Nerve Injuries in Hand — MCQs
Which of the following is true about nerve injuries?
Phalen's test is done for which nerve injury?
Which muscle will be paralyzed when the radial nerve is injured just below the spiral groove?
Saturday night palsy is which type of nerve injury?
Ulnar nerve injury results in:
Median nerve injury at the wrist is commonly tested by.
Median nerve injury at the wrist causes -
A 50-year-old female presents with wrist drop. Which nerve is most likely involved?
A 22-year-old male medical student was seen in the emergency department with a complaint of pain in his hand. He confessed that he had hit a vending machine in the hospital when he did not receive his soft drink after inserting money twice. The medial side of the dorsum of the hand was quite swollen, and one of his knuckles could not be seen when he "made a fist." The physician made a diagnosis of a "boxer's fracture." What was the nature of the impatient student's injury?
A 54-year-old female marathon runner presents with pain in her right wrist that resulted from a fall onto her outstretched hand. Radiographic studies indicate an anterior dislocation of a carpal bone. Which of the following bones is most likely dislocated?
Nerve Injuries in Hand Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following is true about nerve injuries?
- A. Froment sign seen in median nerve palsy is due to Flexor pollicis longus action
- B. All lumbricals are supplied by median nerve
- C. Waenburg sign is seen in median nerve palsy
- D. Median nerve is also named as labourer's nerve (Correct Answer)
Explanation: ***Median nerve is also named as labourer's nerve*** - The median nerve is sometimes called the "laborer's nerve" because it innervates many of the muscles essential for **fine motor control** and **dexterous hand movements** predominantly used in manual labor. [1] - It supplies most of the **flexors in the forearm** and several intrinsic hand muscles, making it crucial for a strong grip and coordinated hand actions. [1] *Froment sign seen in median nerve palsy is due to Flexor pollicis longus action* - **Froment's sign** is observed in **ulnar nerve palsy**, not median nerve palsy. - It occurs when the adductor pollicis is weak, and the **flexor pollicis longus** (median nerve-innervated) compensates by hyperflexing the interphalangeal joint of the thumb to grasp an object. *All lumbricals are supplied by median nerve* - The **first two lumbricals** (from the radial side) are typically supplied by the **median nerve**. [1] - The **third and fourth lumbricals** (from the ulnar side) are supplied by the **ulnar nerve**. [1] *Waenburg sign is seen in median nerve palsy* - There is no widely recognized clinical sign called "Waenburg sign" associated with median nerve palsy. - Common signs of **median nerve palsy** include **ape hand deformity**, **hand of benediction**, and sensory loss in the radial three and a half digits. [1]
Question 2: Phalen's test is done for which nerve injury?
- A. Median (Correct Answer)
- B. Radial
- C. Ulnar
- D. Axillary
Explanation: ***Median*** - **Phalen's test** is used to diagnose **carpal tunnel syndrome**, which results from compression of the **median nerve** as it passes through the wrist. - The test involves holding the wrists in maximal flexion for 30-60 seconds, which increases pressure on the median nerve. *Radial* - The **radial nerve** is primarily involved in wrist and finger extension, and its injury typically results in **wrist drop**. - No specific provocative test like Phalen's is associated with radial nerve compression at the wrist. *Ulnar* - The **ulnar nerve** innervates muscles in the hand and forearm, and its injury can present as a "claw hand" deformity. - Tests such as **Tinel's sign at the cubital tunnel** are used for ulnar nerve compression, not Phalen's test. *Axillary* - The **axillary nerve** innervates the deltoid and teres minor muscles and provides sensation over the lateral shoulder. - Injury often occurs with shoulder dislocations and causes **deltoid weakness** and **sensory loss over the lateral arm**, which is completely unrelated to Phalen's test.
Question 3: Which muscle will be paralyzed when the radial nerve is injured just below the spiral groove?
- A. Extensor Digitorum
- B. Extensor Carpi Radialis Brevis (Correct Answer)
- C. Supinator
- D. Abductor Pollicis Longus
Explanation: Extensor Carpi Radialis Brevis - The radial nerve travels in the spiral groove of the humerus and gives off branches in a specific sequence. - Proximal to the spiral groove: Branches to triceps and anconeus - Within/at the spiral groove: Branches to brachioradialis and extensor carpi radialis longus (ECRL) - Just distal to the spiral groove: Branch to extensor carpi radialis brevis (ECRB) [1] - this is the first branch after exiting the spiral groove - More distally: The nerve divides into superficial and deep branches (posterior interosseous nerve) [1] - An injury just below the spiral groove would paralyze ECRB while sparing muscles innervated proximal to or within the groove (triceps, anconeus, brachioradialis, ECRL). Supinator - The supinator is innervated by the deep branch of the radial nerve (posterior interosseous nerve), which branches off more distally in the proximal forearm. - This muscle would only be affected by injuries distal to the bifurcation of the radial nerve into superficial and deep branches, not by an injury just below the spiral groove. Extensor Digitorum - The extensor digitorum is supplied by the posterior interosseous nerve, which is a continuation of the deep branch [1]. - This innervation occurs significantly distal to the spiral groove in the posterior forearm compartment. - It would be affected by posterior interosseous nerve injuries, not by lesions just below the spiral groove. Abductor Pollicis Longus - The abductor pollicis longus is innervated by the posterior interosseous nerve in the distal forearm [1]. - This is the most distal of all the options and would only be affected by posterior interosseous nerve palsy, not by radial nerve injury at the spiral groove level [1].
Question 4: Saturday night palsy is which type of nerve injury?
- A. Neuropraxia (Correct Answer)
- B. Axonotemesis
- C. Complete section
- D. Neurotmesis
Explanation: ***Neuropraxia*** - This is the mildest form of nerve injury, involving a **temporary conduction block** without axonal disruption, often due to **compression** or mild stretching. - **Saturday night palsy**, caused by prolonged compression of the radial nerve, is a classic example, characterized by rapid and complete recovery, typically within days to weeks. *Axonotemesis* - This involves **axon damage** and Wallerian degeneration distal to the injury, but the **endoneurium and connective tissue sheaths remain intact**. - Recovery is slower and often incomplete, as it requires axonal regeneration through the preserved connective tissue tubes, taking months. *Neurotmesis* - This is the most severe type of nerve injury, involving **complete transection of the nerve fiber**, including the axon, myelin, and all connective tissue sheaths. - Recovery is often poor and requires surgical intervention to attempt re-approximation of the nerve ends. *Complete section* - This term is largely synonymous with **neurotmesis**, indicating a full anatomical disruption of the nerve. - It involves the severance of all nerve components, leading to complete loss of function distal to the injury and the poorest prognosis for spontaneous recovery.
Question 5: Ulnar nerve injury results in:
- A. Pointing index
- B. Ape thumb deformity
- C. Clawing of fingers (Correct Answer)
- D. Wrist drop
Explanation: ***Clawing of fingers*** - An ulnar nerve injury, particularly at the elbow, often leads to **paralysis of the interossei muscles** and the **medial two lumbricals**. [1] - This results in **hyperextension at the metacarpophalangeal joints** and **flexion at the interphalangeal joints** of the 4th and 5th fingers (and sometimes 3rd), creating the characteristic claw hand deformity. [1] *Pointing index* - **Pointing index**, also known as the **sign of benediction** or **preacher's hand**, occurs with **high median nerve lesions** affecting the lateral lumbricals and flexor digitorum superficialis. - The patient is unable to flex the index and middle fingers, especially when attempting to make a fist. *Ape thumb deformity* - **Ape thumb deformity** is caused by a **median nerve injury**, specifically affecting the **thenar muscles** (abductor pollicis brevis, opponens pollicis, and superficial head of flexor pollicis brevis). - This paralysis leads to the thumb being pulled laterally and into the same plane as the other fingers, losing its ability to oppose. *Wrist drop* - **Wrist drop** is a classic sign of **radial nerve injury**, which paralyzes the **extensor muscles of the wrist and fingers**. - This prevents the patient from extending their wrist and metacarpophalangeal joints.
Question 6: Median nerve injury at the wrist is commonly tested by.
- A. Contraction of abductor pollicis brevis (Correct Answer)
- B. Loss of sensation on palm
- C. Loss of sensation on ring finger
- D. Contraction of flexor pollicis brevis
Explanation: ***Contraction of abductor pollicis brevis*** - The **abductor pollicis brevis (APB)** is primarily innervated by the **median nerve**, and its motor function is often the **first to be affected** and is a reliable test for median nerve integrity at the wrist. - Testing the **abduction of the thumb** against resistance (often called the "OK" sign or simply checking for strength) directly assesses the function of the APB and therefore the median nerve. *Contraction of flexor pollicis brevis* - The **flexor pollicis brevis (FPB)** has a **dual innervation**; its superficial head is supplied by the median nerve, but its deep head is often supplied by the ulnar nerve. - This dual innervation makes its contraction an unreliable isolated test for median nerve injury, as ulnar nerve compensation might mask a median nerve deficit. *Loss of sensation on palm* - While the median nerve supplies sensation to the radial side of the palm, an injury at the wrist, specifically within the **carpal tunnel**, typically spares the palmar cutaneous branch. - The **palmar cutaneous branch** of the median nerve arises proximal to the carpal tunnel and provides sensation to the thenar eminence and central palm, so its sensation is often preserved even with significant carpal tunnel syndrome. *Loss of sensation on ring finger* - The **ring finger** receives sensory innervation from both the **median nerve** (radial half) and the **ulnar nerve** (ulnar half). - Therefore, isolated loss of sensation on the ring finger would not be a definitive test for median nerve injury alone, as it requires assessment of both nerve distributions.
Question 7: Median nerve injury at the wrist causes -
- A. Policeman's tip deformity
- B. Saturday night palsy
- C. Loss of apposition of thumb (Correct Answer)
- D. Claw hand
Explanation: ***Loss of apposition of thumb*** - A **median nerve injury at the wrist** specifically affects the **motor branches to the thenar muscles**, including the **opponens pollicis, abductor pollicis brevis, and the superficial head of flexor pollicis brevis**. - This leads to an inability to **oppose the thumb** to the other fingers, significantly impairing fine motor skills and grasping. - Also causes sensory loss over the **lateral 3½ digits** (thumb, index, middle, and lateral half of ring finger). *Policeman's tip deformity* - This term is **not a standard clinical description** and may be confused with **waiter's tip hand** (Erb's palsy). - **Waiter's tip hand** results from injury to the **upper trunk of the brachial plexus (C5-C6)**, causing adduction and internal rotation of the shoulder with extension and pronation of the elbow. - This is a **completely different clinical picture** from median nerve injury at the wrist and involves proximal nerve injury, not peripheral nerve injury. *Saturday night palsy* - This condition is caused by **compression of the radial nerve** in the spiral groove of the humerus, often from prolonged pressure (e.g., falling asleep with an arm over a chair). - It results in **wrist drop** and impaired extension of the fingers and thumb, not specific thumb apposition issues. *Claw hand* - A claw hand deformity is typically caused by an injury to the **ulnar nerve** (affecting the medial two fingers more prominently) or a combined **median and ulnar nerve injury** (affecting all fingers). - It involves **hyperextension of the MCP joints** and **flexion of the IP joints** of the fingers, which is distinct from isolated thumb apposition loss seen in median nerve injury.
Question 8: A 50-year-old female presents with wrist drop. Which nerve is most likely involved?
- A. Ulnar Nerve
- B. Radial Nerve (Correct Answer)
- C. Median Nerve
- D. Musculocutaneous Nerve
Explanation: ***Radial Nerve*** - **Wrist drop** is a classic symptom of **radial nerve** injury, which compromises the innervation of the **extensor muscles** of the wrist and fingers. - The radial nerve supplies motor function to the **triceps brahii**, brachioradialis, supinator, and the wrist and finger extensors. *Ulnar Nerve* - Injury to the ulnar nerve typically causes a **claw hand deformity** due to paralysis of the **interossei** and **lumbricals 3 and 4**, with sparing of the finger extensors. - Patients experience weakness in **finger adduction and abduction**, as well as sensory loss over the medial 1.5 digits and hypothenar eminence. *Median Nerve* - Median nerve injury often results in an **ape hand deformity** or **hand of benediction** (when attempting to make a fist), affecting muscles responsible for **thumb opposition** and **flexion of digits 2 and 3**. - It would not cause wrist drop, as the wrist extensors are innervated by the radial nerve. *Musculocutaneous Nerve* - Injury to the musculocutaneous nerve primarily affects the **biceps brachii** and **brachialis muscles**, leading to weakness in **elbow flexion** and **supination of the forearm**. - It does not innervate any muscles responsible for wrist extension or flexion, therefore it would not cause wrist drop.
Question 9: A 22-year-old male medical student was seen in the emergency department with a complaint of pain in his hand. He confessed that he had hit a vending machine in the hospital when he did not receive his soft drink after inserting money twice. The medial side of the dorsum of the hand was quite swollen, and one of his knuckles could not be seen when he "made a fist." The physician made a diagnosis of a "boxer's fracture." What was the nature of the impatient student's injury?
- A. Colles' fracture of the radius
- B. Fracture of the styloid process of the ulna
- C. Smith's fracture of the radius
- D. Fracture of the neck of the fifth metacarpal (Correct Answer)
Explanation: ***Fracture of the neck of the fifth metacarpal*** - A **boxer's fracture** specifically refers to a fracture of the neck of the fifth metacarpal bone. - This injury commonly occurs when punching a hard object, leading to swelling and loss of the knuckle prominence. *Colles' fracture of the radius* - A **Colles' fracture** involves the distal radius, typically caused by a fall on an outstretched hand, resulting in a "dinner fork" deformity. - It does not involve the metacarpals or knuckles. *Fracture of the styloid process of the ulna* - This fracture often accompanies a **Colles' fracture** of the radius but can also occur in isolation. - It's a fracture of the distal end of the ulna and does not cause the loss of a knuckle. *Smith's fracture of the radius* - A **Smith's fracture** is a fracture of the distal radius with volar displacement, often called a "reverse Colles' fracture." - It is caused by a fall on the back of the hand or a direct blow to the forearm and does not affect the metacarpals or knuckles.
Question 10: A 54-year-old female marathon runner presents with pain in her right wrist that resulted from a fall onto her outstretched hand. Radiographic studies indicate an anterior dislocation of a carpal bone. Which of the following bones is most likely dislocated?
- A. Capitate
- B. Lunate (Correct Answer)
- C. Trapezoid
- D. Triquetrum
Explanation: ***Lunate*** - The **lunate bone** is the most commonly dislocated carpal bone, especially with a fall onto an **outstretched hand**. - Its central position in the proximal carpal row and its articulation with the radius make it vulnerable to **anterior dislocation** with forced dorsiflexion. *Capitate* - The **capitate** is the largest carpal bone but is more stable due to its central position and strong ligamentous attachments. - Isolated dislocation of the capitate is **rare** and usually accompanies other carpal injuries. *Trapezoid* - The **trapezoid** is a small, irregularly shaped carpal bone in the distal row, which is very stable. - Its strong articulations with the trapezium, capitate, and second metacarpal make its dislocation **extremely uncommon**. *Triquetrum* - The **triquetrum** is the second most commonly fractured carpal bone but is less prone to dislocation than the lunate. - While it can dislocate, it typically occurs with **ulnar impaction** or other complex carpal instabilities rather than an isolated anterior dislocation from a fall onto an outstretched hand.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free