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7. Hand and Wrist MCQs

Practice Set 78 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1541

Topic: 7. Hand and Wrist

A 40-year-old aquarium enthusiast presents with a chronic, nodular, non-healing ulcer on the dorsum of his hand.

He recalls a minor scrape on coral while cleaning his fish tank several weeks prior. If cultures are to be sent for the suspected organism, what special instruction must be given to the microbiology lab?

. Incubate the culture on Sabouraud dextrose agar at 25°C
. Incubate the culture at 30°C to 32°C
. Incubate the culture in an anaerobic chamber at 37°C
. Perform dark-field microscopy on the fresh sample
. Use polymerase chain reaction for rapid detection of fungal elements

Correct Answer & Explanation

. Incubate the culture on Sabouraud dextrose agar at 25°C

Explanation

The patient's history is classic for 'fish tank granuloma' caused by Mycobacterium marinum, an atypical mycobacterium. M. marinum grows optimally at lower temperatures (30°C to 32°C). Standard bacterial or mycobacterial cultures incubated at normal body temperature (37°C) often yield false-negative results.

Question 1542

Topic: Hand Trauma & Infection

A 35-year-old mechanic presents with an acutely swollen, painful ring finger 2 days after a puncture wound.

You suspect pyogenic flexor tenosynovitis. Which of the following physical examination findings is NOT one of Kanavel's four cardinal signs?

. The affected digit is held in a resting posture of slight flexion
. Uniform, fusiform swelling over the entire length of the digit
. Exquisite tenderness along the anatomical course of the flexor tendon sheath
. Severe pain elicited by active flexion of the digit against resistance
. Severe pain elicited by passive extension of the digit

Correct Answer & Explanation

. The affected digit is held in a resting posture of slight flexion

Explanation

Kanavel's four cardinal signs of flexor tenosynovitis are: 1) fusiform swelling of the digit, 2) finger held in resting slight flexion, 3) tenderness along the flexor tendon sheath, and 4) pain on passive extension. Pain with active flexion is not a Kanavel sign; patients generally refuse to actively move the digit.

Question 1543

Topic: Hand Trauma & Infection
A 22-year-old male presents 3 days after striking an opponent in the mouth during a fistfight. He has a 1 cm laceration over the 3rd metacarpophalangeal joint with surrounding erythema and purulence. During formal surgical I&D, which of the following systemic antibiotic regimens is most appropriate to empirically cover the classic pathogen associated with this specific mechanism?
. Oral cephalexin
. Intravenous vancomycin
. Intravenous ampicillin-sulbactam
. Oral clindamycin
. Oral trimethoprim-sulfamethoxazole

Correct Answer & Explanation

. Intravenous ampicillin-sulbactam

Explanation

This is a 'fight bite' (clenched fist injury against human teeth). The classic associated pathogen is Eikenella corrodens, alongside other mixed flora. Ampicillin-sulbactam (IV) or amoxicillin-clavulanate (PO) are the empiric treatments of choice.

Question 1544

Topic: 7. Hand and Wrist

A 35-year-old aquarium worker sustains a puncture wound to the hand. Six weeks later, he presents with a chronic, granulomatous nodule and flexor tenosynovitis. Cultures are sent. What is the most likely causative organism and its optimal laboratory growth temperature?

. Mycobacterium marinum; grows optimally at 30°C
. Mycobacterium tuberculosis; grows optimally at 37°C
. Sporothrix schenckii; grows optimally at 37°C
. Erysipelothrix rhusiopathiae; grows optimally at 42°C
. Vibrio vulnificus; grows optimally at 25°C

Correct Answer & Explanation

. Mycobacterium marinum; grows optimally at 30°C

Explanation

Mycobacterium marinum is an atypical mycobacterium associated with aquatic environments (fish tanks, non-chlorinated pools). It requires a cooler incubation temperature of roughly 28-32°C (optimally 30°C) for successful culture growth.

Question 1545

Topic: 7. Hand and Wrist
What is the most common complication requiring reoperation after dorsal plating for a distal radius fracture?
. Extensor tenosynovitis
. Extensor tendon rupture
. Flexor pollicus longus tendon rupture
. Loss of reduction
. Dorsal impingement

Correct Answer & Explanation

. Extensor tenosynovitis

Explanation

The most common complication of dorsal plating is extensor tenosynovitis, which often causes pain and is a frequent reason for hardware removal. Other less frequent complications include loss of reduction and extensor tendon ruptures, with flexor tendon ruptures occurring to an even lesser degree.

Question 1546

Topic: 7. Hand and Wrist
What sign or symptom may occur with cubital tunnel syndrome that does not occur with Guyon neuropathy?
. Abnormal sensation of the dorsal ulnar hand
. A positive Froment sign
. Abnormal sensation in the volar ring and small fingers
. Weakness of the interosseous muscles

Correct Answer & Explanation

. Abnormal sensation of the dorsal ulnar hand

Explanation

Ulnar neuropathy at the elbow is termed cubital tunnel syndrome, whereas ulnar nerve compression at the wrist is considered Guyon neuropathy. Patients with cubital tunnel syndrome have numbness on the dorsal ulnar aspect of the hand due to involvement of the dorsal ulnar sensory nerve branch (DUSN). Ulnar neuropathy at both the elbow and the wrist may manifest with abnormal sensation about the volar ring and small fingers and with weakness of the interosseous muscles, which can lead to a positive Froment sign. The Froment sign is considered positive when flexion of the thumb interphalangeal joint occurs to compensate for a lack of adductor function. Patients with a Guyon neuropathy do not have symptoms of numbness in the dorsal ulnar distribution, because the DUSN branch arises more proximally in the forearm and is not compressed in the ulnar tunnel at the wrist.

Question 1547

Topic: 7. Hand and Wrist
A 72-year-old male with pre-existing cervical spondylosis presents after a hyperextension injury sustained in a rear-end motor vehicle collision. He exhibits severe bilateral upper extremity weakness, profound loss of hand dexterity, and localized numbness. His lower extremity strength and gait are relatively preserved. MRI reveals intramedullary signal changes at C4-C5 but no fracture. What is the most likely diagnosis?
. Anterior cord syndrome
. Brown-Séquard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Cruciate paralysis of Bell

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome is classically seen in older patients with cervical spondylosis who suffer a hyperextension injury. The mechanical pinch of the spinal cord leads to central gray and medial white matter damage, disproportionately affecting the upper extremities (especially hand dexterity) more than the lower extremities, as the cervical tracts are located more centrally.

Question 1548

Topic: Wrist & Carpus

A 65-year-old female presents with the sudden inability to actively extend her thumb interphalangeal joint 6 weeks after nonoperative treatment of a nondisplaced distal radius fracture. Radiographs show a healing fracture. What is the most appropriate definitive management?

. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer
. Primary end-to-end repair of the EPL tendon
. Extensor carpi radialis longus (ECRL) to EPL tendon transfer
. Cortisone injection into the third dorsal compartment
. Observation and passive range of motion therapy

Correct Answer & Explanation

. Extensor indicis proprius (EIP) to extensor pollicis longus (EPL) tendon transfer

Explanation

The patient has experienced a spontaneous rupture of the extensor pollicis longus (EPL) tendon, a known complication of nondisplaced distal radius fractures due to ischemia or mechanical attrition at Lister's tubercle. Because the tendon ends typically retract and undergo degeneration, primary repair is rarely possible. An EIP to EPL tendon transfer is the standard of care.

Question 1549

Topic: Wrist & Carpus
According to Mayfield's stages of progressive perilunate instability, what structural disruption defines Stage III of the cascade?
. Disruption of the scapholunate interosseous ligament
. Disruption of the lunotriquetral interosseous ligament
. Disruption of the radioscaphocapitate ligament
. Complete palmar dislocation of the lunate
. Dislocation of the capitate from the lunate without interosseous disruption

Correct Answer & Explanation

. Disruption of the lunotriquetral interosseous ligament

Explanation

The Mayfield classification describes the progressive perilunate instability cascade resulting from wrist hyperextension, ulnar deviation, and intercarpal supination. Stage I: Scapholunate interosseous ligament disruption. Stage II: Disruption of the capitolunate articulation. Stage III: Disruption of the lunotriquetral interosseous ligament (resulting in a perilunate dislocation). Stage IV: Failure of the dorsal radiocarpal ligament allowing the lunate to dislocate completely (usually volarly).

Question 1550

Topic: Wrist & Carpus

A 24-year-old male sustains an isolated distal-third radial shaft fracture (Galeazzi variant) and undergoes open reduction and internal fixation with a rigid compression plate. Intraoperatively, after anatomic fixation of the radius, the distal radioulnar joint (DRUJ) is tested. It remains grossly unstable in neutral and full pronation, but reliably reduces and remains perfectly stable in full supination. What is the most appropriate next step in management?

. Open repair of the triangular fibrocartilage complex (TFCC) through a dorsal approach
. Immobilization of the forearm in a long-arm splint or cast in full supination for 4 to 6 weeks
. Placement of a trans-articular radioulnar Kirschner wire followed by pronation casting
. Immediate ulnar shortening osteotomy to decompress the DRUJ
. Immobilization in a short-arm cast in neutral rotation

Correct Answer & Explanation

. Open repair of the triangular fibrocartilage complex (TFCC) through a dorsal approach

Explanation

A Galeazzi fracture involves a distal radius shaft fracture with disruption of the distal radioulnar joint (DRUJ). The primary treatment is rigid anatomic internal fixation of the radius. If the DRUJ is unstable post-fixation, its stability should be assessed in supination. Supination functionally closes the DRUJ by tightening the palmar radioulnar ligaments and reducing the ulna dorsally into the sigmoid notch. If the DRUJ is stable in full supination, the standard of care is nonoperative management of the DRUJ using a long-arm cast or splint in supination for 4-6 weeks. Operative intervention (pinning or TFCC repair) is reserved for DRUJ instability that persists even in full supination.

Question 1551

Topic: 7. Hand and Wrist
The vascularity of the digital flexor tendons is significantly richer in what cross-sectional region?
. Volar ulnar quadrant
. Volar radial quadrant
. Peripheral one third
. Dorsal one half
. Center

Correct Answer & Explanation

. Dorsal one half

Explanation

DISCUSSION: The vascularity of the dorsal portion of the digital flexor tendons is considerably richer than the volar portion. The other regions are not preferentially more vascular. REFERENCES: Hunter JM, Scheider LH, Makin EJ (eds): Tendon Surgery in the Hand. St Louis, MO, Mosby, 1987, pp 91-99. Gelberman RH, Khabie V, Cahill CJ: The revascularization on healing flexor tendons in the digital sheath: A vascular injection study in dogs. J Bone Joint Surg Am 1991;73:868-881.

Question 1552

Topic: 7. Hand and Wrist
When performing a flexor tendon repair of a digit other than the thumb, what structures of the flexor tendon sheath should be preserved?
. A1 and A2 pulleys
. A1 and A3 pulleys
. A2 and A3 pulleys
. A2 and A4 pulleys
. C1 and C2 pulleys

Correct Answer & Explanation

. A2 and A4 pulleys

Explanation

The A2 and A4 pulleys are considered the most important parts of the pulley system. If these two structures are preserved, 80% of finger flexion can be maintained. If the pulley system is not left intact or is not reconstructed, bow-stringing of the flexor tendons occurs with loss of full flexion. The A2 pulley is over the proximal phalanx and the A4 pulley is over the middle phalanx.

Question 1553

Topic: 7. Hand and Wrist

A professional football player sustains an extreme hyperextension injury to the first metatarsophalangeal (MTP) joint, resulting in a Grade 3 'turf toe' injury with frank dorsal dislocation of the proximal phalanx. Which of the following anatomic structures is consistently completely ruptured in a true Grade 3 turf toe injury?

. Extensor hallucis longus tendon
. Plantar plate and sesamoid complex
. Medial collateral ligament only
. Dorsal capsule
. Flexor hallucis longus tendon

Correct Answer & Explanation

. Extensor hallucis longus tendon

Explanation

Turf toe is a severe sprain of the first MTP joint caused by an axial load on a dorsiflexed toe. A Grade 3 injury involves a complete tear of the plantar plate and the sesamoid complex (often disrupting the sesamoid phalangeal ligaments), leading to frank instability or dislocation. Surgical repair is often indicated for Grade 3 injuries, especially in elite athletes.

Question 1554

Topic: 7. Hand and Wrist

A collegiate football lineman hyperextends his great toe on artificial turf. He presents with severe pain, ecchymosis, and an inability to push off. MRI reveals a complete rupture of the plantar plate and capsular ligamentous complex from the proximal phalanx. According to the Anderson classification, what grade is this injury, and what is the typical recommendation?

. Grade 1; conservative treatment
. Grade 2; conservative treatment
. Grade 3; surgical repair
. Grade 3; conservative treatment initially
. Grade 4; immediate fusion

Correct Answer & Explanation

. Grade 1; conservative treatment

Explanation

Turf toe is a sprain or tear of the first MTP joint plantar plate. The Anderson Classification grades them as: Grade 1 (stretch), Grade 2 (partial tear), and Grade 3 (complete tear with loss of continuity of the plantar plate). Grade 3 injuries in competitive athletes—especially those with MTP instability, gross deformity, or sesamoid retraction—often require surgical repair to restore push-off strength and prevent chronic instability.

Question 1555

Topic: 7. Hand and Wrist
A 68-year-old man with known cervical spondylosis slips on ice, striking his forehead and forcing his neck into sudden hyperextension. He presents to the ED with burning pain in his upper extremities and severe weakness in his hands and arms. His leg strength is 4/5 bilaterally, and he is able to ambulate with assistance. Perianal sensation is intact. What is the most likely diagnosis?
. Anterior cord syndrome
. Brown-Séquard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome typically occurs in older patients with pre-existing cervical spondylosis who sustain a hyperextension injury. The classical presentation is motor weakness that is more severe in the upper extremities than in the lower extremities, often accompanied by burning dysesthesias in the hands. The centrally located cervical tracts for the upper extremities are preferentially injured.

Question 1556

Topic: 7. Hand and Wrist

A 42-year-old man complains of radiating right arm pain. Examination shows weakness in wrist flexion and triceps extension, decreased sensation over the middle finger, and an absent triceps reflex. Which cervical nerve root is most likely compressed?

. C5
. C6
. C7
. C8
. T1

Correct Answer & Explanation

. C5

Explanation

The C7 nerve root supplies the triceps, wrist flexors, and finger extensors. It provides sensation to the middle finger and mediates the triceps reflex.

Question 1557

Topic: 7. Hand and Wrist
A newborn is noted to have a congenital hemivertebra at T8 causing early scoliotic deformity. Which of the following screening tests is most critical in the initial workup of this patient to rule out associated anomalies?
. Renal ultrasound
. Brain MRI
. Pulmonary function testing
. Lower extremity Doppler ultrasound
. Serum thyroid panel

Correct Answer & Explanation

. Renal ultrasound

Explanation

Congenital scoliosis is frequently associated with VACTERL sequence anomalies. Renal ultrasound and echocardiography are critical early screening tests to rule out associated genitourinary and cardiac defects.

Question 1558

Topic: 7. Hand and Wrist
A 28-year-old anesthesia resident has aching pain in his dominant right forearm after injuring it while playing basketball 1 week ago. He reports that he is unable to perform regional anesthesia that requires manipulation of a needle. Examination reveals that he is unable to flex the interphalangeal joint of the thumb, and flexion of the distal interphalangeal joint of the index finger is weak. Management should consist of
. stretching of the forearm in pronation, wrist flexion, and splinting.
. primary tendon repair of the flexor pollicis longus and flexor digitorum profundus to the index finger, followed by immobilization.
. electrodiagnostic examination, followed by decompression of the anterior interosseous nerve within the next 2 to 3 weeks.
. splinting followed by observation; surgical decompression of the median nerve may be required if no improvement in seen in 3 months.
. splinting followed by observation; surgical decompression of the anterior interosseous nerve may be required if no improvement is seen in 6 months.

Correct Answer & Explanation

. splinting followed by observation; surgical decompression of the anterior interosseous nerve may be required if no improvement is seen in 6 months.

Explanation

The patient has anterior interosseous nerve palsy. Initial management should consist of splinting followed by observation; surgical decompression may be required if there is no improvement in the functional deficit in 6 months. Anterior interosseous nerve palsy is classically described as an inability to flex the interphalangeal joint of the thumb because of flexor pollicis longus paralysis and a weakness or inability to flex the distal interphalangeal joint of the index finger because of weakness and/or paralysis of the flexor digitorum profundus to the index finger. Recent recommendations have been to extend the period of observation from 3 to 6 months before surgical decompression, as most cases will resolve within 6 months.

Question 1559

Topic: 7. Hand and Wrist
The most common mechanism of injury to the triangular fibrocartilage complex (TFCC) involves
. wrist extension and forearm pronation.
. wrist extension and forearm supination.
. wrist flexion and forearm pronation.
. wrist flexion and forearm supination.
. axial load in ulnar deviation.

Correct Answer & Explanation

. wrist extension and forearm pronation.

Explanation

TFCC tears are common in athletes. As the athlete braces for a fall, the wrist is most commonly in an extended position and the forearm is pronated.

Question 1560

Topic: 7. Hand and Wrist

A 62-year-old woman presents with sudden inability to actively flex the interphalangeal joint of her right thumb 8 months after undergoing open reduction and internal fixation of a distal radius fracture with a volar locking plate. What is the most likely cause of her current presentation?

. Extensor pollicis longus (EPL) attrition due to dorsal screw prominence
. Flexor pollicis longus (FPL) rupture due to placement of the plate distal to the watershed line
. Median nerve compression within the carpal tunnel
. Nonunion of the distal radius fracture leading to secondary tendon rupture
. Anterior interosseous nerve (AIN) palsy

Correct Answer & Explanation

. Extensor pollicis longus (EPL) attrition due to dorsal screw prominence

Explanation

Attritional rupture of the flexor pollicis longus (FPL) tendon is a classic and severe complication of volar locking plates used for distal radius fractures. It most commonly occurs when the plate is positioned too far distally, crossing the 'watershed line' of the distal radius, which exposes the tendon to repetitive friction against the prominent distal edge of the plate.

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