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7. Hand and Wrist MCQs

Practice Set 250 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 4981

Topic: 7. Hand and Wrist
A carpenter sustains a deep laceration over the palmar aspect of his proximal phalanx of the ring finger, completely severing both the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP). This injury is anatomically located in which flexor tendon zone?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II (historically called "no man's land") extends from the A1 pulley (distal palmar crease) to the insertion of the FDS on the middle phalanx. Injuries here involve both the FDS and FDP tendons within a tight fibro-osseous sheath.

Question 4982

Topic: 7. Hand and Wrist

In flexor tendon repair of the hand, which of the following intraoperative factors is the most critical determinant of the initial mechanical strength of the repair?

. The type of continuous epitendinous suture used
. The number of core suture strands crossing the repair site
. The caliber of the needle used for the core suture
. The degree of volar wrist flexion post-operatively
. The strict excision of the flexor sheath at the repair site

Correct Answer & Explanation

. The number of core suture strands crossing the repair site

Explanation

The initial biomechanical strength of a flexor tendon repair is directly proportional to the number of core suture strands crossing the repair site. Modern protocols typically require a 4-strand or 6-strand repair to safely withstand the forces of early active motion.

Question 4983

Topic: 7. Hand and Wrist

A 45-year-old female develops allodynia, stiffness, and skin color changes in her hand after a distal radius fracture. A triple-phase bone scintigraphy scan is obtained to evaluate for Complex Regional Pain Syndrome (CRPS). What is the classic finding on bone scan in this condition?

. Decreased uptake in all three phases of the scan
. Increased periarticular uptake isolated to the delayed phase
. Diffuse increased uptake in phase 3 with rapid washout
. Increased periarticular uptake diffusely across all three phases
. Focal cold spots corresponding to the primary fracture site

Correct Answer & Explanation

. Increased periarticular uptake diffusely across all three phases

Explanation

The classic scintigraphic finding in CRPS is diffusely increased periarticular radiotracer uptake across all three phases of a technetium bone scan in the affected limb, signifying altered local hemodynamics and bone turnover.

Question 4984

Topic: 7. Hand and Wrist

During an extensive tenolysis of the flexor digitorum profundus in zone 2 of the hand, which of the following annular pulleys are considered biomechanically crucial to preserve to prevent bowstringing of the tendon?

. A1 and A3
. A2 and A4
. A3 and A5
. A1 and A5
. A2 and A3

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 pulley (located over the proximal phalanx) and the A4 pulley (located over the middle phalanx) are the most critical annular pulleys biomechanically. Preserving or reconstructing them is essential to prevent bowstringing of the flexor tendons and maintain the functional moment arm for digit flexion.

Question 4985

Topic: 7. Hand and Wrist

Which of the following clinical findings best differentiates Pronator Syndrome from Carpal Tunnel Syndrome on physical examination?

. Numbness in the first three digits
. Weakness of the abductor pollicis brevis
. Positive Tinel's sign at the wrist
. Numbness over the thenar eminence
. Nighttime awakening with paresthesias

Correct Answer & Explanation

. Numbness over the thenar eminence

Explanation

The palmar cutaneous branch of the median nerve arises approximately 5 cm proximal to the wrist crease and travels superficial to the carpal tunnel to supply sensation to the thenar eminence. Therefore, numbness over the thenar eminence occurs in proximal median nerve compression (such as Pronator syndrome) but is spared in Carpal Tunnel Syndrome.

Question 4986

Topic: Wrist & Carpus

A 30-year-old male sustains a Galeazzi fracture-dislocation. Following rigid internal fixation of the radial shaft, the distal radioulnar joint (DRUJ) remains unstable in neutral rotation. In which position is the DRUJ typically most stable and thus recommended for postoperative immobilization?

. Pronation
. Supination
. Neutral rotation
. Palmar flexion
. Dorsiflexion

Correct Answer & Explanation

. Supination

Explanation

A Galeazzi fracture involves the distal third of the radius with disruption of the DRUJ. Following internal fixation of the radius, the DRUJ is evaluated. It is typically most stable in supination because the palmar radioulnar ligament (the primary stabilizer in supination) and the intact interosseous membrane are tensioned, reducing the ulnar head into the sigmoid notch.

Question 4987

Topic: 7. Hand and Wrist

A 22-year-old male sustains a proximal pole scaphoid fracture. The high risk of avascular necrosis in this fracture pattern is directly related to the retrograde blood supply of the scaphoid. This blood supply primarily arises from which of the following vessels?

. Volar carpal branch of the radial artery
. Dorsal carpal branch of the radial artery
. Volar branch of the ulnar artery
. Superficial palmar arch
. Deep palmar arch

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The primary blood supply to the scaphoid (supplying the proximal 70-80% of the bone) comes from the dorsal carpal branch of the radial artery, which enters at the dorsal ridge near the scaphoid waist and flows in a retrograde fashion toward the proximal pole.

Question 4988

Topic: 7. Hand and Wrist
A 45-year-old manual laborer presents with chronic radial-sided wrist pain. Radiographs show a scaphoid nonunion with arthritic changes exclusively between the distal scaphoid fragment and the radial styloid. The midcarpal joint and radiolunate joint are preserved. This represents SNAC stage I. What is the most appropriate surgical intervention?
. Proximal row carpectomy
. Four-corner fusion with scaphoid excision
. Radial styloidectomy and scaphoid nonunion takedown with bone grafting
. Total wrist arthrodesis
. Scaphoid excision alone

Correct Answer & Explanation

. Radial styloidectomy and scaphoid nonunion takedown with bone grafting

Explanation

Scaphoid Nonunion Advanced Collapse (SNAC) stage I involves isolated arthritis between the distal scaphoid pole and the radial styloid. Treatment typically consists of a radial styloidectomy to address the localized arthritis, combined with scaphoid ORIF and bone grafting to heal the nonunion. PRC or 4-corner fusion are salvage procedures reserved for Stages II and III.

Question 4989

Topic: 7. Hand and Wrist

A 28-year-old chef sustains a deep laceration to the volar aspect of his index finger at the level of the proximal phalanx, resulting in an inability to flex the PIP and DIP joints. This injury occurred in Flexor Tendon Zone II. What anatomical boundaries define this zone?

. From the FDS insertion to the FDP insertion
. From the proximal edge of the A1 pulley to the FDS insertion
. From the carpal tunnel to the distal palmar crease
. From the musculotendinous junction to the carpal tunnel
. From the FDP insertion to the distal tip of the phalanx

Correct Answer & Explanation

. From the proximal edge of the A1 pulley to the FDS insertion

Explanation

Zone II (historically termed 'No Man\'s Land') of the flexor tendons extends from the proximal margin of the A1 pulley (roughly corresponding to the distal palmar crease) to the insertion of the flexor digitorum superficialis (FDS) at the middle phalanx. It is notorious for difficult repairs due to the tight fibro-osseous canal and risk of dense adhesions.

Question 4990

Topic: Nerve & Tendon

A 35-year-old avid cyclist complains of numbness in his ring and small fingers, and weakness with finger abduction. However, he has completely normal sensation over the dorso-ulnar aspect of his hand. Examination reveals a positive Froment's sign. Where is the most likely anatomic site of neural compression?

. Cubital tunnel
. Guyon's canal
. Arcade of Struthers
. Between the two heads of flexor carpi ulnaris
. C8 nerve root foramen

Correct Answer & Explanation

. Guyon's canal

Explanation

The dorsal ulnar cutaneous nerve branches off the main ulnar nerve proximal to the wrist (roughly 5-8 cm proximal to the ulnar styloid). Preservation of dorso-ulnar sensation with concurrent ulnar motor (positive Froment's sign) and sensory deficits in the palmar digits indicates a distal lesion, classically at Guyon's canal ('cyclist\'s palsy'). Compression at the elbow (cubital tunnel) would typically affect the dorsal sensory branch.

Question 4991

Topic: 7. Hand and Wrist
A 35-year-old male presents with progressive wrist pain years after an untreated scaphoid waist fracture. Radiographs show a scaphoid nonunion advanced collapse (SNAC). Imaging demonstrates arthritic changes at the radioscaphoid joint, and between the scaphoid, capitate, and lunate. Which joint typically remains spared in the late stages of SNAC wrist, making the patient a candidate for a four-corner fusion?
. Radioscaphoid joint
. Capitolunate joint
. Radiolunate joint
. Scaphotrapezial joint
. Scaphotrapezoideal joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In Scaphoid Nonunion Advanced Collapse (SNAC), the normal kinematics of the wrist are disrupted, leading to progressive arthritis. The arthritis typically starts at the radioscaphoid joint (Stage I), progresses to the scaphocapitate joint (Stage II), and then to the capitolunate joint (Stage III). The radiolunate joint is characteristically spared, because the lunate remains concentrically located in the lunate fossa of the radius. This preservation allows for a motion-preserving salvage procedure such as a proximal row carpectomy (PRC) or a four-corner fusion.

Question 4992

Topic: 7. Hand and Wrist

A 45-year-old typist is undergoing an open carpal tunnel release. To avoid injury to the recurrent motor branch of the median nerve, the surgeon must be aware of its most common anatomical variation. The recurrent branch typically innervates which of the following muscle groups?

. Hypothenar muscles
. First and second lumbricals
. Thenar muscles
. Adductor pollicis
. Dorsal interossei

Correct Answer & Explanation

. Thenar muscles

Explanation

The recurrent motor branch of the median nerve supplies the thenar muscles: the abductor pollicis brevis, opponens pollicis, and the superficial head of the flexor pollicis brevis. (The deep head of FPB and adductor pollicis are supplied by the ulnar nerve). During carpal tunnel release, recognizing its course is critical to prevent iatrogenic thenar denervation.

Question 4993

Topic: Wrist & Carpus

A 45-year-old patient undergoing an open reduction internal fixation of a distal radius fracture under an axillary block suddenly develops perioral numbness, tinnitus, tonic-clonic seizures, and subsequent cardiovascular collapse. Intravenous 20% lipid emulsion therapy is rapidly initiated. What was the most likely regional anesthetic agent used?

. Lidocaine
. Bupivacaine
. Ropivacaine
. Mepivacaine
. Chloroprocaine

Correct Answer & Explanation

. Bupivacaine

Explanation

The presentation is classic for local anesthetic systemic toxicity (LAST). Bupivacaine is a highly lipophilic, long-acting amide local anesthetic with a strong affinity for cardiac voltage-gated sodium channels. This strong binding makes it profoundly cardiotoxic compared to other agents. Intravenous lipid emulsion acts as a 'lipid sink' to draw the lipophilic bupivacaine away from the myocardium and central nervous system.

Question 4994

Topic: Wrist & Carpus

Which of the following pharmacological agents has been shown in prospective randomized trials to significantly decrease the incidence of Complex Regional Pain Syndrome (CRPS) following closed treatment of distal radius fractures?

. Gabapentin
. Pregabalin
. Vitamin C (Ascorbic acid)
. Ibuprofen
. Amitriptyline

Correct Answer & Explanation

. Vitamin C (Ascorbic acid)

Explanation

Vitamin C (ascorbic acid), typically given at a dose of 500 mg daily for 50 days following injury, has been shown in several randomized controlled trials to significantly reduce the risk of developing Complex Regional Pain Syndrome (CRPS) after distal radius fractures.

Question 4995

Topic: 7. Hand and Wrist

A 45-year-old mechanic complains of chronic vague pain in the dorsal proximal forearm and weakness when extending his fingers and thumb, though wrist extension is largely preserved. He has no sensory deficits. The affected nerve is most likely compressed by which of the following structures?

. Ligament of Struthers
. Lacertus fibrosus
. Arcade of Frohse
. Osborne's ligament
. Pronator teres heads

Correct Answer & Explanation

. Arcade of Frohse

Explanation

The patient has Posterior Interosseous Nerve (PIN) syndrome, characterized by weakness in finger/thumb extension and preserved radial wrist extension. The most common site of PIN compression is the Arcade of Frohse, the proximal fascial edge of the superficial head of the supinator muscle.

Question 4996

Topic: 7. Hand and Wrist

A patient cannot actively extend the interphalangeal joint of the thumb following a stab wound to the dorsal proximal forearm. Sensation in the hand is completely intact. Which nerve is most likely injured?

. Superficial branch of the radial nerve
. Posterior interosseous nerve
. Anterior interosseous nerve
. Ulnar nerve
. Median nerve

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

The Posterior Interosseous Nerve (PIN) innervates the extensor pollicis longus (EPL), which extends the IP joint of the thumb. The PIN is a purely motor branch of the radial nerve; therefore, its injury causes motor deficits (such as thumb and finger drop) without any sensory loss.

Question 4997

Topic: Nerve & Tendon

A patient with advanced rheumatoid arthritis presents with a classic swan neck deformity of the ring finger. This specific deformity is morphologically defined by which of the following joint positions?

. Flexion of the PIP joint and extension of the DIP joint
. Extension of the MCP joint and flexion of the PIP joint
. Hyperextension of the PIP joint and flexion of the DIP joint
. Flexion of both the PIP and DIP joints
. Hyperextension of both the PIP and DIP joints

Correct Answer & Explanation

. Hyperextension of the PIP joint and flexion of the DIP joint

Explanation

A swan neck deformity consists of proximal interphalangeal (PIP) joint hyperextension combined with distal interphalangeal (DIP) joint flexion. It is typically initiated by volar plate attenuation at the PIP joint or extreme intrinsic muscle tightness.

Question 4998

Topic: 7. Hand and Wrist

A 40-year-old female presents with aching pain in her proximal forearm and paresthesias in the radial three-and-a-half digits. Symptoms are not exacerbated by wrist flexion but worsen with resisted forearm pronation. Which of the following physical exam findings best differentiates this condition from carpal tunnel syndrome?

. Tinel's sign at the wrist
. Decreased sensation over the thenar eminence
. Weakness of the flexor pollicis longus
. Positive Phalen's test
. Atrophy of the abductor pollicis brevis

Correct Answer & Explanation

. Decreased sensation over the thenar eminence

Explanation

The palmar cutaneous branch of the median nerve branches off proximal to the carpal tunnel and supplies sensation to the thenar eminence. In Pronator Syndrome (proximal median nerve compression), sensation over the thenar eminence is decreased. In Carpal Tunnel Syndrome, this branch is spared, and thenar sensation is normal.

Question 4999

Topic: 7. Hand and Wrist
A 30-year-old carpenter lacerates his index finger over the middle phalanx, dividing both the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons. Based on the Verdan flexor tendon zone classification, in which zone did this injury occur?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II extends from the proximal edge of the A1 pulley (distal palmar crease) to the insertion of the FDS on the middle phalanx. It contains both the FDS and FDP tendons within the tight fibro-osseous sheath. Historically known as 'no man's land', lacerations here require meticulous repair.

Question 5000

Topic: Nerve & Tendon

A 6-year-old girl sustains a widely displaced extension-type supracondylar humerus fracture. Upon reduction and pinning, she is unable to flex her thumb interphalangeal joint or index finger distal interphalangeal joint. Which nerve is most likely injured?

. Median nerve (main branch)
. Anterior interosseous nerve
. Posterior interosseous nerve
. Ulnar nerve
. Radial nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar humerus fractures. It classically presents with the inability to form an "OK" sign due to weakness of the FPL and FDP to the index finger.

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