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7. Hand and Wrist MCQs

Practice Set 98 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 1941

Topic: 7. Hand and Wrist
A rugby player sustains a closed injury to his right ring finger while grabbing an opponent's jersey. He is unable to actively flex the DIP joint. Imaging shows an avulsion fracture of the distal phalanx base retracted to the level of the PIP joint. According to the Leddy and Packer classification, what type of injury is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

Leddy and Packer classification of FDP avulsion (Jersey finger): Type I - retracted to palm; Type II - retracted to the PIP joint level (held by the vinculum longum); Type III - large bony fragment avulsed and caught at the A4 pulley; Type IV - osseous fragment with concurrent tendon avulsion from the fragment.

Question 1942

Topic: 7. Hand and Wrist

A 42-year-old pregnant female presents with numbness and tingling in her right thumb, index, and long fingers. EMG/NCS is obtained.

Which of the following is the earliest and most sensitive nerve conduction study finding in carpal tunnel syndrome?

. Increased distal motor latency
. Decreased motor nerve conduction velocity
. Increased distal sensory latency
. Fibrillation potentials in the abductor pollicis brevis
. Decreased sensory nerve action potential amplitude

Correct Answer & Explanation

. Increased distal sensory latency

Explanation

In carpal tunnel syndrome (median nerve compression), the sensory fibers are typically affected before the motor fibers. Therefore, a delay in the sensory nerve conduction (increased distal sensory latency) is generally the earliest and most sensitive electrodiagnostic finding.

Question 1943

Topic: Wrist & Carpus
A 45-year-old manual laborer presents with chronic right wrist pain. He recalls a severe sprain 10 years ago that was untreated. Radiographs demonstrate an established scaphoid nonunion with arthritic changes at the radioscaphoid and capitolunate joints, but preservation of the radiolunate articulation. Based on the expected stage of this disease process, which of the following is the most appropriate surgical treatment?
. Open reduction internal fixation of the scaphoid with vascularized bone graft
. Radial styloidectomy alone
. Proximal row carpectomy (PRC)
. Total wrist arthroplasty
. Scaphotrapeziotrapezoid (STT) fusion

Correct Answer & Explanation

. Proximal row carpectomy (PRC)

Explanation

This patient has Scaphoid Nonunion Advanced Collapse (SNAC) Stage III, defined by arthritis at both the radioscaphoid joint and the midcarpal (capitolunate) joint, with a preserved radiolunate joint. Open reduction and internal fixation is no longer indicated once degenerative changes have occurred. Radial styloidectomy is insufficient for Stage III. The standard salvage procedures for SNAC Stage III (and SLAC Stage III) are either a proximal row carpectomy (PRC) or a scaphoid excision with a four-corner fusion. The radiolunate fossa is typically spared in both SLAC and SNAC wrists because the lunate maintains a concentric articulation with the radius.

Question 1944

Topic: 7. Hand and Wrist

In the anatomy of the flexor tendon sheath of the digits, preservation of certain structures is critical to prevent bowstringing of the flexor tendons. During an extensive tenolysis procedure of the index finger, which two annular pulleys are the most critical to preserve?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The flexor tendon sheath contains a series of thickened bands known as annular (A) and cruciate (C) pulleys. The A2 and A4 pulleys are the major mechanical pulleys that hold the flexor tendons close to the phalanges, preventing bowstringing during active flexion. The A2 pulley is located over the proximal phalanx, and the A4 pulley is over the middle phalanx. They are biomechanically the most critical.

Question 1945

Topic: 7. Hand and Wrist



A 60-year-old female underwent volar locked plating of a comminuted distal radius fracture 4 months ago. She now presents complaining of the sudden inability to bend the tip of her thumb. She reports hearing a 'pop' in her wrist yesterday while opening a jar. Which of the following technical errors during the initial surgery is the most likely cause of her current presentation?

. Use of screws that were too long penetrating the dorsal cortex
. Failure to repair the pronator quadratus during closure
. Placement of the volar plate anterior to the watershed line
. Over-distraction of the fracture resulting in median nerve ischemia
. Inadequate reduction of the dorsal tilt

Correct Answer & Explanation

. Placement of the volar plate anterior to the watershed line

Explanation

The sudden inability to flex the interphalangeal joint of the thumb months after a volar distal radius plate placement is classic for an iatrogenic rupture of the Flexor Pollicis Longus (FPL) tendon. This occurs due to mechanical attrition of the tendon against the hardware. The most critical risk factor for FPL rupture is placing the volar plate too far distally, specifically anterior to the 'watershed line' (a transverse ridge on the volar margin of the distal radius), which allows the plate to prominently impinge on the flexor tendons.

Question 1946

Topic: Wrist & Carpus

A 72-year-old female sustains a distal radius fracture.

She undergoes volar locking plate fixation. Three months postoperatively, she suddenly cannot flex the interphalangeal joint of her thumb. Which tendon is most likely injured?

. Flexor carpi radialis
. Extensor pollicis longus
. Flexor pollicis longus
. Flexor digitorum profundus to the index finger
. Abductor pollicis longus

Correct Answer & Explanation

. Flexor pollicis longus

Explanation

Attrition rupture of the Flexor Pollicis Longus (FPL) tendon is a known complication of volar plating of the distal radius. It typically occurs due to plate prominence distal to the watershed line, which leads to friction against the FPL tendon during thumb motion.

Question 1947

Topic: 7. Hand and Wrist
A 45-year-old male presents with chronic radial-sided wrist pain. He reports a history of a 'sprained wrist' 10 years ago that was never treated. A radiograph is obtained. It shows a scaphoid nonunion with radioscaphoid arthritis localized to the radial styloid. The midcarpal joint and capitolunate articulation are preserved. Which of the following is the most appropriate surgical treatment?
. Proximal row carpectomy (PRC)
. Four-corner arthrodesis
. Total wrist arthrodesis
. Radial styloidectomy with scaphoid nonunion takedown and bone grafting
. Scaphoid excision and intercarpal ligament reconstruction

Correct Answer & Explanation

. Radial styloidectomy with scaphoid nonunion takedown and bone grafting

Explanation

This describes Scaphoid Nonunion Advanced Collapse (SNAC) Stage I, characterized by arthritis limited to the articulation between the distal pole of the scaphoid and the radial styloid. The recommended treatment for SNAC Stage I is radial styloidectomy combined with scaphoid fixation and bone grafting. PRC or four-corner fusion would be indicated for more advanced stages (Stage II or III) where the midcarpal or radiocarpal joint (beyond the styloid) is involved.

Question 1948

Topic: 7. Hand and Wrist

A 28-year-old female sustains a volar laceration to her left index finger over the proximal phalanx, resulting in severing of both the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) tendons in Zone II. During surgical repair, preserving or reconstructing the flexor pulley system is essential. Which two pulleys are considered mechanically critical to prevent bowstringing of the flexor tendons?

. A1 and A3
. A2 and A4
. A1 and C1
. A3 and A5
. C2 and C3

Correct Answer & Explanation

. A2 and A4

Explanation

The flexor tendon pulley system of the fingers consists of five annular (A) and three cruciate (C) pulleys. The A2 and A4 pulleys are the major biomechanical workhorses that keep the flexor tendons closely apposed to the phalanges during flexion. Loss or incompetence of the A2 and A4 pulleys leads to bowstringing, significantly reducing the mechanical advantage and excursion of the tendons, leading to a profound loss of active digital flexion.

Question 1949

Topic: Wrist & Carpus

A 60-year-old female presents with sudden inability to actively flex the interphalangeal (IP) joint of her thumb. She underwent open reduction and internal fixation of a distal radius fracture with a volar locking plate 8 months ago. Radiographs show the plate is well-fixed but positioned distally on the radius. What anatomical landmark was most likely violated, leading to this specific complication?

. The sigmoid notch
. Lister's tubercle
. The watershed line
. The pronator quadratus insertion
. The radial styloid groove

Correct Answer & Explanation

. The watershed line

Explanation

This patient has suffered a rupture of the Flexor Pollicis Longus (FPL) tendon, which is the most common tendon rupture following volar plate fixation of the distal radius. The primary risk factor is placing the plate distal to the 'watershed line' (the bony ridge at the distal margin of the pronator fossa). When the plate sits anterior to this line, it acts as a prominent friction point against the flexor tendons, particularly the FPL, leading to attritional wear and delayed rupture.

Question 1950

Topic: 7. Hand and Wrist
A 45-year-old male laborer presents with chronic right wrist pain. Radiographs reveal a scapholunate advance collapse (SLAC) pattern. Which joint is classically spared in the progression of SLAC wrist arthritis?
. Radioscaphoid joint
. Radiolunate joint
. Capitolunate joint
. Scapho-trapezio-trapezoidal (STT) joint
. Scaphocapitate joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In the typical progression of a SLAC wrist, the radiolunate joint is characteristically spared due to the congruent, spherical nature of the articulation, which distributes contact stresses evenly despite carpal collapse. The progression of arthritis in SLAC wrist follows a predictable pattern: Stage I involves the radial styloid-scaphoid articulation; Stage II involves the entire radioscaphoid fossa; Stage III involves the capitolunate joint.

Question 1951

Topic: 7. Hand and Wrist

In evaluating a patient with suspected carpal tunnel syndrome, which of the following clinical tests is considered the most sensitive for detecting early sensory nerve dysfunction?

. Tinel's sign
. Phalen's maneuver
. Semmes-Weinstein monofilament testing
. Two-point discrimination test
. Durkan's carpal compression test

Correct Answer & Explanation

. Semmes-Weinstein monofilament testing

Explanation

Semmes-Weinstein monofilament testing is considered the most sensitive objective clinical test for detecting early sensory nerve dysfunction in carpal tunnel syndrome. It tests threshold sensibility, which is lost earlier than innervation density (tested by two-point discrimination). Durkan's test is the most sensitive provocative maneuver, but for measuring nerve function directly, monofilament testing is superior.

Question 1952

Topic: 7. Hand and Wrist

A 22-year-old male sustains a proximal pole scaphoid fracture. Which of the following best describes the predominant arterial supply to the scaphoid that makes this specific fracture pattern highly prone to avascular necrosis (AVN) and nonunion?

. Volar carpal branch of the radial artery entering distally
. Dorsal carpal branch of the radial artery entering distally and flowing retrograde
. Volar carpal branch of the ulnar artery entering proximally
. Dorsal carpal branch of the ulnar artery entering distally
. Interosseous artery branches entering directly into the proximal pole

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery entering distally and flowing retrograde

Explanation

The scaphoid is primarily supplied by the dorsal carpal branch of the radial artery (supplying 70-80% of the bone, including the proximal pole). These vessels enter the scaphoid distally at the dorsal ridge and flow in a retrograde fashion toward the proximal pole. Because of this retrograde blood supply, fractures at the proximal pole disrupt the vascularity to the proximal fragment, leading to high rates of AVN and nonunion.

Question 1953

Topic: 7. Hand and Wrist

A 45-year-old woman presents with severe carpal tunnel syndrome. During open carpal tunnel release, the surgeon must be careful to avoid injuring the recurrent motor branch of the median nerve. This branch most commonly exhibits which of the following anatomic variations?

. Extraligamentous with recurrent course
. Subligamentous with recurrent course
. Transligamentous
. Ulnar to the median nerve main trunk
. Piercing the transverse carpal ligament at the ulnar border

Correct Answer & Explanation

. Extraligamentous with recurrent course

Explanation

According to Lanz's classification, the most common anatomic course of the recurrent motor branch of the median nerve is extraligamentous with a recurrent course (approximately 50-80% of cases), branching distal to the transverse carpal ligament and turning back to innervate the thenar musculature.

Question 1954

Topic: 7. Hand and Wrist
A 28-year-old rugby player presents with an inability to actively flex the distal interphalangeal (DIP) joint of his ring finger after catching it in an opponent's jersey. Radiographs reveal a small bony avulsion fragment located volar to the proximal interphalangeal (PIP) joint. According to the Leddy and Packer classification, what is the correct injury type and the anatomic structure that arrests the retracted tendon?
. Type I, retracts to the palm and is held by the lumbrical origin
. Type II, retracts to the PIP joint and is held by the vinculum longum
. Type III, retracts to the A2 pulley
. Type III, retracts to the A4 pulley and involves a large bony avulsion
. Type IV, involves an avulsion from the distal phalanx base with an associated central slip injury

Correct Answer & Explanation

. Type II, retracts to the PIP joint and is held by the vinculum longum

Explanation

Jersey finger injuries are classified by Leddy and Packer. Type I involves retraction of the FDP tendon into the palm, often requiring repair within 7-10 days due to compromised blood supply. Type II involves retraction to the level of the PIP joint, where it is caught by the intact vinculum longum (or Camper's chiasm) and often has a small bony fragment visible on X-ray at the PIP level. Type III involves a large bony avulsion that gets caught at the A4 pulley.

Question 1955

Topic: 7. Hand and Wrist

A 45-year-old woman undergoes an open carpal tunnel release. Postoperatively, she reports a new, severe weakness in thumb opposition, despite normal opposition preoperatively. The surgeon suspects an iatrogenic nerve injury. The affected nerve branch most likely originates from which aspect of the median nerve?

. Ulnar side of the median nerve, proximal to the transverse carpal ligament
. Radial side of the median nerve, frequently just distal to the transverse carpal ligament
. Ulnar side of the median nerve, within Guyon's canal
. Posterior interosseous nerve branch
. Anterior interosseous nerve branch

Correct Answer & Explanation

. Radial side of the median nerve, frequently just distal to the transverse carpal ligament

Explanation

The recurrent motor branch of the median nerve innervates the thenar muscles (opponens pollicis, abductor pollicis brevis, superficial head of flexor pollicis brevis). In the most common anatomic variation (extraneous), it branches from the radial side of the median nerve just distal to the transverse carpal ligament and courses recurrently. Injury to this branch during carpal tunnel release results in loss of thumb opposition.

Question 1956

Topic: Nerve & Tendon

A 28-year-old carpenter sustains a laceration to the volar aspect of his index finger, resulting in an inability to flex the distal interphalangeal (DIP) joint.

During zone II flexor tendon repair, the surgeon must be mindful of the tendon's blood supply. The segmental vascular supply to the flexor tendons within the digital sheath is provided primarily by:

. Small branches from the palmar digital arteries entering through the vincula
. Direct branches from the superficial palmar arch
. Diffusion from the surrounding synovial fluid exclusively
. Longitudinal vessels arising directly from the muscle belly
. Branches from the common digital arteries piercing the A2 pulley

Correct Answer & Explanation

. Small branches from the palmar digital arteries entering through the vincula

Explanation

Flexor tendons in Zone II receive nutrition via a dual mechanism: vascular perfusion and synovial diffusion. The vascular supply is provided segmentally by small branches of the digital arteries that enter the dorsal aspect of the tendons through the vincula (vincula brevia and longa).

Question 1957

Topic: 7. Hand and Wrist
A 45-year-old construction worker presents with chronic wrist pain and weakness. Radiographs reveal a scaphoid nonunion advanced collapse (SNAC) pattern. The imaging demonstrates arthritic changes involving the entire radioscaphoid joint as well as the capitolunate joint, while the radiolunate joint is completely spared. This pattern corresponds to which stage of a SNAC wrist?
. Stage I
. Stage II
. Stage III
. Stage IV
. Stage V

Correct Answer & Explanation

. Stage III

Explanation

SNAC wrist staging is based on the progression of arthritis. Stage I: arthrosis at the radial styloid. Stage II: arthrosis involving the entire radioscaphoid articulation. Stage III: arthrosis advances to involve the capitolunate joint. The radiolunate joint is typically spared until end-stage (Stage IV involves the entire carpus).

Question 1958

Topic: 7. Hand and Wrist

A 42-year-old female presents with an acute finger injury after her hand was struck by a basketball.

Radiographs reveal a dorsal avulsion fracture of the distal phalanx involving 45% of the articular surface, accompanied by volar subluxation of the distal phalanx (bony mallet finger). What is the most appropriate management for this specific injury pattern?

. Aluminum splinting of the DIP joint in slight hyperextension for 6-8 weeks
. Closed reduction and percutaneous pinning (e.g., extension block pinning)
. Immediate DIP joint arthrodesis
. Excision of the fracture fragment and primary tendon advancement
. Buddy taping to the adjacent middle finger for 4 weeks

Correct Answer & Explanation

. Closed reduction and percutaneous pinning (e.g., extension block pinning)

Explanation

While conservative splinting is appropriate for soft tissue mallet fingers and small avulsion fractures, surgical intervention is indicated for bony mallet fingers when the fracture fragment involves >30-50% of the articular surface or when there is volar subluxation of the distal phalanx. Closed reduction and percutaneous extension block pinning is the standard surgical treatment.

Question 1959

Topic: Nerve & Tendon

A 5-year-old boy presents to the emergency department after falling from monkey bars. He sustained a displaced extension-type supracondylar humerus fracture. Examination reveals an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which of the following nerves is most likely injured?

. Anterior interosseous nerve
. Posterior interosseous nerve
. Ulnar nerve
. Radial nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is a branch of the median nerve and is the most commonly injured nerve in extension-type supracondylar humerus fractures. Injury to the AIN results in the inability to form an 'OK' sign due to weakness of the flexor pollicis longus and the flexor digitorum profundus to the index finger.

Question 1960

Topic: Hand Trauma & Infection

A 35-year-old mechanic presents with a swollen, painful index finger 3 days after sustaining a puncture wound. The finger is held in a flexed posture, is uniformly swollen, tender along the volar aspect, and exquisitely painful with passive extension. What is the most appropriate next step in management?

. Oral antibiotics and buddy taping
. Immediate bedside incision and drainage in the emergency department
. Surgical irrigation and debridement of the flexor tendon sheath and intravenous antibiotics
. Corticosteroid injection into the flexor sheath
. Splinting in extension and close observation

Correct Answer & Explanation

. Surgical irrigation and debridement of the flexor tendon sheath and intravenous antibiotics

Explanation

The patient presents with all four Kanavel signs (fusiform swelling, flexed posture, tenderness along the flexor tendon sheath, and pain on passive extension), indicating pyogenic flexor tenosynovitis. This is a surgical emergency requiring prompt formal surgical irrigation and debridement of the flexor tendon sheath in the operating room, along with broad-spectrum intravenous antibiotics.

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