Upper Limb Practice Questions

Q: A 61-year-old man sustained an injury to his left mid-humeral region from a cricket bat. Physical examination shows normal elbow motion, but he is unable to extend his wrist or metacarpophalangeal joints. He also reports a loss of sensation on a small area of skin on the dorsum of the hand, proximal to the first two digits. Radiographic examination reveals a hairline fracture of the humeral shaft just distal to its midpoint. Which of the following nerves is most likely injured?

Radial. **Explanation:** The clinical presentation points to an injury of the **Radial Nerve** within the **spiral groove** of the humerus. **1. Why Radial Nerve is Correct:** The radial nerve travels in the spiral groove along the posterior aspect of the **mid-shaft of the humerus**. A fracture in this region commonly compresses or lacerates the nerve. * **Motor Loss:** The nerve supplies the extensors of the wrist and fingers. Injury leads to **Wrist Drop** (inability to extend the wrist) and inability to extend the metacarpophalangeal (MCP) joints. * **Sensory Loss:** It provides sensation to the **dorsum of the hand** (lateral 3.5 digits and associated thumb web space). * **Note on Elbow:** Elbow extension (Triceps) is usually **preserved** because the branches to the long and medial heads of the triceps arise proximal to the spiral groove. **2. Why Other Options are Incorrect:** * **Median Nerve:** Typically injured at the elbow (supracondylar fracture) or wrist (carpal tunnel). Injury would cause "Ape Hand" deformity and loss of thumb opposition, not wrist drop. * **Ulnar Nerve:** Usually injured at the medial epicondyle or Guyon’s canal. It results in "Claw Hand" and sensory loss over the medial 1.5 fingers. * **Musculocutaneous Nerve:** Supplies the coracobrachialis, biceps brachii, and brachialis. Injury would result in weak elbow flexion and loss of sensation on the lateral forearm, not wrist drop. **Clinical Pearls for NEET-PG:** * **Holstein-Lewis Fracture:** A spiral fracture of the distal one-third of the humerus specifically associated with radial nerve palsy. * **Saturday Night Palsy:** Compression of the radial nerve in the axilla (presents with wrist drop **plus** loss of triceps reflex). * **PIN (Posterior Interosseous Nerve) Palsy:** Occurs at the Arcade of Frohse; presents with finger drop but **no sensory loss** and **no wrist drop** (ECRL is spared).

Q: Which nerve is related to the anatomical snuff box?

Superficial branch of radial nerve. ### Explanation The **anatomical snuff box** is a triangular depression on the lateral aspect of the wrist. The correct answer is the **superficial branch of the radial nerve** because it crosses the roof of this space. **1. Why the Correct Answer is Right:** The anatomical snuff box is bounded medially by the tendon of the Extensor Pollicis Longus (EPL) and laterally by the tendons of the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) [1]. The **superficial branch of the radial nerve** (a purely sensory nerve) passes over these lateral tendons to lie in the roof (skin and fascia) of the snuff box. It provides sensory innervation to the skin of the dorsal surface of the lateral three and a half fingers. **2. Why the Other Options are Wrong:** * **Ulnar Nerve:** This nerve enters the hand through Guyon’s canal, located on the medial (ulnar) side of the wrist, far from the lateral snuff box [1]. * **Median Nerve:** This nerve passes through the carpal tunnel deep to the flexor retinaculum on the volar (palmar) aspect of the wrist [1]. * **Axillary Nerve:** This nerve is located in the shoulder region (axilla), winding around the surgical neck of the humerus; it does not extend to the forearm or wrist. **3. High-Yield Clinical Pearls for NEET-PG:** * **Contents:** The **Radial Artery** lies in the floor of the snuff box (where the radial pulse can be felt). * **Bony Floor:** The **Scaphoid** and **Trapezium** bones form the floor [1]. Tenderness in the snuff box after a fall on an outstretched hand (FOOSH) is pathognomonic for a **Scaphoid fracture**. * **Cephalic Vein:** This vein begins in the anatomical snuff box from the dorsal venous network.

Q: The deep branch of the ulnar nerve innervates which of the following?

Dorsal interossei. The ulnar nerve is the "musician's nerve," responsible for the fine motor movements of the hand. After passing through Guyon’s canal, it divides into superficial and deep branches. **Why the Correct Answer is Right:** The **deep branch of the ulnar nerve** is primarily motor. It supplies most of the intrinsic muscles of the hand, including: * All **Interossei** (4 Dorsal and 3 Palmar). * The **III and IV Lumbricals** [2]. * All **Hypothenar muscles** (except Palmaris brevis) [2]. * The **Adductor pollicis** (the only thenar muscle supplied by the ulnar nerve). **Explanation of Incorrect Options:** * **A. I and II lumbricals:** These are supplied by the **Median nerve** [1]. (Mnemonic: 1st and 2nd Lumbricals = 1st and 2nd digits = Median nerve). * **B. Palmaris brevis:** This is the only muscle supplied by the **superficial branch** of the ulnar nerve [2]. * **D. Opponens pollicis:** This is part of the thenar eminence, supplied by the **recurrent branch of the Median nerve**. **High-Yield Clinical Pearls for NEET-PG:** * **Ulnar Claw Hand:** Results from a lesion at the wrist; characterized by hyperextension at MCP joints and flexion at IP joints of the 4th and 5th digits. * **Froment’s Sign:** Tests for Adductor pollicis palsy (Deep branch of ulnar nerve). The patient compensates by flexing the FPL (Median nerve), causing the thumb joint to bend when gripping paper. * **Dorsal Interossei (DAB):** **D**orsal **Ab**duct the fingers. * **Palmar Interossei (PAD):** **P**almar **Ad**duct the fingers.

Q: Regimental band anesthesia is due to a lesion of which nerve?

Axillary nerve. **Regimental badge anesthesia** (also known as regimental band anesthesia) refers to a loss of sensation over the lower half of the deltoid muscle. This specific area of skin is supplied by the **Superior Lateral Cutaneous Nerve of the Arm**, which is a direct branch of the **Axillary Nerve (C5, C6)**. 1. **Why Axillary Nerve is Correct:** The axillary nerve passes through the quadrangular space and winds around the surgical neck of the humerus. It provides motor supply to the deltoid and teres minor muscles and sensory supply to the skin over the deltoid. A lesion (commonly due to shoulder dislocation or fracture of the surgical neck of the humerus) results in sensory loss in this "badge-like" distribution. 2. **Why Other Options are Incorrect:** * **Musculocutaneous Nerve:** Supplies the coracobrachialis, biceps brachii, and brachialis. Its sensory continuation is the *Lateral Cutaneous Nerve of the Forearm*, supplying the lateral aspect of the forearm, not the shoulder. * **Long Thoracic Nerve:** Supplies the Serratus Anterior muscle. Injury leads to "winging of scapula" but causes no sensory loss. * **Spinal Accessory Nerve:** A cranial nerve (CN XI) that supplies the Trapezius and Sternocleidomastoid muscles. Injury causes drooping of the shoulder but no localized sensory loss over the deltoid. **Clinical Pearls for NEET-PG:** * **Site of Injury:** Most common sites for axillary nerve damage are **dislocation of the shoulder joint** and **fracture of the surgical neck of the humerus**. * **Motor Deficit:** Paralysis of the deltoid leads to loss of abduction of the arm from 15° to 90°. * **Deformity:** Chronic axillary nerve palsy leads to atrophy of the deltoid, resulting in the **"Flat Shoulder"** appearance.

Q: Which of the following muscles is a prototype example of a multipennate muscle?

Deltoid. The classification of muscles based on fascicular architecture is a high-yield topic in Anatomy. Muscle fibers can be arranged parallel to the line of pull or obliquely (pennate). **1. Why Deltoid is Correct:** The **Deltoid** (specifically its middle/acromial fibers) is the classic example of a **multipennate muscle**. In this arrangement, several septa of connective tissue extend into the muscle from the origin, and several septa extend upward from the insertion. The muscle fibers run obliquely between these septa. This design allows for a large number of muscle fibers to be packed into a small area, prioritizing **power/force** over the range of motion. **2. Analysis of Incorrect Options:** * **Biceps Brachii:** This is a **parallel/fusiform muscle**. The fibers run parallel to the long axis, allowing for a greater range of movement and speed of contraction but less power compared to pennate muscles. * **Brachioradialis:** This is a **parallel/strap-like muscle**. It is designed for speed and acts as a "shunt muscle" to stabilize the elbow joint during rapid movements. * **Palmaris Brevis:** This is a **corrugated/flat muscle** located in the subcutaneous tissue of the hypothenar eminence. It is not a pennate muscle. **3. NEET-PG High-Yield Pearls:** * **Unipennate:** Fibers on one side of the tendon (e.g., Flexor Pollicis Longus, Extensor Digitorum Longus). * **Bipennate:** Fibers on both sides of a central tendon (e.g., Rectus Femoris, Dorsal Interossei). * **Circumpennate:** Fibers converge to a central tendon from all sides (e.g., Tibialis Anterior). * **Clinical Note:** The multipennate nature of the middle deltoid makes it the strongest abductor of the shoulder, but it only becomes effective after the first 15° of abduction (initiated by the Supraspinatus).

Q: Which anatomical location describes the Level I axillary lymph nodes?

Lateral to pectoralis minor. The classification of axillary lymph nodes is a high-yield topic for NEET-PG, based on their anatomical relationship to the **pectoralis minor muscle**. This muscle serves as the key landmark for surgical levels (Berg’s levels) [1]. ### **1. Why Option A is Correct** The axillary lymph nodes are divided into three levels: * **Level I (Low Axilla):** These nodes are located **lateral and inferior** to the lateral border of the pectoralis minor [1]. This group includes the anterior (pectoral), posterior (subscapular), and lateral (humeral) node groups. * **Level II (Mid Axilla):** These nodes lie **deep/posterior** to the pectoralis minor [1]. This level also includes the Rotter’s (interpectoral) nodes. * **Level III (High Axilla):** These nodes are located **medial and superior** to the medial border of the pectoralis minor, extending up to the lower border of the clavicle (apical nodes). ### **2. Why Other Options are Incorrect** * **Option B:** Medial to the pectoralis minor describes **Level III** nodes. * **Options C & D:** The **pectoralis major** is not the anatomical landmark used for surgical staging of axillary nodes. While it forms the anterior wall of the axilla, the levels are strictly defined by the pectoralis minor [1]. ### **3. Clinical Pearls for NEET-PG** * **Sentinel Lymph Node (SLN):** The first node to receive drainage from a primary tumor (usually in Level I). * **Surgical Significance:** In Axillary Lymph Node Dissection (ALND) for breast cancer, Level I and II nodes are typically removed [1]. Level III is only cleared if gross disease is present. * **Nerve at Risk:** During dissection of Level I and II, the **Long Thoracic Nerve** (supplying Serratus Anterior) and the **Thoracodorsal Nerve** (supplying Latissimus Dorsi) must be preserved to avoid "winged scapula" and loss of adduction/internal rotation, respectively [2].

Question 1

A 61-year-old man sustained an injury to his left mid-humeral region from a cricket bat. Physical examination shows normal elbow motion, but he is unable to extend his wrist or metacarpophalangeal joints. He also reports a loss of sensation on a small area of skin on the dorsum of the hand, proximal to the first two digits. Radiographic examination reveals a hairline fracture of the humeral shaft just distal to its midpoint. Which of the following nerves is most likely injured?

Accepted Answer

Radial

Answer

Median

Answer

Ulnar

Answer

Musculocutaneous

Question 2

A 47-year-old female tennis player presents with a rotator cuff injury requiring surgery. Her physician explains that repetitive stress from playing has caused gradual damage to an underlying muscle by a shoulder ligament. Which of the following ligaments is most likely implicated?

Accepted Answer

Coracoacromial ligament

Answer

Acromioclavicular ligament

Answer

Coracohumeral ligament

Answer

Glenohumeral ligament

Question 3

A 69-year-old woman visits the outpatient clinic with a complaint of numbness and tingling of her hand for the past 3 months. Physical examination reveals she has numbness and pain in the lateral three digits of her right hand that are relieved by vigorous shaking of the wrist. In addition, the abductor pollicis brevis, opponens pollicis, and the first two lumbrical muscles are weakened. Sensation was decreased over the lateral palm and the volar aspect of the first three digits. Which of the following nerves is most likely compressed?

Accepted Answer

Median

Answer

Ulnar

Answer

Radial

Answer

Recurrent median

Question 4

What is the ulnar collateral nerve?

Accepted Answer

A branch of the radial nerve supplying the medial head of the biceps.

Answer

A branch of the ulnar nerve.

Answer

A branch of the radial nerve supplying the long head of the biceps.

Answer

A branch of the radial nerve supplying the lateral head of the triceps.

Question 5

Which nerve is related to the anatomical snuff box?

Accepted Answer

Superficial branch of radial nerve

Answer

Ulnar nerve

Answer

Median nerve

Answer

Axillary nerve

Question 6

The deep branch of the ulnar nerve innervates which of the following?

Accepted Answer

Dorsal interossei

Answer

I and II lumbricals

Answer

Palmaris brevis

Answer

Opponens pollicis

Question 7

Regimental band anesthesia is due to a lesion of which nerve?

Accepted Answer

Axillary nerve

Answer

Musculocutaneous nerve

Answer

Long thoracic nerve

Answer

Spinal accessory nerve

Question 8

Which of the following muscles is a prototype example of a multipennate muscle?

Accepted Answer

Deltoid

Answer

Biceps

Answer

Brachioradialis

Answer

Palmaris brevis

Question 9

Which anatomical location describes the Level I axillary lymph nodes?

Accepted Answer

Lateral to pectoralis minor

Answer

Medial to pectoralis minor

Answer

Lateral to pectoralis major

Answer

Medial to pectoralis major

Question 10

Which nerve supplies the abductor pollicis brevis muscle?

Accepted Answer

Median nerve

Answer

Ulnar nerve

Answer

Ulnar and Median nerve

Answer

Radial nerve

Upper Limb — MCQs

Upper Limb — MCQs

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