Upper Limb Practice Questions

Q: Which of the following muscles does not have a dual nerve supply?

Abductor pollicis brevis. In anatomy, muscles with a **dual nerve supply** (hybrid muscles) are high-yield topics for NEET-PG. These muscles are typically located at the transition zones between different nerve territories. ### **Why Abductor Pollicis Brevis (APB) is the Correct Answer** The **Abductor Pollicis Brevis** is a pure thenar muscle. It is supplied **exclusively by the Recurrent branch of the Median Nerve (C8, T1)** [2]. Unlike some other muscles of the thumb or forearm, it does not receive any contribution from the ulnar nerve. ### **Analysis of Incorrect Options (Hybrid Muscles)** * **Flexor Pollicis Brevis (FPB):** This is a classic hybrid muscle [3]. The superficial head is supplied by the **Median nerve**, while the deep head is supplied by the **Deep branch of the Ulnar nerve**. * **Flexor Digitorum Profundus (FDP):** This muscle has a dual supply based on its digits [3]. The lateral half (index and middle fingers) is supplied by the **Anterior Interosseous Nerve (Median)**, while the medial half (ring and little fingers) is supplied by the **Ulnar nerve**. * **Pectoralis Major:** It receives a dual supply from both the **Medial and Lateral Pectoral nerves**, arising from the medial and lateral cords of the brachial plexus, respectively [1]. ### **High-Yield Clinical Pearls for NEET-PG** * **Other Hybrid Muscles of the Upper Limb:** Brachialis (Musculocutaneous and Radial) and Adductor Magnus (Obturator and Sciatic - in the lower limb). * **The "Million Dollar Nerve":** The recurrent branch of the median nerve (supplying APB) is superficial and prone to injury in carpal tunnel release [2]. * **Ape Thumb Deformity:** Results from median nerve palsy affecting the thenar muscles, primarily the APB, leading to an inability to abduct the thumb away from the palm.

Q: All of the following muscles are innervated by branches from the brachial plexus except?

Trapezius. The correct answer is **Trapezius** because it is the only muscle listed that does not receive its motor innervation from the brachial plexus. ### 1. Why Trapezius is the Correct Answer The Trapezius is a muscle of the neck and back that is embryologically derived from the branchial arches rather than the limb buds. Its motor supply is provided by the **Spinal Accessory Nerve (Cranial Nerve XI)**. Its sensory (proprioceptive) fibers come from the ventral rami of **C3 and C4**. Since the brachial plexus is formed by the ventral rami of C5–T1, the Trapezius falls outside its distribution. ### 2. Analysis of Incorrect Options * **Supraspinatus:** Innervated by the **Suprascapular nerve**, which arises from the **Upper Trunk** of the brachial plexus (C5, C6). * **Latissimus dorsi:** Innervated by the **Thoracodorsal nerve** (nerve to latissimus dorsi), which arises from the **Posterior Cord** of the brachial plexus (C6, C7, C8). * **Rhomboid major:** Innervated by the **Dorsal Scapular nerve**, which arises directly from the **Root of C5** of the brachial plexus. ### 3. NEET-PG High-Yield Pearls * **The "Exception" Rule:** Most muscles of the upper limb and those connecting the limb to the axial skeleton are supplied by the brachial plexus, *except* the Trapezius (CN XI) and the Levator Scapulae (which receives additional direct branches from C3/C4). * **Clinical Correlation:** Injury to the Spinal Accessory Nerve results in "drooping of the shoulder" and an inability to shrug, but does not affect the nerve supply to the rotator cuff. * **Roots vs. Trunks:** Remember that the **Dorsal Scapular Nerve** and **Long Thoracic Nerve** are the only two branches that arise directly from the **Roots** of the plexus.

Q: Erb's point is formed by which cervical nerve roots?

C5 and C6. **Explanation:** **Erb’s point** is a specific anatomical location in the upper part of the brachial plexus where **six nerves meet**. It is primarily formed by the union of the **C5 and C6 nerve roots**, which together constitute the **Upper Trunk** of the brachial plexus. At this junction, the following six nerves converge or diverge: 1. **C5 root** 2. **C6 root** 3. **Suprascapular nerve** 4. **Nerve to subclavius** 5. **Anterior division** of the upper trunk 6. **Posterior division** of the upper trunk **Analysis of Options:** * **Option B (C5 and C6):** Correct. These roots form the upper trunk, the site of Erb's point. * **Option A (C4 and C5):** Incorrect. While C4 may contribute a small branch to the plexus (pre-fixed plexus), it is not the primary constituent of Erb’s point. * **Option C (C6 and C7):** Incorrect. C7 continues as the Middle Trunk. * **Option D (C6 and T1):** Incorrect. T1 joins C8 to form the Lower Trunk. **Clinical Pearls for NEET-PG:** * **Erb’s Palsy:** Caused by an injury to the upper trunk (C5-C6) due to a sudden increase in the angle between the neck and shoulder (e.g., birth trauma or falling on the shoulder). * **Deformity:** Characterized by the **"Policeman’s tip"** or **"Waiter’s tip"** hand. * **Muscle Involvement:** Primarily affects the Deltoid, Biceps brachii, Brachialis, and Brachioradialis. * **Clinical Presentation:** The arm hangs by the side, is **adducted** and **medially rotated**, with the forearm **extended** and **pronated**. Loss of sensation occurs over the lateral aspect of the arm (deltoid region).

Q: Which artery lies in Guyon's canal?

Ulnar artery. Explanation: Guyon’s Canal (Ulnar Canal) is a fibro-osseous tunnel located on the medial side of the wrist. It serves as a critical anatomical passage for the ulnar nerve and the ulnar artery as they enter the hand from the forearm [1]. * Why Option A is correct: The ulnar artery, accompanied by the ulnar nerve, passes superficial to the flexor retinaculum but deep to the palmar carpal ligament (volar carpal ligament) and the palmaris brevis muscle [1]. Within the canal, the artery typically lies lateral to the ulnar nerve. * Why other options are incorrect: * Radial artery: Passes through the Anatomical Snuffbox on the lateral (radial) aspect of the wrist to reach the dorsum of the hand [1]. * Brachial artery: Terminates in the cubital fossa (at the level of the neck of the radius) by dividing into the radial and ulnar arteries. * Subclavian artery: Located in the root of the neck; it becomes the axillary artery at the outer border of the first rib. High-Yield Clinical Pearls for NEET-PG: * Boundaries of Guyon’s Canal: Medial wall (Pisiform), Lateral wall (Hook of Hamate), Roof (Palmar carpal ligament), Floor (Flexor retinaculum) [1]. * Guyon’s Canal Syndrome: Compression of the ulnar nerve here (often by ganglion cysts or handlebar palsy in cyclists) leads to sensory loss in the medial 1.5 fingers and motor weakness of intrinsic hand muscles, but spares the palmar cutaneous branch (no sensory loss on the proximal palm) [1]. * Key Distinction: Unlike the median nerve in the carpal tunnel, the ulnar nerve and artery pass superficial to the flexor retinaculum [1].

Q: What is the lymphatic drainage of the upper outer quadrant of the breast?

Anterior axillary nodes. **Explanation:** The lymphatic drainage of the breast is a high-yield topic for NEET-PG, as approximately **75% of the lymph** from the breast drains into the **axillary lymph nodes** [1]. 1. **Why Anterior Axillary Nodes are Correct:** The axillary lymph nodes are divided into five groups. The **Anterior (Pectoral) group** lies along the lower border of the pectoralis minor, following the lateral thoracic artery. This group specifically receives the bulk of the lymph from the **upper outer quadrant** and the lateral half of the breast. Since the upper outer quadrant contains the most glandular tissue (and the axillary tail of Spence), it is the most common site for breast carcinoma and its primary drainage is to these nodes. 2. **Why Other Options are Incorrect:** * **Posterior Axillary Nodes:** These lie along the subscapular vessels and primarily drain the posterior thoracic wall and the scapular region, not the breast. * **Paratracheal Nodes:** These are located in the neck/thorax along the trachea. They are not involved in primary breast drainage. (Note: The medial quadrants drain into **Internal Mammary/Parasternal nodes**). * **Apical Nodes:** While the apical nodes do receive lymph from the breast, they represent a **secondary level** of drainage. Lymph typically passes through the anterior or central nodes before reaching the apical group (Level III) [1]. **Clinical Pearls for NEET-PG:** * **Sentinel Node:** The first node to receive drainage from a tumor; usually found in the anterior axillary group. * **Berg’s Levels:** Axillary nodes are classified by their relation to the **Pectoralis minor**: Level I (Lateral), Level II (Posterior/Deep), Level III (Medial/Apical) [1]. * **Internal Mammary Nodes:** Drain ~20-25% of lymph, primarily from the medial quadrants; this is a common route for contralateral metastasis [2].

Q: Which muscle in the extensor compartment of the forearm causes flexion of the elbow?

Brachioradialis. The **Brachioradialis** is a unique muscle of the forearm. While it is anatomically located in the superficial layer of the posterior (extensor) compartment and is innervated by the **Radial nerve**, its primary physiological function is **flexion of the elbow**, especially when the forearm is in a mid-prone position. **Why Brachioradialis is correct:** Most muscles in the extensor compartment originate from the lateral epicondyle and act on the wrist or fingers. However, the Brachioradialis originates higher up on the **lateral supracondylar ridge** of the humerus and inserts into the distal radius. Because its bulk lies anterior to the elbow joint axis, it acts as a powerful flexor rather than an extensor. **Analysis of Incorrect Options:** * **Abductor pollicis longus (B):** A deep layer muscle of the posterior compartment [1]. Its primary action is abduction and extension of the thumb at the CMC joint [1]. * **Extensor pollicis longus (C):** A deep layer muscle that extends the terminal phalanx of the thumb [1]. * **Extensor carpi radialis longus (D):** While it also originates from the supracondylar ridge and is a "hybrid" muscle, its primary action is extension and abduction (radial deviation) of the **wrist**, not flexion of the elbow [1]. **High-Yield NEET-PG Pearls:** * **The "Shunting" Muscle:** Brachioradialis acts as a shunt muscle, providing stability to the elbow joint during rapid flexion and extension. * **Innervation Paradox:** It is one of the few muscles supplied by the Radial nerve (C5, C6) that is a flexor. * **Testing:** It is best tested by flexing the elbow against resistance in the **mid-prone position** (the "hammering" position). * **Reflex:** The Brachioradialis reflex tests the **C6** spinal nerve root.

Q: What is the nerve supply of the Teres major muscle?

Lower subscapular nerve. The **Teres major** muscle is an important muscle of the scapular region, often referred to as the "Latissimus dorsi's little helper" because it shares the same actions (adduction, extension, and medial rotation of the humerus). [1] ### 1. Why the Correct Answer is Right The **Lower subscapular nerve (C5, C6)** arises from the posterior cord of the brachial plexus. It supplies two muscles: the **Subscapularis** (lower fibers) and the **Teres major**. It is essential to remember that while the upper subscapular nerve only supplies the subscapularis, the lower subscapular nerve has a dual distribution. ### 2. Why the Other Options are Wrong * **Suprascapular nerve (C5, C6):** This nerve arises from the upper trunk of the brachial plexus and supplies the **Supraspinatus** and **Infraspinatus** muscles. * **Axillary nerve (C5, C6):** This nerve supplies the **Deltoid** and the **Teres minor**. A common point of confusion in exams is distinguishing between Teres major (Lower subscapular n.) and Teres minor (Axillary n.). * **Upper subscapular nerve (C5, C6):** This nerve supplies only the upper portion of the **Subscapularis** muscle. ### 3. NEET-PG High-Yield Pearls * **The "Lats' Little Helper":** Teres major inserts into the **medial lip** of the bicipital groove of the humerus (Latissimus dorsi inserts into the floor). * **Quadrangular Space:** The Teres major forms the **inferior boundary** of the quadrangular space (the superior boundary is the Teres minor). * **Nerve Mnemonic:** Remember that the **Axillary nerve** supplies the "Minor" (Teres minor), while the **Lower Subscapular nerve** supplies the "Major" (Teres major). * **Posterior Cord Branches:** Remember the mnemonic **STAR** (Subscapular [Upper & Lower], Thoracodorsal, Axillary, Radial).

Q: Which muscle crosses the shoulder joint?

Biceps long head. ### Explanation The shoulder joint (glenohumeral joint) is crossed by several muscles, but the **Long Head of the Biceps Brachii** is unique due to its **intracapsular but extrasynovial** course. **1. Why Biceps Long Head is the Correct Answer:** The long head of the biceps originates from the **supraglenoid tubercle** of the scapula. Its tendon passes directly through the glenohumeral joint cavity, over the head of the humerus, and exits the joint through the bicipital groove. Because it resides within the joint capsule, it plays a critical role in stabilizing the humeral head against the glenoid cavity during arm movements. **2. Analysis of Other Options:** * **Biceps Short Head:** Originates from the **coracoid process** (extra-articular). While it acts on the shoulder joint as a weak flexor, it does not "cross" or pass through the joint cavity like the long head. * **Triceps Long Head:** Originates from the **infraglenoid tubercle**. While it technically crosses the joint inferiorly to reach the olecranon, in the context of standard anatomy questions regarding "crossing the joint" (specifically referring to the intracapsular course), the Biceps Long Head is the classic and most significant answer. * **Coracobrachialis:** Originates from the coracoid process and inserts into the humerus. It is a stabilizer and flexor but remains entirely extracapsular. **3. High-Yield Clinical Pearls for NEET-PG:** * **Transverse Humeral Ligament:** This ligament holds the long head of the biceps tendon in the bicipital groove. * **SLAP Lesion:** (Superior Labrum Anterior to Posterior) involves a tear where the long head of the biceps tendon attaches to the glenoid labrum. * **Popeye Deformity:** Occurs due to a rupture of the long head of the biceps tendon, causing the muscle belly to bunch up in the distal arm.

Q: Weakness of which muscle would result in the following type of lesion?

Serratus Anterior. ***Serratus Anterior*** - Weakness of the **serratus anterior** causes **winged scapula**, where the medial border of the scapula protrudes posteriorly when pushing against a wall or doing push-ups. - Innervated by the **long thoracic nerve of Bell** (C5-C7), and its paralysis prevents proper **protraction and stabilization** of the scapula against the chest wall. *Deltoid* - Weakness results in inability to **abduct the arm** beyond the first 15 degrees and difficulty with shoulder flexion and extension. - Innervated by the **axillary nerve**; weakness does not cause scapular winging but rather **deltoid atrophy** and loss of shoulder contour. *Pectoralis major* - Weakness causes difficulty with **adduction, flexion, and internal rotation** of the arm, particularly when pushing or pressing movements. - Innervated by **medial and lateral pectoral nerves**; weakness results in **loss of anterior axillary fold** but does not affect scapular positioning. *Infraspinatus* - Weakness impairs **external rotation** of the arm and contributes to **rotator cuff dysfunction** with potential shoulder instability. - Innervated by the **suprascapular nerve**; weakness causes difficulty with **external rotation** but does not produce scapular winging.

Q: Which of the following muscles is responsible for shrugging the shoulders?

Trapezius. **Explanation:** The **Trapezius** is the correct answer because its **upper fibers** are primarily responsible for the elevation of the scapula, a movement clinically known as "shrugging the shoulders." It is a large, superficial muscle of the back that acts on the pectoral girdle. **Why the other options are incorrect:** * **Rhomboid minor:** While it helps in the elevation and retraction of the scapula, its primary role is to square the shoulders and stabilize the scapula against the thoracic wall. It is not the prime mover for shrugging. * **Serratus anterior:** Known as the "boxer’s muscle," it is responsible for **protraction** of the scapula and holds the medial border of the scapula against the rib cage. Paralysis of this muscle leads to "winging of scapula." * **Latissimus dorsi:** Known as the "climbing muscle," it performs adduction, extension, and medial rotation of the humerus. It actually acts to **depress** the shoulder rather than elevate it. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Supply:** The Trapezius is unique as it is supplied by the **Spinal Accessory Nerve (CN XI)** for motor function and C3-C4 spinal nerves for proprioception. * **Testing:** To test the Spinal Accessory Nerve, the patient is asked to shrug their shoulders against resistance. * **Overhead Abduction:** The Trapezius (upper and lower fibers) works with the Serratus anterior to rotate the scapula upward, allowing for abduction of the arm beyond 90 degrees.

Question 1

Which of the following muscles does not have a dual nerve supply?

Accepted Answer

Abductor pollicis brevis

Answer

Flexor pollicis brevis

Answer

Flexor digitorum profundus

Answer

Pectoralis major

Question 2

All of the following muscles are innervated by branches from the brachial plexus except?

Accepted Answer

Trapezius

Answer

supraspinatus

Answer

Latissimus dorsi

Answer

Rhomboid major

Question 3

Erb's point is formed by which cervical nerve roots?

Accepted Answer

C5 and C6

Answer

C4 and C5

Answer

C6 and C7

Answer

C6 and T1

Question 4

Which artery lies in Guyon's canal?

Accepted Answer

Ulnar artery

Answer

Radial artery

Answer

Brachial artery

Answer

Subclavian artery

Question 5

What is the lymphatic drainage of the upper outer quadrant of the breast?

Accepted Answer

Anterior axillary nodes

Answer

Posterior axillary nodes

Answer

Paratracheal nodes

Answer

Apical nodes

Question 6

Which muscle in the extensor compartment of the forearm causes flexion of the elbow?

Accepted Answer

Brachioradialis

Answer

Abductor pollicis longus

Answer

Extensor pollicis longus

Answer

Extensor carpi radialis longus

Question 7

What is the nerve supply of the Teres major muscle?

Accepted Answer

Lower subscapular nerve

Answer

Suprascapular nerve

Answer

Axillary nerve

Answer

Upper subscapular nerve

Question 8

Which muscle crosses the shoulder joint?

Accepted Answer

Biceps long head

Answer

Biceps short head

Answer

Triceps long head

Answer

Coracobrachialis

Question 9

Weakness of which muscle would result in the following type of lesion?

Accepted Answer

Serratus Anterior

Answer

Deltoid

Answer

Pectoralis major

Answer

Infraspinatus

Question 10

Which of the following muscles is responsible for shrugging the shoulders?

Accepted Answer

Trapezius

Answer

Rhomboid minor

Answer

Serratus anterior

Answer

Latissimus dorsi

Upper Limb — MCQs

Upper Limb — MCQs

On this page

Practice by Chapter

Want unlimited practice?