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7. Hand and Wrist MCQs

Practice Set 221 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 4401

Topic: 7. Hand and Wrist

Which of the following radiographic features reliably differentiates a Stage II SNAC wrist from a Stage II SLAC wrist?

. Advanced arthritis at the radiolunate articulation
. Preservation of the proximal radioscaphoid articulation
. Dorsal subluxation of the capitate
. Ulnar translocation of the entire carpus
. Arthritis extending to the trapeziometacarpal joint

Correct Answer & Explanation

. Advanced arthritis at the radiolunate articulation

Explanation

In a SNAC wrist, the proximal scaphoid pole remains attached to the lunate via the intact scapholunate ligament, preserving the congruent proximal radioscaphoid joint. In a SLAC wrist, the entire scaphoid subluxates, leading to arthritis involving the entire radioscaphoid fossa by Stage II.

Question 4402

Topic: 7. Hand and Wrist

When comparing proximal row carpectomy (PRC) to scaphoid excision and four-corner arthrodesis (FCA) for the salvage of a SNAC wrist, long-term outcome studies generally demonstrate that PRC offers which of the following advantages?

. Significantly higher postoperative grip strength
. A lower rate of subsequent osteoarthritis requiring total wrist fusion
. Shorter operative time, lack of hardware, and equivalent patient-reported outcomes
. Preservation of the midcarpal joint allowing for pure dart thrower's motion
. Complete avoidance of radiocarpal impingement

Correct Answer & Explanation

. Significantly higher postoperative grip strength

Explanation

PRC is technically simpler, avoids hardware complications, requires less immobilization, and has a lower nonunion rate compared to FCA. Both procedures provide comparable pain relief, grip strength, and range of motion, though FCA has traditionally been favored for younger laborers due to theoretical durability.

Question 4403

Topic: 7. Hand and Wrist
A patient undergoes a four-corner arthrodesis for SNAC Stage III. Which kinematic function of the wrist will be most significantly altered or abolished compared to a native wrist?
. Radioulnar deviation at the radiocarpal joint
. Dart thrower's motion, due to obliteration of the midcarpal joint
. Forearm supination and pronation
. Flexion at the radiolunate articulation
. Extension at the radiolunate articulation

Correct Answer & Explanation

. Dart thrower's motion, due to obliteration of the midcarpal joint

Explanation

Dart thrower's motion (oblique movement from radial extension to ulnar flexion) occurs primarily at the midcarpal joint. A four-corner arthrodesis fuses the midcarpal joint, significantly limiting this highly functional oblique motion.

Question 4404

Topic: 7. Hand and Wrist

A surgeon elects to use a pedicled vascularized bone graft from the volar distal radius to treat a scaphoid nonunion with a volar deformity. This specific graft (often called the Kaji graft) is typically supplied by which of the following arteries?

. Pronator quadratus branch of the anterior interosseous artery
. Volar carpal branch of the radial artery
. Superficial palmar branch of the radial artery
. Dorsal carpal arch
. Recurrent radial artery

Correct Answer & Explanation

. Pronator quadratus branch of the anterior interosseous artery

Explanation

The volar pedicled bone graft from the distal radius (Kaji graft) is vascularized by the volar carpal artery, a branch of the radial artery. It is particularly useful for volar approaches when correcting a humpback deformity simultaneously.

Question 4405

Topic: 7. Hand and Wrist
A 45-year-old mechanic presents with chronic wrist pain. Radiographs reveal a scaphoid nonunion with radioscaphoid and capitolunate joint space narrowing. The radiolunate joint is well-preserved, but the capitate head demonstrates severe subchondral sclerosis and cyst formation. Which of the following is the most appropriate surgical intervention?
. Proximal row carpectomy
. Total wrist arthrodesis
. Scaphoid excision and four-corner fusion
. Radial styloidectomy and scaphoid ORIF
. Scaphoid excision and triquetrum excision

Correct Answer & Explanation

. Scaphoid excision and four-corner fusion

Explanation

This patient has SNAC Stage III wrist arthropathy. Because the capitate head is arthritic, a proximal row carpectomy is contraindicated; however, an intact radiolunate joint makes scaphoid excision and four-corner fusion the ideal salvage procedure.

Question 4406

Topic: Nerve & Tendon

A 12-year-old boy sustains an elbow dislocation. After closed reduction in the emergency department, a post-reduction radiograph shows the ulnohumeral joint is concentrically reduced, but there is a displaced medial epicondyle fracture. What is an absolute indication for open reduction and internal fixation of this fracture?

. Displacement > 2 mm
. Incarceration of the medial epicondyle fragment within the ulnohumeral joint
. Patient participation in overhead throwing sports
. Concomitant nondisplaced radial neck fracture
. Positive Tinel's sign at the cubital tunnel

Correct Answer & Explanation

. Displacement > 2 mm

Explanation

Absolute indications for operative intervention (ORIF) of a medial epicondyle fracture include incarceration of the fracture fragment within the joint (often recognized by a non-concentric reduction or visible fragment on post-reduction X-ray) and an open fracture. Entrapment of the ulnar nerve is also considered an absolute or strong relative indication. Displacement > 5-15 mm and high-demand overhead athletic activity are debated relative indications.

Question 4407

Topic: 7. Hand and Wrist

In the management of flexor tendon lacerations, 'Zone II' is classically known as 'No Man's Land' due to historically poor surgical outcomes. What are the anatomical boundaries of flexor tendon Zone II?

. Distal to the FDS insertion to the FDP insertion
. From the proximal edge of the A1 pulley to the FDS insertion
. From the distal edge of the carpal tunnel to the A1 pulley
. From the musculotendinous junction to the proximal carpal tunnel
. Distal to the FDP insertion

Correct Answer & Explanation

. Distal to the FDS insertion to the FDP insertion

Explanation

Zone II of the flexor tendons extends from the proximal edge of the A1 pulley (at the distal palmar crease) to the insertion of the Flexor Digitorum Superficialis (FDS) at the middle phalanx. Both FDS and FDP travel within the narrow fibro-osseous sheath here, making repair technically demanding and highly prone to adhesion formation.

Question 4408

Topic: Wrist & Carpus

A 65-year-old woman undergoes volar plate fixation for a displaced distal radius fracture. Six months postoperatively, she presents complaining of a sudden inability to bend the tip of her thumb. What is the most likely cause of this complication?

. Attritional rupture of the flexor pollicis longus (FPL) tendon
. Iatrogenic injury to the anterior interosseous nerve
. Unrecognized injury to the recurrent motor branch of the median nerve
. Nonunion of the distal radius
. Rupture of the extensor pollicis longus (EPL) tendon

Correct Answer & Explanation

. Attritional rupture of the flexor pollicis longus (FPL) tendon

Explanation

Volar plating of the distal radius places the flexor tendons, particularly the FPL, at risk for attritional rupture if the plate is positioned distal to the watershed line of the distal radius. The loss of active interphalangeal flexion of the thumb characterizes an FPL rupture. EPL rupture is more common after nonoperative management or dorsal plating of distal radius fractures.

Question 4409

Topic: 7. Hand and Wrist
A mechanic sustains a deep knife laceration over the volar aspect of the proximal phalanx of his ring finger. Examination reveals an inability to actively flex both the PIP and DIP joints of that finger. This injury is located in which anatomical flexor tendon zone?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

The flexor tendon zones of the hand define the anatomical location of injury. Zone II (historically called 'no man's land') extends from the proximal edge of the A1 pulley (distal palmar crease) to the insertion of the Flexor Digitorum Superficialis (FDS) on the middle phalanx. The volar aspect of the proximal phalanx is strictly within Zone II, containing both the FDS and FDP tendons.

Question 4410

Topic: 7. Hand and Wrist
A 70-year-old male with pre-existing cervical spondylosis presents after a hyperextension injury to his neck during a motor vehicle collision. On examination, he has significant weakness in his bilateral hands and arms (1/5 strength), but retains 4/5 strength in his legs. Perianal sensation is intact. What is the most likely diagnosis?
. Anterior cord syndrome
. Brown-Sรฉquard syndrome
. Central cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Central cord syndrome

Explanation

Central cord syndrome typically occurs after a hyperextension injury in older patients with cervical spondylosis. It classically presents with motor weakness that is more pronounced in the upper extremities than in the lower extremities, along with varying degrees of sensory loss. The sacral tracts (perianal sensation) are peripherally located and typically spared.

Question 4411

Topic: 7. Hand and Wrist

A 25-year-old carpenter lacerates his volar index finger at the level of the proximal phalanx, resulting in an inability to flex the proximal and distal interphalangeal joints. During surgical exploration, repair of the flexor tendon sheath pulleys is considered to prevent biomechanical failure (bowstringing). Which two pulleys are most critical to preserve or reconstruct?

. A1 and A3
. A2 and A4
. A3 and A5
. C1 and C2
. A1 and A5

Correct Answer & Explanation

. A1 and A3

Explanation

The A2 (arising from the proximal phalanx) and A4 (arising from the middle phalanx) pulleys are biomechanically the most important annular pulleys in the flexor tendon sheath. Preserving or reconstructing them is crucial to prevent tendon bowstringing and ensure an effective excursion for finger flexion.

Question 4412

Topic: 7. Hand and Wrist
A 30-year-old carpenter suffers a deep laceration over the volar aspect of his proximal phalanx. He is unable to flex the proximal or distal interphalangeal joints of his index finger. This injury occurred in which flexor tendon zone?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

The injury involves both the FDS and FDP tendons over the proximal phalanx, which corresponds to Zone II. This area is traditionally known as "no man's land" due to the historical difficulty of successful surgical repair and risk of adhesion.

Question 4413

Topic: Nerve & Tendon

A patient presents with intrinsic hand weakness, clawing of the ring and small fingers, and numbness in the ulnar half of the ring finger. Froment's sign is positive. The examiner suspects compressive ulnar neuropathy. Which of the following anatomical structures is NOT a recognized site of ulnar nerve compression at or around the elbow?

. Arcade of Struthers
. Osborne's ligament
. Arcade of Frohse
. Fascial aponeurosis of the two heads of the flexor carpi ulnaris (FCU)
. Medial intermuscular septum

Correct Answer & Explanation

. Arcade of Struthers

Explanation

Ulnar nerve entrapment around the elbow (Cubital Tunnel Syndrome) can occur at several classic sites: the Arcade of Struthers (typically ~8cm proximal to the medial epicondyle), the medial intermuscular septum, the medial epicondyle, Osborne's ligament (the retinaculum bridging the two heads of the FCU), and the deep flexor-pronator aponeurosis. The Arcade of Frohse is the fibrous proximal edge of the superficial layer of the supinator muscle; it is the most common site of compression for the Posterior Interosseous Nerve (PIN), a branch of the radial nerve, NOT the ulnar nerve.

Question 4414

Topic: Nerve & Tendon

A surgeon is performing a release of the first dorsal extensor compartment for recalcitrant De Quervain's tenosynovitis. Incomplete release is a known cause of persistent postoperative symptoms. Which of the following anatomic variations within the first compartment is most commonly responsible for this failure?

. An aberrant superficial branch of the radial nerve piercing the extensor retinaculum
. A separate fibrous subsheath enclosing the Extensor Pollicis Brevis (EPB) tendon
. A duplicated Abductor Pollicis Longus (APL) tendon situated dorsally
. Failure to release the adjacent Extensor Pollicis Longus (EPL) tendon
. A proximal muscular intersection with the Extensor Carpi Radialis Longus (ECRL)

Correct Answer & Explanation

. An aberrant superficial branch of the radial nerve piercing the extensor retinaculum

Explanation

De Quervain's tenosynovitis is a stenosing tenosynovitis of the first dorsal compartment, which contains the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) tendons. A very common anatomic variation is the presence of a distinct fibrous septum that creates a separate subsheath for the EPB tendon, occurring in up to 30-40% of patients. During surgical release, if the surgeon opens the main compartment (usually finding multiple slips of the APL) but fails to recognize and open the hidden separate EPB subsheath, the EPB remains tethered, leading to persistent symptoms and surgical failure. While APL multiple slips are common, failure to recognize the EPB subsheath is the primary cause of inadequate release.

Question 4415

Topic: Wrist & Carpus

A 60-year-old female presents with an inability to flex the interphalangeal joint of her right thumb. She underwent open reduction and internal fixation of a distal radius fracture using a volar locking plate 6 months ago. What is the most likely pathophysiological cause of this complication?

. The plate was placed proximal to the watershed line
. A prominently long screw tip protruding through the dorsal cortex
. The plate was placed distal to the watershed line
. Iatrogenic transection of the flexor pollicis longus tendon during the initial surgical approach
. Attritional rupture of the extensor pollicis longus tendon

Correct Answer & Explanation

. The plate was placed proximal to the watershed line

Explanation

Attritional rupture of the flexor pollicis longus (FPL) tendon is a well-documented complication of volar plating of the distal radius. This typically occurs when the plate is positioned too far distally, crossing the 'watershed line' (the distal margin of the pronator fossa), which causes the FPL tendon to rub directly against the prominent distal edge of the plate during finger movement.

Question 4416

Topic: 7. Hand and Wrist
A sharp laceration of the volar hand involves complete transection of both the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons at the level of the base of the middle phalanx. According to the Verdan classification, which flexor tendon zone is injured?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II, historically termed 'no man's land', extends from the proximal edge of the A1 pulley (at the distal palmar crease) to the insertion of the FDS tendon on the middle phalanx. Injuries in this zone involve both FDS and FDP tendons within the tight fibro-osseous flexor sheath.

Question 4417

Topic: 7. Hand and Wrist
A 30-year-old carpenter sustains a deep glass laceration to the palmar aspect of his index finger proximal phalanx. He is unable to actively flex both the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints. This injury corresponds to which flexor tendon zone?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II (often historically called 'no man's land') extends from the distal palmar crease (A1 pulley) to the insertion of the flexor digitorum superficialis (FDS). Lacerations here commonly involve both the FDS and FDP tendons.

Question 4418

Topic: Nerve & Tendon

When evaluating a patient with an ulnar nerve injury, the 'ulnar paradox' refers to which of the following clinical phenomena?

. A proximal (high) injury results in more severe digital clawing than a distal injury
. A proximal (high) injury results in less severe digital clawing than a distal (low) injury
. Intrinsic muscle wasting is spared in distal injuries
. A low injury paradoxically causes median nerve territory numbness
. A high injury selectively spares the flexor digitorum profundus (FDP)

Correct Answer & Explanation

. A proximal (high) injury results in more severe digital clawing than a distal injury

Explanation

The 'ulnar paradox' dictates that a proximal ulnar nerve lesion (at the elbow) denervates the FDP to the ring and small fingers, thereby reducing the active flexion force at the DIP joints and resulting in a less pronounced claw deformity compared to a distal wrist lesion.

Question 4419

Topic: 7. Hand and Wrist
During an open carpal tunnel release, the surgeon notes a motor branch of the median nerve exiting the ulnar aspect of the main nerve trunk and crossing superficially over the flexor retinaculum to innervate the thenar muscles. Which anatomic variant does this represent according to the Lanz classification?
. Group I
. Group II
. Group III
. Group IV
. Group V

Correct Answer & Explanation

. Group III

Explanation

The Lanz classification describes variations of the median nerve at the wrist. Group III represents an extraligamentous thenar motor branch taking off from the ulnar side of the median nerve.

Question 4420

Topic: 7. Hand and Wrist

A 22-year-old male sustains a displaced fracture of the proximal pole of the scaphoid. The high risk of avascular necrosis in this specific injury is primarily due to the retrograde blood supply from which specific vessel?

. Palmar carpal branch of the radial artery
. Dorsal carpal branch of the radial artery
. Superficial palmar arch
. Deep palmar arch
. Ulnar artery

Correct Answer & Explanation

. Palmar carpal branch of the radial artery

Explanation

The scaphoid receives 70-80% of its primary blood supply from the dorsal carpal branch of the radial artery. These vessels enter distally and provide retrograde flow to the proximal pole, making it highly susceptible to avascular necrosis after fracture.

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