Upper Limb Practice Questions

Q: Which of the following muscles is known as the 'climber's muscle'?

Latissimus dorsi. **Explanation:** The **Latissimus dorsi** is famously known as the **'climber’s muscle'** because of its powerful actions on the humerus. To pull the trunk upward and forward during climbing or swimming, the muscle performs three primary movements: **adduction, extension, and medial rotation** of the arm. When the arms are fixed (as when gripping a rock or ledge), the Latissimus dorsi acts to pull the trunk toward the arms, a mechanism essential for climbing. **Analysis of Options:** * **A. Serratus anterior:** Known as the **'boxer’s muscle'**, it is responsible for the protraction of the scapula and keeps the medial border of the scapula opposed to the thoracic wall. * **C. Rhomboidus major:** This muscle acts to retract (adduct) and rotate the scapula to depress the glenoid cavity. It does not provide the power stroke required for climbing. * **D. Subscapularis:** A member of the rotator cuff (SITS) muscles, its primary role is the internal rotation of the humerus and stabilization of the shoulder joint. **High-Yield Clinical Pearls for NEET-PG:** * **Nerve Supply:** It is supplied by the **Thoracodorsal nerve** (C6, C7, C8), a branch of the posterior cord of the brachial plexus [1]. * **Surgical Significance:** The Latissimus dorsi flap is commonly used in reconstructive surgeries, particularly for breast reconstruction. * **Triangle of Auscultation:** The superior horizontal border of the Latissimus dorsi forms the inferior boundary of this triangle, where breath sounds are most clearly heard.

Q: What forms the roof of the anatomical snuff box?

Superficial branch of the radial nerve. ### Explanation The **anatomical snuff box** is a triangular depression on the lateral aspect of the wrist, visible during thumb extension. To answer questions regarding its anatomy, it is crucial to distinguish between the boundaries (walls), the floor, and the roof (superficial structures). [1] **1. Why Option C is Correct:** The **roof** of the anatomical snuff box is formed by the **skin, superficial fascia**, and its contents. The most significant structures within this fascia are the **superficial branch of the radial nerve** (providing sensation to the dorsal aspect of the lateral 3.5 fingers) and the **cephalic vein**. Therefore, the superficial branch of the radial nerve is a primary constituent of the roof. **2. Why the Other Options are Incorrect:** * **Option A (Radial Artery):** This is the most important structure in the **floor** of the snuff box, not the roof. It pulses against the scaphoid and trapezium bones. * **Option B (Basilic Artery):** There is no "basilic artery" in standard human anatomy (the basilic vein is on the medial side of the forearm). * **Option D (Superficial branch of the ulnar nerve):** This nerve supplies the medial side of the hand and does not enter the lateral territory of the snuff box. **3. NEET-PG High-Yield Pearls:** * **Boundaries:** * *Anterior/Lateral:* Tendons of Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) [1]. * *Posterior/Medial:* Tendon of Extensor Pollicis Longus (EPL) [1]. * **Floor:** Formed by the **Scaphoid** and **Trapezium** bones. * **Clinical Significance:** Tenderness in the snuff box is a classic sign of a **Scaphoid fracture**, the most commonly fractured carpal bone, which carries a high risk of avascular necrosis.

Q: Rupture of supraspinatus tendon manifests as which of the following?

Difficulty in initiation of abduction. ### Explanation **Correct Answer: C. Difficulty in initiation of abduction** The **Supraspinatus** is one of the four rotator cuff muscles and plays a critical role in the biomechanics of the shoulder joint. Its primary function is to **initiate the first 0° to 15° of abduction** at the glenohumeral joint. It acts by stabilizing the humeral head against the glenoid cavity, providing a fulcrum for the deltoid muscle to take over. When the supraspinatus tendon is ruptured (most commonly at its insertion on the greater tubercle), the patient cannot initiate abduction independently and often has to "shrug" or lean to the side to start the movement. **Analysis of Incorrect Options:** * **A. Painful movements:** While a partial tear or supraspinatus tendinitis causes a "Painful Arc" (pain between 60°–120°), a complete rupture is specifically characterized by the functional loss of movement initiation. * **B. Flat shoulders:** This is a classic sign of **Axillary nerve injury** or shoulder dislocation, resulting from atrophy of the Deltoid muscle, not a supraspinatus tear. * **D. Difficulty in abduction after 90°:** Abduction from 90° to 180° involves the rotation of the scapula by the **Serratus Anterior** and **Trapezius** muscles. Supraspinatus pathology does not primarily affect this range. **Clinical Pearls for NEET-PG:** * **Rotator Cuff (SITS):** Supraspinatus, Infraspinatus, Teres minor, and Subscapularis. * **The

Q: A neurologist notes that a patient has weakness when she attempts internal rotation of her right arm at the shoulder. This could be caused by weakness in which of the following muscles?

Subscapularis. **Explanation:** The movement described is **internal (medial) rotation** of the humerus at the glenohumeral joint. To identify the correct muscle, one must understand the functional anatomy of the rotator cuff and the pectoral girdle. **Why Subscapularis is Correct:** The **Subscapularis** is the only member of the rotator cuff muscles that originates on the anterior surface of the scapula (subscapular fossa) and inserts into the **lesser tubercle** of the humerus. Because of its anterior position relative to the joint axis, its primary action is the **internal rotation** of the arm. It also helps stabilize the humeral head in the glenoid cavity. **Analysis of Incorrect Options:** * **Infraspinatus (A):** This muscle inserts onto the greater tubercle (posterior aspect). Its primary function is **external (lateral) rotation**, making it an antagonist to the subscapularis. * **Pectoralis minor (B):** This muscle inserts into the coracoid process of the scapula. It acts on the scapula (protraction and depression) rather than directly rotating the humerus. * **Supraspinatus (D):** This muscle initiates the first 15 degrees of **abduction**. It does not significantly contribute to rotation. **High-Yield Clinical Pearls for NEET-PG:** * **Rotator Cuff Mnemonic (SITS):** Supraspinatus (Abduction), Infraspinatus (External rotation), Teres minor (External rotation), Subscapularis (Internal rotation). * **Nerve Supply:** Subscapularis is supplied by the **upper and lower subscapular nerves** (C5, C6). * **Clinical Test:** The **Gerber’s Lift-off test** is specifically used to assess subscapularis weakness or tears. * **The "Lady between two majors":** Remember that the Latissimus dorsi (internal rotator) inserts into the bicipital groove between the Pectoralis major and Teres major (both also internal rotators).

Q: Which of the following statements is true regarding the shoulder joint?

Allows flexion, rotation, and abduction. Explanation: The shoulder joint (glenohumeral joint) is a **multiaxial ball-and-socket synovial joint** characterized by a high degree of mobility at the expense of stability. **Why Option D is Correct:** The shoulder joint possesses three degrees of freedom, allowing movement in all planes: * **Transverse axis:** Flexion and Extension. * **Anteroposterior axis:** Abduction and Adduction. * **Vertical axis:** Internal and External Rotation. * **Combination:** Circumduction. **Analysis of Incorrect Options:** * **Option A:** The "shoulder complex" is actually composed of **four joints**: the Glenohumeral, Acromioclavicular, Sternoclavicular, and the Scapulothoracic (a physiological/functional joint). * **Option B:** Scapular gliding is essential for shoulder function. **Protraction and Retraction** are essentially anterior and posterior gliding movements of the scapula along the chest wall, facilitated by the serratus anterior and trapezius/rhomboids. * **Option C:** While the acromioclavicular joint is vital for overhead reach, the **Glenohumeral joint** is the primary functional component of the shoulder, providing the majority of the range of motion. **High-Yield NEET-PG Pearls:** * **Stability:** Provided by the **Rotator Cuff (SITS muscles)** and the **Glenoid Labrum** (fibrocartilaginous rim that deepens the cavity). * **Weakest Point:** The inferior aspect of the capsule is the least supported, making **Anterior-inferior dislocation** the most common type. * **Scapulohumeral Rhythm:** For every 3° of abduction, 2° occurs at the glenohumeral joint and 1° occurs at the scapulothoracic joint (2:1 ratio). * **Nerve Supply:** Suprascapular, Axillary, and Lateral pectoral nerves (Hilton’s Law).

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.

Question 1

What is the arterial supply to the latissimus dorsi muscle?

Accepted Answer

Subscapular artery

Answer

Circumflex humeral artery

Answer

Thoracodorsal artery

Answer

Lateral thoracic artery

Question 2

Which of the following muscles is known as the 'climber's muscle'?

Accepted Answer

Latissimus dorsi

Answer

Serratus anterior

Answer

Rhomboidus major

Answer

Subscapularis

Question 3

What forms the roof of the anatomical snuff box?

Accepted Answer

Superficial branch of the radial nerve

Answer

Radial artery

Answer

Basilic artery

Answer

Superficial branch of the ulnar nerve

Question 4

Rupture of supraspinatus tendon manifests as which of the following?

Accepted Answer

Difficulty in initiation of abduction

Answer

Painful movements

Answer

Flat shoulders

Answer

Difficulty in abduction after 90°

Question 5

A 35-year-old patient has a small but painful tumor under the nail of the little finger. Which of the following nerves would have to be anesthetized for a painless removal of the tumor?

Accepted Answer

Common palmar digital nerve of the ulnar nerve

Answer

Superficial radial nerve

Answer

Common palmar digital nerve of the median nerve

Answer

Deep radial nerve

Question 6

A neurologist notes that a patient has weakness when she attempts internal rotation of her right arm at the shoulder. This could be caused by weakness in which of the following muscles?

Accepted Answer

Subscapularis

Answer

Infraspinatus

Answer

Pectoralis minor

Answer

Supraspinatus

Question 7

Which of the following statements is true regarding the shoulder joint?

Accepted Answer

Allows flexion, rotation, and abduction

Answer

Composed of only 2 joints

Answer

Anterior-posterior gliding of the scapula never occurs

Answer

The acromio-clavicular joint is more important

Question 8

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 9

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 10

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.

Upper Limb — MCQs

Upper Limb — MCQs

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