Upper Limb Practice Questions

Q: Which of the following muscles can be congenitally absent?

Pectoralis major. Explanation: The **Pectoralis major** is the most common muscle of the upper limb to be congenitally absent. This condition is often associated with **Poland Syndrome**, a rare congenital anomaly characterized by the unilateral absence of the sternocostal head of the pectoralis major, often accompanied by syndactyly (fused fingers) and hypoplasia of the breast or nipple on the affected side. **Analysis of Options:** * **Pectoralis major (Correct):** While the muscle is essential for powerful adduction and medial rotation of the humerus, its absence is a well-documented clinical entity. It is a high-yield topic in anatomy and surgery. * **Teres minor:** This is a stable component of the rotator cuff. While variations in its nerve supply exist, its congenital absence is extremely rare and not a standard clinical association. * **Semimembranosus:** This is a vital hamstring muscle. Its absence would severely impair knee flexion and hip extension; it is not typically noted for congenital absence. * **Palmaris brevis:** This is a small, subcutaneous muscle in the palm. While the **Palmaris longus** is frequently absent (about 15% of the population), the Palmaris brevis is generally present. **High-Yield Clinical Pearls for NEET-PG:** * **Poland Syndrome:** Look for keywords like "absent anterior axillary fold," "chest wall depression," and "syndactyly." * **Palmaris Longus:** Do not confuse it with Palmaris brevis. Palmaris longus is the most common muscle to be absent in the *entire body* (phylogenetically retrogressing). * **Other muscles prone to absence:** Pyramidalis (20%), Plantaris (10%), and Peroneus tertius.

Q: Which of the following is a modification of deep fascia?

Extensor retinaculum. The **deep fascia** is a dense, inelastic connective tissue membrane that invests muscles and structures throughout the body. In the limbs, it undergoes specific structural modifications to serve functional purposes. **1. Why Extensor Retinaculum is correct:** A **retinaculum** is a localized thickening of the deep fascia that acts as a "tie-beam" or pulley. Its primary function is to hold tendons in place during joint movement, preventing them from "bowing" (bowstringing). The extensor retinaculum of the wrist is a classic example of this modification, converting the grooves on the posterior aspect of the radius and ulna into osteofibrous tunnels for the extensor tendons. **2. Why the other options are incorrect:** * **Palmar and Plantar Aponeuroses:** While these are dense fibrous structures, they are technically considered **modifications of the deep fascia of the palm/sole** that have thickened to protect underlying neurovascular structures and provide firm attachment for the skin. However, in the context of standard anatomical classification for NEET-PG, retinacula are the quintessential examples of "thickened deep fascia" acting as pulleys. * **Fibrous Flexor Sheath:** This is a specialized tubular tunnel formed by the deep fascia and the periosteum of the phalanges. While related to deep fascia, it is a more complex osteofibrous arrangement rather than a simple fascial thickening like a retinaculum. **High-Yield Clinical Pearls for NEET-PG:** * **Retinacula Function:** They prevent "bowstringing" of tendons. * **Extensor Retinaculum:** Attached laterally to the radius and medially to the triquetral and pisiform bones. It forms **6 compartments** for extensor tendons. * **Iliotibial Tract (IT Band):** Another high-yield modification of deep fascia (fascia lata) in the lower limb. * **Axillary Sheath:** A modification of the prevertebral layer of deep cervical fascia.

Q: Which nerve is involved in ape thumb deformity?

Median. **Explanation:** **Ape Thumb Deformity** (also known as Simian Hand) is a characteristic clinical feature of **Median Nerve** injury, typically occurring at the wrist (e.g., Carpal Tunnel Syndrome or distal lacerations) [1]. **Why Median Nerve is correct:** The Median nerve supplies the **Thenar muscles** (Abductor Pollicis Brevis, Flexor Pollicis Brevis, and Opponens Pollicis). Paralysis of these muscles leads to: 1. **Loss of Opposition:** The thumb cannot be brought across the palm. 2. **Loss of Abduction:** The thumb 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 gives the hand a flattened, "ape-like" appearance. **Why other options are incorrect:** * **Radial Nerve:** Injury leads to **Wrist Drop** due to paralysis of the extensors [1]. It does not affect the thenar eminence. * **Ulnar Nerve:** Injury leads to **Claw Hand** (Main en Griffe) due to paralysis of the lumbricals and interossei. It also causes "Froment’s Sign" due to Adductor Pollicis paralysis. * **Axillary Nerve:** Injury leads to paralysis of the Deltoid and Teres Minor, resulting in loss of shoulder abduction and "flat shoulder" appearance. **High-Yield Clinical Pearls for NEET-PG:** * **Pointy Index (Benedict’s Sign):** Seen in high median nerve palsy when attempting to make a fist. * **Kiloh-Nevin Syndrome:** Involvement of the Anterior Interosseous Nerve (branch of Median); patient cannot make an "OK" sign. * **Mnemonic:** Median nerve is the "Laborer’s nerve" (precision/thumb work), while Ulnar nerve is the "Musician’s nerve" (fine finger movements).

Q: While carrying a heavy suitcase, the downward dislocation of the glenohumeral joint is resisted by which of the following muscles EXCEPT?

Latissimus dorsi. Explanation: The stability of the glenohumeral joint depends on both static and dynamic stabilizers. When carrying a heavy weight (like a suitcase), the primary force acting on the shoulder is a **downward vertical pull**, which threatens to dislocate the humeral head inferiorly. **Why Latissimus dorsi is the correct answer:** The **Latissimus dorsi** is a large, powerful muscle that originates from the trunk and inserts into the floor of the bicipital groove. Its primary actions are adduction, internal rotation, and extension of the humerus. Because its insertion point is relatively low and its pull is directed downwards and backwards, it does **not** resist downward dislocation; in fact, it can contribute to the downward pull on the humerus. **Why the other options are incorrect:** The muscles that resist downward dislocation are those with a **vertical or near-vertical orientation** that cross the joint from the acromion/coracoid process to the humerus: * **Deltoid (A):** The multipennate fibers (especially the middle part) provide a strong upward pull, acting as a primary dynamic stabilizer against gravity. * **Coracobrachialis (B) & Short head of biceps (C):** Both muscles originate from the coracoid process and insert distally on the humerus and radius, respectively. Their vertical orientation allows them to act as "shunts," pulling the humeral head upwards into the glenoid cavity when a heavy load is carried. **High-Yield Clinical Pearls for NEET-PG:** * **Static Stabilizers:** The most important static stabilizer against downward dislocation in the *adducted* position is the **Superior Glenohumeral Ligament (SGHL)** and the **Coracohumeral ligament**. * **Rotator Cuff:** While the Supraspinatus prevents downward displacement, the Subscapularis and Infraspinatus primarily provide horizontal stability. * **Nerve Injury:** The Axillary nerve is most at risk during inferior (downward) dislocations of the shoulder.

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: 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: 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: A 22-year-old woman is admitted to the emergency department in an unconscious state. The nurse takes a radial pulse to determine the heart rate of the patient. This pulse is felt lateral to which tendon?

Flexor carpi radialis. The radial pulse is a fundamental clinical assessment point in the upper limb. To locate it, the clinician palpates the **radial artery** against the distal end of the radius. **1. Why Flexor Carpi Radialis (FCR) is correct:** At the wrist, the radial artery lies superficially in the "radial pulse point." Its precise anatomical relation is **lateral to the tendon of the Flexor Carpi Radialis** and medial to the tendon of the Brachioradialis [1]. Because the artery lies directly over the flat distal surface of the radius, it can be easily compressed against the bone to feel the pulsation. **2. Why the other options are incorrect:** * **Palmaris longus:** This tendon is located medial to the FCR. It is often used as a landmark for the median nerve, which lies deep or slightly lateral to it [1]. * **Flexor pollicis longus:** This is a deep muscle of the forearm. Its tendon lies deep in the carpal tunnel and is not a superficial landmark for pulse palpation. * **Flexor digitorum profundus:** This is the deepest muscle of the anterior compartment; its tendons are situated deep to the flexor digitorum superficialis and are not palpable landmarks for the radial artery. **Clinical Pearls for NEET-PG:** * **Allen’s Test:** Used to assess the patency of the radial and ulnar arteries (collateral circulation) before performing arterial blood gas (ABG) sampling. * **Anatomical Snuffbox:** The radial artery also passes through the floor of the anatomical snuffbox before piercing the first dorsal interosseous muscle. * **Median Nerve Relation:** The median nerve lies between the tendons of the Palmaris longus and Flexor carpi radialis at the wrist [1].

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: 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.

Question 1

Which of the following muscles can be congenitally absent?

Accepted Answer

Pectoralis major

Answer

Teres minor

Answer

Semimembranosus

Answer

Palmaris brevis

Question 2

Which of the following is a modification of deep fascia?

Accepted Answer

Extensor retinaculum

Answer

Palmar aponeurosis

Answer

Fibrous flexor sheath

Answer

Plantar aponeurosis

Question 3

Which nerve is involved in ape thumb deformity?

Accepted Answer

Median

Answer

Radial

Answer

Ulnar

Answer

Axillary

Question 4

While carrying a heavy suitcase, the downward dislocation of the glenohumeral joint is resisted by which of the following muscles EXCEPT?

Accepted Answer

Latissimus dorsi

Answer

Deltoid

Answer

Coracobrachialis

Answer

Short head of biceps

Question 5

The lateral antebrachial cutaneous nerve originates from which nerve?

Accepted Answer

Musculocutaneous nerve

Answer

Axillary nerve

Answer

Medial cord nerve

Answer

Radial nerve

Question 6

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 7

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 8

A 22-year-old woman is admitted to the emergency department in an unconscious state. The nurse takes a radial pulse to determine the heart rate of the patient. This pulse is felt lateral to which tendon?

Accepted Answer

Flexor carpi radialis

Answer

Palmaris longus

Answer

Flexor pollicis longus

Answer

Flexor digitorum profundus

Question 9

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 10

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

Upper Limb — MCQs

Upper Limb — MCQs

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