphoid is the most frequently fractured carpal bone [1], typically occurring due to a fall on an outstretched hand (FOOSH). Tenderness localized within the snuffbox is a classic clinical sign of a scaphoid fracture. **Analysis of Incorrect Options:** * **A. Triquetral:** This bone is located on the ulnar side of the wrist (medial aspect) and does not contribute to the floor of the snuffbox. * **C. Capitate:** This is the largest carpal bone, located centrally in the distal row. It lies deep and medial to the snuffbox. * **D. Hamate:** This bone is located on the ulnar side of the distal row, characterized by its hook (uncinate process). It is far from the radial-sided snuffbox. **Clinical Pearls for NEET-PG:** * **Boundaries of Snuffbox:** Lateral (Anterior) – Tendons of Abductor pollicis longus and Extensor pollicis brevis; Medial (Posterior) – Tendon of Extensor pollicis longus. * **Contents:** The **Radial artery** passes through the snuffbox to reach the first dorsal metacarpal space. * **Blood Supply & Complications:** The scaphoid receives its blood supply from the radial artery via its **distal pole**. Therefore, a fracture at the waist can lead to **avascular necrosis (AVN)** of the proximal pole and non-union. * **Radiology:** Scaphoid fractures may not be visible on initial X-rays; if clinical suspicion is high, the wrist should be immobilized and re-imaged in 10-14 days [1].

Q: The pisiform bone articulates with which carpal bone?

Triquetral. The **pisiform** is a unique carpal bone located in the proximal row. It is classified as a **sesamoid bone** because it develops within the tendon of the **flexor carpi ulnaris (FCU)** muscle. **Why Triquetral is Correct:** The pisiform is situated on the palmar surface of the **triquetral** bone. It articulates solely with the anterior (palmar) surface of the triquetrum via a flat, circular facet. Unlike other carpal bones, the pisiform does not participate in the radiocarpal (wrist) joint or the midcarpal joint; its primary function is to act as a pulley for the FCU, increasing its mechanical advantage. **Why Other Options are Incorrect:** * **Scaphoid:** Located on the lateral (radial) side of the proximal row; it articulates with the radius, lunate, capitate, trapezium, and trapezoid. * **Trapezium:** A distal row bone that articulates with the scaphoid and the first metacarpal (forming the saddle-shaped CMC joint of the thumb). * **Lunate:** Located in the center of the proximal row; it articulates with the radius, scaphoid, triquetral, capitate, and hamate. **High-Yield Clinical Pearls for NEET-PG:** * **Ossification:** The pisiform is the **last carpal bone to ossify** (usually between ages 9–12 years). * **Guyon’s Canal:** The pisiform forms the medial boundary of the ulnar canal (Guyon’s canal), which transmits the ulnar nerve and artery into the hand [1]. * **Attachments:** It serves as an attachment point for the **pisohamate ligament**, **piso-metacarpal ligament**, and the **abductor digiti minimi** [1]. * **Palpation:** It is the most easily palpable carpal bone on the ulnar aspect of the wrist crease.

Question 1

The lateral antebrachial cutaneous nerve originates from which nerve?

Accepted Answer

Musculocutaneous nerve

Answer

Axillary nerve

Answer

Medial cord nerve

Answer

Radial nerve

Question 2

Enumerate the two structures passing through the quadrangular space of the back.

Accepted Answer

Posterior circumflex humeral artery and Axillary nerve.

Answer

Suprascapular artery and Axillary nerve.

Answer

Subscapular artery and Radial nerve.

Answer

Profunda brachii artery and Radial nerve.

Question 3

A suspect is brought in after sustaining a gunshot wound to the arm, resulting in damage to the median nerve. Which of the following symptoms is likely produced by this nerve damage?

Accepted Answer

Ape hand

Answer

Waiter's tip hand

Answer

Claw hand

Answer

Wrist drop

Question 4

All of the following are true about the clavicle, except:

Accepted Answer

No treatment required for fracture but rest

Answer

Breaks at the midpoint

Answer

First bone to ossify

Answer

Ossifies in membrane

Question 5

Several deficits in muscle function of the right upper limb were noted, including inability to abduct the arm. This was caused by denervation of which muscle?

Accepted Answer

Deltoid

Answer

Infraspinatus

Answer

Latissimus dorsi

Answer

Teres minor

Question 6

Which of the following statements regarding brachial plexus injuries is NOT true?

Accepted Answer

Erb's palsy involves injury to C5, C6, C7 roots.

Answer

Klumpke's palsy involves injury to C8, T1 roots.

Answer

Brachial plexus injury with Horner's syndrome is seen with injury to T1.

Answer

Erb's palsy deformity is also known as the 'waiter's tip' or 'policeman's hand' deformity.

Question 7

Which of the following nerves is most commonly damaged during a wrist slash injury?

Accepted Answer

Median nerve

Answer

Ulnar nerve

Answer

Radial nerve

Answer

Median nerve - palmar cutaneous branch

Question 8

All of the following muscles undergo paralysis after injury to C5 and C6 spinal nerves EXCEPT?

Accepted Answer

Coracobrachialis

Answer

Biceps brachii

Answer

Brachialis

Answer

Brachioradialis

Question 9

A 25-year-old male athlete is admitted to the emergency department after a bad landing in the pole vault. Radiographic examination of his hand reveals a fractured carpal bone in the floor of the anatomic snuffbox. Which bone has most likely been fractured?

Accepted Answer

Scaphoid

Answer

Triquetral

Answer

Capitate

Answer

Hamate

Question 10

The pisiform bone articulates with which carpal bone?

Accepted Answer

Triquetral

Answer

Scaphoid

Answer

Trapezium

Answer

Lunate

Upper Limb — MCQs

Upper Limb — MCQs

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