Upper Limb Practice Questions

Q: A 45-year-old male presents with injuries to his left elbow after a fall. Radiographic and MRI examinations reveal a fracture of the medial epicondyle and a torn ulnar nerve. Which of the following muscles would be most likely to be paralyzed?

Flexor carpi ulnaris. **Explanation:** The **ulnar nerve** (C8–T1) passes posteriorly to the **medial epicondyle** of the humerus in the cubital tunnel. A fracture in this region is a classic site for ulnar nerve injury. **Why Option D is correct:** In the forearm, the ulnar nerve supplies only **one and a half muscles**: the **Flexor Carpi Ulnaris (FCU)** and the medial half (ulnar part) of the Flexor Digitorum Profundus (FDP). Therefore, a lesion at the medial epicondyle will lead to paralysis of the FCU, resulting in weakened wrist flexion and loss of ulnar deviation. **Why the other options are incorrect:** * **A. Flexor digitorum superficialis:** This muscle is supplied by the **median nerve**. The median nerve passes anterior to the elbow joint and is typically spared in medial epicondyle fractures unless there is significant displacement or associated supracondylar injury. * **B. Biceps brachii:** This is a muscle of the anterior compartment of the arm, supplied by the **musculocutaneous nerve** (C5–C7). * **C. Brachioradialis:** Although it acts as a flexor of the elbow, it is located in the mobile wad of the forearm and is supplied by the **radial nerve** (C5–C7). **Clinical Pearls for NEET-PG:** * **Ulnar Claw Hand:** High ulnar nerve lesions (at the elbow) result in a *less* prominent clawing than low lesions (at the wrist) because the medial half of the FDP is also paralyzed (the "Ulnar Paradox"). * **Froment’s Sign:** Positive due to paralysis of the Adductor Pollicis (supplied by the deep branch of the ulnar nerve). * **Sensory Loss:** Occurs over the medial 1.5 fingers and the hypothenar eminence.

Q: Which tendon is present in the third extensor compartment of the wrist?

Extensor Pollicis Longus (EPL). The extensor retinaculum at the wrist is divided into **six fibro-osseous compartments** by septa attached to the radius and ulna [1]. These compartments house specific tendons and are a high-yield topic for NEET-PG. ### **Why Option C is Correct** The **third compartment** contains only one tendon: the **Extensor Pollicis Longus (EPL)** [1]. * **Anatomical Landmark:** The EPL tendon uses the **Dorsal Tubercle of Lister** (on the radius) as a pulley to change its direction before inserting into the distal phalanx of the thumb. This makes the third compartment unique and clinically significant. ### **Why Other Options are Incorrect** * **Options A & B (ECRL and ECRB):** These are located in the **second compartment** [1]. They insert into the bases of the 2nd and 3rd metacarpals, respectively. * **Option D (EPB):** This is located in the **first compartment** along with the Abductor Pollicis Longus (APL) [1]. Inflammation of this compartment leads to *De Quervain’s Tenosynovitis*. ### **High-Yield Summary of Compartments** | Compartment | Contents | | :--- | :--- | | **1st** | APL, EPB (Lateral boundary of Anatomical Snuffbox) [1] | | **2nd** | ECRL, ECRB [1] | | **3rd** | **EPL** (Medial boundary of Anatomical Snuffbox) [1] | | **4th** | Extensor Digitorum (ED), Extensor Indicis (EI) [1] | | **5th** | Extensor Digiti Minimi (EDM) [1] | | **6th** | Extensor Carpi Ulnaris (ECU) [1] | ### **Clinical Pearl** **Drummer’s Palsy:** Chronic friction or distal radius fractures can lead to the rupture of the EPL tendon within the third compartment due to its sharp turn around Lister’s tubercle.

Q: What is the nerve supply of the pronator teres muscle?

Median nerve. The **Median nerve** is the correct answer. The pronator teres is the most lateral of the superficial flexor muscles of the forearm. It originates from two heads: the humeral head (medial epicondyle) and the ulnar head (coronoid process). The median nerve enters the forearm by passing directly **between these two heads** of the pronator teres, supplying it before continuing down the midline of the forearm. **Analysis of Incorrect Options:** * **Ulnar nerve:** Supplies the flexor carpi ulnaris and the medial half of the flexor digitorum profundus in the forearm. It does not contribute to the superficial lateral flexors. * **Posterior interosseous nerve (PIN):** This is a branch of the radial nerve that supplies the **extensor** compartment of the forearm. * **Radial nerve:** Primarily supplies the extensors of the arm and forearm (e.g., brachioradialis, ECRL). While it is close to the pronator teres at the cubital fossa, it does not provide its motor supply. **Clinical Pearls for NEET-PG:** 1. **Pronator Syndrome:** This occurs when the median nerve is compressed between the two heads of the pronator teres. It presents with pain in the proximal forearm and sensory loss over the thenar eminence (unlike Carpal Tunnel Syndrome, where the palmar cutaneous branch is spared). 2. **Nerve Course:** The median nerve is the "nerve of the front of the forearm," supplying all superficial and intermediate flexors except the flexor carpi ulnaris. 3. **Median Nerve Relation:** In the cubital fossa, the median nerve lies **medial** to the brachial artery (Mnemonic: **MBBR** - Medial to Lateral: Median nerve, Brachial artery, Biceps tendon, Radial nerve).

Q: What is the total number of dorsal interossei muscles in the hand?

4. The **Dorsal Interossei (DI)** are a group of four bipennate muscles located in the metacarpal spaces of the hand [1]. They are essential for the fine motor control of the fingers. **Why Option C is Correct:** There are exactly **four** dorsal interossei muscles. They originate from the adjacent sides of the metacarpal bones (bipennate) and insert into the proximal phalanges and the extensor expansions [1]. Their primary action is **abduction** of the fingers (index, middle, and ring) away from the midline of the hand (the long axis of the middle finger). * **1st DI:** Abducts the index finger. * **2nd & 3rd DI:** Insert on either side of the middle finger (allowing it to move medially and laterally). * **4th DI:** Abducts the ring finger. **Why Other Options are Incorrect:** * **Option A (2) & B (3):** These numbers are incorrect for dorsal interossei. However, note that there are typically **3 Palmar Interossei** (though some texts describe a small 4th at the base of the thumb). * **Option D (5):** There are five metacarpals, but only four intervening spaces to house these muscles. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mnemonic:** **DAB** (Dorsal Abduct) and **PAD** (Palmar Adduct). 2. **Nerve Supply:** All interossei (both palmar and dorsal) are supplied by the **Deep branch of the Ulnar Nerve (C8, T1).** 3. **Clinical Test:** To test the dorsal interossei, ask the patient to spread their fingers against resistance. 4. **Wartenberg’s Sign:** Weakness of the 4th dorsal interosseous leads to an inability to adduct the little finger, often seen in ulnar nerve palsy.

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: A secretary presents with wrist pain from prolonged typing, suggestive of carpal tunnel syndrome. Which of the following findings would support this diagnosis?

Loss of thumb opposition. ### **Explanation** **1. Why the Correct Answer is Right:** Carpal Tunnel Syndrome (CTS) results from the compression of the **Median Nerve** as it passes deep to the flexor retinaculum [1]. The median nerve gives off a **recurrent branch** in the hand, which supplies the **Thenar muscles** (Opponens pollicis, Abductor pollicis brevis, and Flexor pollicis brevis). The **Opponens pollicis** is responsible for thumb opposition. Therefore, chronic compression leads to weakness or loss of this movement and subsequent thenar atrophy. **2. Why the Incorrect Options are Wrong:** * **Option A (Inability to adduct the little finger):** This action is performed by the **Palmar Interossei**, which are supplied by the **Deep branch of the Ulnar Nerve**. * **Option B (Inability to flex the DIP joint of the ring finger):** Flexion of the Distal Interphalangeal (DIP) joints of the ring and little fingers is performed by the medial half of the **Flexor Digitorum Profundus (FDP)**, supplied by the **Ulnar Nerve**. * **Option D (Loss of sensation of the medial 1.5 fingers):** This is the classic sensory distribution of the **Ulnar Nerve**. In CTS, sensory loss occurs in the **lateral 3.5 fingers** [1]. **3. NEET-PG High-Yield Clinical Pearls:** * **Sensory Sparing:** In CTS, sensation over the **thenar eminence** is usually **preserved** because the palmar cutaneous branch of the median nerve arises proximal to the carpal tunnel and passes superficial to the flexor retinaculum [2]. * **Tests for CTS:** * **Phalen’s Test:** Forced wrist flexion for 60 seconds reproduces symptoms. * **Tinel’s Sign:** Percussion over the flexor retinaculum causes tingling in the median nerve distribution. * **Most Common Nerve Involved:** The Median nerve is the most common nerve involved in entrapment neuropathies of the upper limb.

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.

Question 1

A 45-year-old male presents with injuries to his left elbow after a fall. Radiographic and MRI examinations reveal a fracture of the medial epicondyle and a torn ulnar nerve. Which of the following muscles would be most likely to be paralyzed?

Accepted Answer

Flexor carpi ulnaris

Answer

Flexor digitorum superficialis

Answer

Biceps brachii

Answer

Brachioradialis

Question 2

Which tendon is present in the third extensor compartment of the wrist?

Accepted Answer

Extensor Pollicis Longus (EPL)

Answer

Extensor Carpi Radialis Longus (ECRL)

Answer

Extensor Carpi Radialis Brevis (ECRB)

Answer

Extensor Pollicis Brevis (EPB)

Question 3

What is the nerve supply of the pronator teres muscle?

Accepted Answer

Median nerve

Answer

Ulnar nerve

Answer

Posterior interosseous nerve

Answer

Radial nerve

Question 4

What is the total number of dorsal interossei muscles in the hand?

Accepted Answer

4

Answer

2

Answer

3

Answer

5

Question 5

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 6

A secretary presents with wrist pain from prolonged typing, suggestive of carpal tunnel syndrome. Which of the following findings would support this diagnosis?

Accepted Answer

Loss of thumb opposition

Answer

Inability to adduct the little finger

Answer

Inability to flex the DIP joint of the ring finger

Answer

Loss of skin sensation of the medial one and one-half fingers

Question 7

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 8

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 9

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 10

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

Upper Limb — MCQs

Upper Limb — MCQs

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