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7. Hand and Wrist MCQs

Practice Set 256 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 5101

Topic: Wrist & Carpus

A patient undergoes a Bier block using intravenous lidocaine for a distal radius fracture reduction. She suddenly develops tinnitus, perioral numbness, and a metallic taste. What is the most appropriate initial medical antidote for this severe toxicity?

. Intravenous flumazenil
. Intravenous naloxone
. Intravenous 20% lipid emulsion
. Intravenous calcium gluconate
. Immediate hemodialysis

Correct Answer & Explanation

. Intravenous 20% lipid emulsion

Explanation

The patient is exhibiting signs of Local Anesthetic Systemic Toxicity (LAST). The primary specific treatment includes airway management and prompt administration of 20% intravenous lipid emulsion to sequester the lipophilic anesthetic molecules.

Question 5102

Topic: 7. Hand and Wrist

A 25-year-old male sustains a zone 2 injury to Guyon's canal. Which of the following clinical deficits is most likely to be observed?

. Combined motor and sensory deficits of the ulnar nerve
. Isolated motor deficit of the ulnar-innervated intrinsic hand muscles
. Isolated sensory deficit to the volar little finger
. Loss of sensation to the dorsal ulnar hand
. Weakness of the flexor carpi ulnaris

Correct Answer & Explanation

. Isolated motor deficit of the ulnar-innervated intrinsic hand muscles

Explanation

Guyon's canal is divided into three zones. Zone 2 involves the deep motor branch of the ulnar nerve, so an injury here causes an isolated motor deficit of the intrinsic hand muscles without sensory loss.

Question 5103

Topic: 7. Hand and Wrist

What is the primary function of the A2 and A4 pulleys in the flexor tendon system of the hand?

. To provide nutritional support via synovial diffusion
. To prevent bowstringing of the flexor tendons
. To facilitate smooth gliding by secreting hyaluronic acid
. To act as an insertion point for the lumbricals
. To limit hyperextension of the DIP joint

Correct Answer & Explanation

. To prevent bowstringing of the flexor tendons

Explanation

The annular pulleys, specifically the critical A2 (proximal phalanx) and A4 (middle phalanx) pulleys, act as biomechanical fulcrums to keep the flexor tendons closely apposed to the bone. This prevents bowstringing and preserves mechanical efficiency.

Question 5104

Topic: 7. Hand and Wrist
Following primary repair of a completely lacerated flexor tendon in Zone II of the hand, the tendon undergoes three phases of healing: inflammatory, fibroblastic, and remodeling. During the remodeling (maturation) phase, what is the defining change occurring within the collagen matrix?
. Replacement of robust Type I collagen with provisional Type III collagen
. A massive influx of inflammatory macrophages and angiogenesis
. Random and disorganized deposition of ground substance
. Cross-linking and strict longitudinal realignment of Type I collagen fibers
. Transformation of local tenocytes into hypertrophic chondrocytes

Correct Answer & Explanation

. Cross-linking and strict longitudinal realignment of Type I collagen fibers

Explanation

During the remodeling phase (which begins around 3-4 weeks and lasts for months), the cellularity and synthetic activity decrease. The weaker, disorganized Type III collagen laid down during the fibroblastic phase is gradually replaced by stronger Type I collagen. These Type I fibers undergo robust intermolecular cross-linking and realign longitudinally in response to applied mechanical stress, maximizing the tendon's tensile strength.

Question 5105

Topic: 7. Hand and Wrist

A 34-year-old male sustained a midshaft humerus fracture resulting in an irreversible radial nerve palsy. Tendon transfers are planned to restore function. Which of the following is the most appropriate donor to restore active wrist extension?

. Flexor carpi ulnaris (FCU)
. Flexor digitorum superficialis (FDS) of the middle finger
. Pronator teres (PT)
. Palmaris longus (PL)
. Flexor carpi radialis (FCR)

Correct Answer & Explanation

. Pronator teres (PT)

Explanation

In the standard transfer for radial nerve palsy to restore wrist extension, the Pronator Teres (PT) is transferred to the Extensor Carpi Radialis Brevis (ECRB). ECRB is chosen over ECRL because its insertion at the base of the 3rd metacarpal produces central wrist extension, whereas ECRL produces radial deviation.

Question 5106

Topic: 7. Hand and Wrist

In flexor tendon injuries of the hand, Zone II is historically referred to as 'no man's land'. What are the proximal and distal anatomic boundaries of Zone II?

. Carpal tunnel to the A1 pulley
. A1 pulley to the insertion of the flexor digitorum superficialis (FDS)
. Insertion of FDS to the insertion of flexor digitorum profundus (FDP)
. Musculotendinous junction to the carpal tunnel
. Distal palmar crease to the distal interphalangeal (DIP) joint

Correct Answer & Explanation

. A1 pulley to the insertion of the flexor digitorum superficialis (FDS)

Explanation

Flexor tendon Zone II begins proximally at the proximal edge of the A1 pulley (approximately at the distal palmar crease) and ends distally at the insertion of the flexor digitorum superficialis (FDS) tendon in the middle phalanx. It is called 'no man's land' due to the tight fibro-osseous sheath housing both FDP and FDS, making surgical outcomes challenging.

Question 5107

Topic: 7. Hand and Wrist
A 25-year-old sustains a volar laceration over the proximal phalanx of the index finger, completely transecting both the FDS and FDP tendons. 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 called 'no man's land', extends from the proximal edge of the A1 pulley to the insertion of the flexor digitorum superficialis (FDS) tendon. Both FDS and FDP are frequently injured together here.

Question 5108

Topic: 7. Hand and Wrist
A 30-year-old manual laborer presents with chronic dorsal wrist pain. Radiographs reveal advanced sclerosis of the lunate (Kienböck's disease) and an ulnar minus variance. Which joint-leveling procedure is best indicated?
. Proximal row carpectomy
. Total wrist arthrodesis
. Radial shortening osteotomy
. Ulnar shortening osteotomy
. Lunate excision alone

Correct Answer & Explanation

. Radial shortening osteotomy

Explanation

In early to mid-stage Kienböck's disease with negative ulnar variance, a radial shortening osteotomy levels the radiocarpal joint, thereby decreasing the mechanical load transmitted through the avascular lunate.

Question 5109

Topic: Nerve & Tendon
A heavy machinery worker sustains a deep volar laceration in "No Man's Land" of the hand, resulting in an inability to flex the proximal and distal interphalangeal joints. Which flexor tendon zone is anatomically involved?
. 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 to the insertion of the flexor digitorum superficialis (FDS). It is historically termed "No Man's Land" due to the tight fibro-osseous tunnel that makes surgical repair prone to adhesions and poor functional outcomes.

Question 5110

Topic: 7. Hand and Wrist

Following a laceration in Zone II of the flexor tendons of the hand, a surgeon performs a primary repair. Biomechanically, which core suture parameter contributes most to the tensile strength of the repair?

. The type of knot tied
. The location of the knot (inside vs. outside the repair site)
. The number of core suture strands crossing the repair site
. The use of an epitendinous running suture
. The caliber of the suture material used

Correct Answer & Explanation

. The number of core suture strands crossing the repair site

Explanation

Increasing the number of core suture strands directly increases the tensile strength of a flexor tendon repair. A 4-strand or 6-strand repair provides significantly greater strength than a 2-strand technique, safely permitting early active mobilization.

Question 5111

Topic: 7. Hand and Wrist

A 45-year-old carpenter presents with volar forearm pain and numbness in the radial three and a half digits. Unlike typical carpal tunnel syndrome, the patient also notes decreased sensation over the thenar eminence. Which of the following is the most likely site of nerve compression?

. Ligament of Struthers
. Arcade of Frohse
. Between the two heads of the pronator teres
. Carpal tunnel
. Guyon's canal

Correct Answer & Explanation

. Between the two heads of the pronator teres

Explanation

The sensory deficit over the thenar eminence indicates involvement of the palmar cutaneous branch of the median nerve, which branches proximal to the carpal tunnel. This points to proximal median nerve compression, most commonly between the heads of the pronator teres in Pronator Syndrome.

Question 5112

Topic: Nerve & Tendon

A 30-year-old male presents with inability to actively flex the distal interphalangeal joint of his ring finger after a rugby tackle. Radiographs and ultrasound show the flexor digitorum profundus (FDP) tendon retracted into the palm. According to the Leddy-Packer classification, what is the ideal timeframe for surgical repair of this specific injury pattern?

. Within 24 hours
. Within 7 to 10 days
. Within 3 to 4 weeks
. After 6 weeks using a tendon graft
. Conservative management is preferred

Correct Answer & Explanation

. Within 7 to 10 days

Explanation

A Type I FDP avulsion (Jersey finger) involves tendon retraction into the palm, disrupting its vincula and blood supply. It must be surgically repaired within 7 to 10 days to prevent permanent ischemic contracture of the tendon.

Question 5113

Topic: Wrist & Carpus

An orthopedic study compares a new plate design to a standard plate for distal radius fractures. The study concludes there is no significant difference in union rates, but the actual true difference was missed due to an insufficient sample size. This is an example of which of the following statistical errors?

. Type I error
. Type II error
. Selection bias
. Recall bias
. Confounding

Correct Answer & Explanation

. Type II error

Explanation

A Type II error (beta error) occurs when a study fails to reject the null hypothesis when it is actually false (a false negative). This is most commonly due to low statistical power resulting from an inadequate sample size. A Type I error (alpha error) is a false positive.

Question 5114

Topic: 7. Hand and Wrist
A 28-year-old carpenter suffers a laceration to his volar index finger at the level of the proximal phalanx, transecting both the FDP and FDS tendons. This injury corresponds to which flexor tendon zone, historically known as 'no man's land'?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II extends from the proximal aspect of the A1 pulley to the insertion of the Flexor Digitorum Superficialis (FDS) on the middle phalanx. It contains both the FDP and FDS within a tight fibro-osseous sheath. It was historically called 'no man's land' by Bunnell because of the poor outcomes and high rates of restrictive adhesion following primary repair.

Question 5115

Topic: 7. Hand and Wrist

Which of the following conditions is generally considered an absolute contraindication for an endoscopic carpal tunnel release?

. Bilateral carpal tunnel syndrome
. Previous failed open carpal tunnel release
. Presence of a space-occupying lesion in the carpal tunnel
. Diabetes mellitus
. End-stage renal disease

Correct Answer & Explanation

. Presence of a space-occupying lesion in the carpal tunnel

Explanation

The presence of a known or suspected space-occupying lesion (such as a ganglion cyst, tumor, or severe tenosynovitis requiring synovectomy) is an absolute contraindication to endoscopic carpal tunnel release, as it requires direct visualization and open excision or biopsy. Previous failed open release is a relative contraindication.

Question 5116

Topic: 7. Hand and Wrist

A 24-year-old patient presents with long-standing wrist pain. Radiographs demonstrate a scaphoid nonunion with advanced carpal collapse (SNAC wrist). According to the typical predictable progression of SNAC arthritis, which articulation is classically spared and remains preserved even in late stages?

. Radioscaphoid joint
. Scaphocapitate joint
. Capitolunate joint
. Radiolunate joint
. Trapeziometacarpal joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In the progression of Scaphoid Nonunion Advanced Collapse (SNAC), the radiolunate articulation is classically spared. This is due to the concentric, spherical congruency of the lunate fossa and lunate, which avoids abnormal contact stresses.

Question 5117

Topic: 7. Hand and Wrist

A 45-year-old female presents with severe neck pain radiating to her lateral right forearm and the thumb and index finger. Physical examination reveals weakness in wrist extension and a diminished brachioradialis reflex. Which cervical nerve root is most likely compressed?

. C4
. C5
. C6
. C7
. C8

Correct Answer & Explanation

. C6

Explanation

Compression of the C6 nerve root classically presents with weakness in wrist extension, a diminished brachioradialis reflex, and paresthesias in the thumb and index finger. This is most commonly due to a C5-C6 herniated nucleus pulposus.

Question 5118

Topic: 7. Hand and Wrist
A 28-year-old laborer sustains a deep laceration over the volar aspect of the proximal phalanx, completely severing the flexor digitorum profundus and superficialis tendons. This injury corresponds to which flexor tendon zone, classically known as "no man's land"?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II extends from the A1 pulley to the insertion of the FDS on the middle phalanx. It is called "no man's land" due to historically poor surgical outcomes from adhesions between the FDP and FDS tendons within the flexor sheath.

Question 5119

Topic: 7. Hand and Wrist

A 24-year-old male falls on an outstretched hand and sustains a fracture through the proximal pole of the scaphoid. Why is this specific fracture pattern at an exceptionally high risk for avascular necrosis?

. The scaphoid relies entirely on the volar carpal branch of the radial artery
. Blood supply enters distally and flows in a retrograde fashion
. The proximal pole has no cartilaginous covering
. It frequently involves the scapholunate ligament
. High concentrations of synovial fluid inhibit healing

Correct Answer & Explanation

. Blood supply enters distally and flows in a retrograde fashion

Explanation

The major blood supply to the scaphoid enters the dorsal ridge distally and flows in a retrograde fashion to the proximal pole. Fractures at the proximal pole completely disrupt this intraosseous supply, leading to high rates of avascular necrosis.

Question 5120

Topic: 7. Hand and Wrist

During a volar approach to the wrist, the palmar cutaneous branch of the median nerve is most at risk of injury if the incision is placed in which location relative to the flexor carpi radialis (FCR) tendon?

. Directly over the FCR tendon
. Ulnar to the FCR tendon
. Radial to the FCR tendon
. Between the FCR and the radial artery
. Proximal to the distal wrist crease along the brachioradialis

Correct Answer & Explanation

. Ulnar to the FCR tendon

Explanation

The palmar cutaneous branch of the median nerve runs longitudinally between the palmaris longus and the FCR tendons. This makes it highly vulnerable to surgical incisions placed ulnar to the FCR tendon.

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