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7. Hand and Wrist MCQs

Practice Set 58 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 1141

Topic: 7. Hand and Wrist

When comparing endoscopic carpal tunnel release to open carpal tunnel release, the endoscopic technique is generally associated with a higher risk of:

. Prolonged scar tenderness
. Pillar pain
. Iatrogenic nerve injury
. Postoperative infection
. Delayed return to work

Correct Answer & Explanation

. Iatrogenic nerve injury

Explanation

Endoscopic carpal tunnel release has a higher reported rate of transient nerve neuropraxia and structural iatrogenic nerve injury compared to open release. However, it is associated with a faster initial return to work and less early scar tenderness.

Question 1142

Topic: 7. Hand and Wrist

A 55-year-old woman presents with nocturnal paresthesias in her thumb, index, and middle fingers. Phalen's test is positive. When obtaining electrodiagnostic studies, which of the following is typically the earliest and most sensitive abnormality observed in carpal tunnel syndrome?

. Increased insertional activity in the abductor pollicis brevis
. Prolonged distal motor latency
. Prolonged distal sensory latency
. Fibrillation potentials in the thenar musculature
. Decreased motor nerve conduction velocity in the forearm

Correct Answer & Explanation

. Prolonged distal sensory latency

Explanation

Sensory fibers are more susceptible to early compression in carpal tunnel syndrome than motor fibers. Therefore, a prolonged distal sensory latency is the earliest and most sensitive electrodiagnostic finding.

Question 1143

Topic: Nerve & Tendon

During surgical release of a pediatric trigger thumb, which neurological structure is at highest risk of iatrogenic injury due to its anatomical course?

. Ulnar digital nerve of the thumb
. Radial digital nerve of the thumb
. Palmar cutaneous branch of the median nerve
. Recurrent motor branch of the median nerve
. Superficial sensory branch of the radial nerve

Correct Answer & Explanation

. Radial digital nerve of the thumb

Explanation

The radial digital nerve of the thumb is at high risk during trigger thumb release because it crosses obliquely from ulnar to radial over the flexor sheath near the metacarpophalangeal flexion crease. Meticulous blunt dissection and lateral retraction are required to protect it.

Question 1144

Topic: 7. Hand and Wrist

To avoid injury to the palmar cutaneous branch of the median nerve (PCBMN) during open carpal tunnel release, the incision is typically placed ulnar to the thenar crease. Proximally at the wrist level, the PCBMN normally travels between which two structures?

. Flexor carpi ulnaris and flexor digitorum superficialis
. Flexor carpi radialis and palmaris longus
. Palmaris longus and flexor digitorum superficialis
. Flexor pollicis longus and flexor carpi radialis
. Brachioradialis and flexor carpi radialis

Correct Answer & Explanation

. Flexor carpi radialis and palmaris longus

Explanation

The PCBMN branches from the radial aspect of the median nerve proximal to the wrist crease and travels distally between the flexor carpi radialis (FCR) and palmaris longus (PL) tendons. Injury to this nerve results in painful neuromas and numbness over the base of the thenar eminence.

Question 1145

Topic: Nerve & Tendon

A 58-year-old patient with long-standing type 1 diabetes mellitus presents with a locking ring finger. What is the most accurate information regarding the expected outcome of a single corticosteroid injection for her trigger finger compared to a non-diabetic patient?

. They have an equivalent success rate but higher risk of spontaneous tendon rupture.
. They are strictly contraindicated due to the risk of precipitating a hyperglycemic crisis.
. They have a significantly lower long-term success rate, approximately 50%.
. They require an ultrasound-guided intra-tendinous injection to achieve similar outcomes.
. They carry a 50% risk of causing profound deep space infections.

Correct Answer & Explanation

. They have a significantly lower long-term success rate, approximately 50%.

Explanation

Corticosteroid injections for trigger digits in diabetic patients have a much lower long-term resolution rate (approximately 50%) compared to the 80-90% success rate seen in non-diabetic patients. Diabetics frequently require subsequent surgical release of the A1 pulley.

Question 1146

Topic: 7. Hand and Wrist

During an open carpal tunnel release, the transverse carpal ligament is completely divided to decompress the median nerve. Which of the following bony structures form the ulnar attachments of this ligament?

. Scaphoid tuberosity and ridge of the trapezium
. Pisiform and hook of the hamate
. Lunate and triquetrum
. Capitate and base of the third metacarpal
. Styloid process of the ulna and pisiform

Correct Answer & Explanation

. Pisiform and hook of the hamate

Explanation

The transverse carpal ligament forms the roof of the carpal tunnel. It attaches ulnarly to the pisiform and the hook of the hamate, and radially to the scaphoid tuberosity and the ridge of the trapezium.

Question 1147

Topic: 7. Hand and Wrist

A 30-year-old mechanic sustains a severe avulsion injury to the dorsum of his hand. Meticulous debridement leaves a 4x4 cm defect with exposed metacarpal bone stripped of its periosteum and extensor tendons completely devoid of paratenon. What is the most appropriate definitive soft tissue coverage for this defect?

. Split-thickness skin graft (STSG)
. Full-thickness skin graft (FTSG)
. Healing by secondary intention
. Local or distant flap coverage
. Application of an allograft dermal matrix followed by immediate STSG

Correct Answer & Explanation

. Local or distant flap coverage

Explanation

Skin grafts require a highly vascularized bed to survive and will reliably fail if placed directly over bare bone (without periosteum), bare tendon (without paratenon), or bare cartilage. Therefore, a vascularized flap (local, regional, or free) is strictly required for coverage.

Question 1148

Topic: Nerve & Tendon

Percutaneous release of the A1 pulley is an accepted treatment for trigger finger. For which of the following digits is percutaneous release considered relatively contraindicated due to the anatomical vulnerability of the adjacent digital nerve?

. Thumb
. Index finger
. Middle finger
. Ring finger
. Small finger

Correct Answer & Explanation

. Index finger

Explanation

Percutaneous release of the index finger is generally contraindicated because its radial digital nerve crosses obliquely over the proximal aspect of the A1 pulley. This positioning makes the nerve highly susceptible to iatrogenic transection during a blind percutaneous approach.

Question 1149

Topic: 7. Hand and Wrist

A 70-year-old woman presents with severe, end-stage carpal tunnel syndrome, demonstrating profound thenar atrophy and an inability to palmar abduct the thumb. Which of the following thumb intrinsic muscles is most likely to retain its normal function and innervation?

. Abductor pollicis brevis
. Opponens pollicis
. Superficial head of the flexor pollicis brevis
. Adductor pollicis
. First lumbrical

Correct Answer & Explanation

. Adductor pollicis

Explanation

The adductor pollicis is innervated by the deep branch of the ulnar nerve and remains functional in isolated severe carpal tunnel syndrome. The abductor pollicis brevis, opponens pollicis, and superficial head of the flexor pollicis brevis are median nerve innervated.

Question 1150

Topic: Wrist & Carpus

A 55-year-old female presents with an inability to flex her thumb interphalangeal joint 6 months after open reduction and internal fixation of a distal radius fracture with a volar locking plate. What surgical technical error most likely led to this complication?

. Placement of screws into the radiocarpal joint
. Plate placement distal to the watershed line
. Over-penetration of dorsal cortical screws
. Failure to repair the pronator quadratus
. Excessive radial inclination correction

Correct Answer & Explanation

. Plate placement distal to the watershed line

Explanation

Flexor pollicis longus (FPL) tendon rupture is a known complication of volar plating for distal radius fractures. It most commonly occurs due to prominent hardware placed distal to the watershed line, causing attritional wear of the tendon.

Question 1151

Topic: Wrist & Carpus

A 10-year-old girl with multiple hereditary exostoses presents for routine follow-up. Which of the following is the most classic forearm deformity associated with this condition?

. Relative overgrowth of the ulna leading to radial deviation
. Ulnar shortening with secondary radial bowing and ulnar deviation of the carpus
. Radial shortening with a positive ulnar variance
. Dorsal subluxation of the distal radioulnar joint (DRUJ) isolated without bowing
. Congenital radioulnar synostosis

Correct Answer & Explanation

. Ulnar shortening with secondary radial bowing and ulnar deviation of the carpus

Explanation

The classic forearm deformity in multiple hereditary exostoses (MHE) involves disproportionate growth restriction of the distal ulna. This leads to relative ulnar shortening, secondary bowing of the radius, ulnar deviation of the carpus, and possible radial head dislocation.

Question 1152

Topic: 7. Hand and Wrist

A 28-year-old male presents with dorsal wrist pain after a fall on an outstretched hand. Radiographs reveal a widened scapholunate interval of 4 mm. Which portion of the scapholunate interosseous ligament is the primary stabilizer and most crucial to repair?

. Volar
. Dorsal
. Proximal membranous
. Distal articular
. Radial

Correct Answer & Explanation

. Dorsal

Explanation

The scapholunate interosseous ligament has three components: dorsal, volar, and proximal membranous. The dorsal band is the thickest and biomechanically the most important primary stabilizer of the scapholunate articulation.

Question 1153

Topic: Hand Trauma & Infection

A patient presents with a crush injury to the fingertip resulting in a deep laceration extending into the proximal nail fold area, involving the structure primarily responsible for 90% of nail plate volume and thickness. Injury to this specific structure is most likely to result in which permanent nail deformity?

. Onycholysis
. Ridging/Dystrophy
. Split nail
. Hook nail (Pterygium Inversum)
. Chronic paronychia

Correct Answer & Explanation

. Split nail

Explanation

Correct Answer: CThe case explicitly states underSurgical Anatomy and Biomechanicsthat theGerminal Matrix (Proximal Matrix)is responsible for producing approximately 90% of the nail plate volume. It further notes that 'Injury to the germinal matrix often results in permanent nail deformities such as a split nail or an absent nail.' Therefore, a split nail is the most likely permanent deformity from an injury to this structure.Incorrect Options:A. Onycholysis:This is typically associated with injury to the sterile matrix, leading to non-adherence of the nail plate.B. Ridging/Dystrophy:While general nail dystrophy can occur from various injuries, ridging is more specifically linked to sterile matrix injury or chronic inflammation, not primarily germinal matrix laceration leading to a split.D. Hook nail (Pterygium Inversum):This is often associated with underlying bone malunion or specific nail bed scarring, not a direct consequence of germinal matrix laceration.E. Chronic paronychia:This is an inflammatory condition of the nail folds, often due to infection or irritation, not a direct deformity of the nail plate resulting from germinal matrix laceration.

Question 1154

Topic: Hand Trauma & Infection

A patient sustains a laceration primarily affecting the sterile matrix of the nail unit. Based on the anatomical description, which of the following is the most likely long-term consequence of an inadequately repaired injury to this specific structure?

. Complete absence of the nail plate.
. Permanent split nail.
. Nail plate dystrophy, non-adherence, or onycholysis.
. Pterygium formation (fusion of eponychium to nail bed).
. Chronic paronychia.

Correct Answer & Explanation

. Nail plate dystrophy, non-adherence, or onycholysis.

Explanation

Correct Answer: CUnder theSurgical Anatomy and Biomechanicssection, in theNail Bedsubsection, it states: 'Injury to the sterile matrix can lead to nail plate dystrophy, non-adherence, or onycholysis.' The sterile matrix provides adherence to the nail plate and contributes to its shape and contour.Incorrect Options:A. Complete absence of the nail plate:This is more likely with severe germinal matrix destruction.B. Permanent split nail:This is a classic consequence of germinal matrix injury.D. Pterygium formation:This is typically associated with eponychial fold injuries or severe scarring that causes the eponychium to adhere to the nail bed.E. Chronic paronychia:This is an inflammatory condition of the nail folds, not a direct consequence of sterile matrix laceration leading to nail plate deformity.

Question 1155

Topic: Nerve & Tendon
During a surgical reconstruction for a Blauth Type IIIA hypoplastic thumb, the surgeon performs a radical release of the adductor pollicis muscle to deepen the first web space. Which of the following neurovascular structures is at greatest risk of iatrogenic injury during this specific step?
. Superficial radial nerve
. Median nerve motor branch to the thenar muscles
. Deep palmar arch and ulnar nerve motor branch
. Radial artery in the anatomical snuffbox
. Anterior interosseous nerve

Correct Answer & Explanation

. Deep palmar arch and ulnar nerve motor branch

Explanation

The adductor pollicis muscle lies deep in the palm, and its release requires careful dissection in proximity to the deep palmar arch and the ulnar nerve motor branch. These structures are at risk during this specific step of the procedure.

Question 1156

Topic: 7. Hand and Wrist
A 2-year-old patient undergoes reconstruction for a Blauth Type IIIA hypoplastic thumb, including CMC joint stabilization using an FCR slip and an FDS ring finger tendon transfer for opposition. Post-operatively, the thumb is immobilized in a long arm thumb spica cast. Which of the following positions is critical for initial immobilization to protect the reconstruction and optimize long-term function?
. Wrist in neutral, thumb adducted, MCP and IP joints fully extended
. Wrist in 30 degrees flexion, thumb in maximal abduction, MCP and IP joints in full flexion
. Wrist in 20-30 degrees extension, thumb in maximal abduction and slight pronation, MCP 15-20 degrees flexion, IP slight flexion or neutral
. Wrist in full extension, thumb in neutral position, MCP and IP joints in 45 degrees flexion
. Wrist in 10 degrees ulnar deviation, thumb in adduction, MCP and IP joints in full extension

Correct Answer & Explanation

. Wrist in 20-30 degrees extension, thumb in maximal abduction and slight pronation, MCP 15-20 degrees flexion, IP slight flexion or neutral

Explanation

The wrist is typically held in 20-30 degrees of extension, the thumb is maximally abducted, the CMC joint is stabilized in abduction and slight pronation, the MCP joint is in 15-20 degrees of flexion, and the IP joint is in slight flexion or neutral. This position protects the web space, CMC stabilization, and tendon transfer.

Question 1157

Topic: 7. Hand and Wrist
A 10-month-old patient presents with a hypoplastic thumb characterized by a rudimentary digit connected to the hand only by a neurovascular pedicle, complete absence of intrinsic musculature, and a non-articulating metacarpal. Radiographs confirm severe skeletal deficiency. The parents are seeking the most functional long-term outcome. Based on the Blauth classification and the case's recommendations, what is the definitive management for this condition?
. First web space deepening with a dorsal rotation flap and CMC capsulodesis.
. FDS ring finger tendon transfer for opposition with K-wire stabilization.
. Observation with serial occupational therapy.
. Pollicization of the index finger.
. Distraction osteogenesis of the rudimentary metacarpal.

Correct Answer & Explanation

. Pollicization of the index finger.

Explanation

The description of a rudimentary digit connected to the hand only by a neurovascular pedicle, with complete absence of intrinsic musculature and a non-articulating metacarpal, matches the definition of a Blauth Type IIIB 'floating thumb'. Pollicization (transferring another digit, usually the index finger, to the thumb position) is the preferred option due to superior long-term functional and aesthetic outcomes for these severe deficiencies.

Question 1158

Topic: 7. Hand and Wrist
A 1-year-old patient is scheduled for reconstruction of a Blauth Type IIIA hypoplastic thumb. Pre-operative imaging includes standard AP, lateral, and oblique radiographs of the hand and wrist. Which of the following specific anatomical features is most critical to assess on these radiographs to guide the decision for reconstruction versus pollicization?
. The presence and ossification of the carpal bones.
. The integrity of the deep transverse metacarpal ligament.
. The size, shape, and articulation of the trapezium and first metacarpal.
. The presence of a Palmaris Longus tendon.
. The vascularity of the princeps pollicis artery.

Correct Answer & Explanation

. The size, shape, and articulation of the trapezium and first metacarpal.

Explanation

The case material emphasizes the importance of skeletal anatomy in guiding management. Specifically, assess the trapezium, first metacarpal, and phalanges for size, shape, and articulation. The stability and presence of sufficient skeletal elements, particularly the CMC joint formed by the trapezium and first metacarpal, are paramount for a functional reconstruction. If these are severely deficient or non-articulating (as in Blauth Type IIIB/IV), pollicization becomes the preferred option.

Question 1159

Topic: 7. Hand and Wrist
A 5-year-old patient with a Blauth Type IIIA hypoplastic thumb undergoes an FDS ring finger tendon transfer for opposition. The surgeon plans to route the tendon. According to the case material, which routing method is most commonly employed for this procedure?
. Through the interosseous membrane to the dorsal aspect of the thumb.
. Through the carpal tunnel, then radially to the thumb.
. Subcutaneously across the palm to the ulnar side of the thumb metacarpal.
. Deep to the adductor pollicis muscle.
. Around the radial artery in the anatomical snuffbox.

Correct Answer & Explanation

. Subcutaneously across the palm to the ulnar side of the thumb metacarpal.

Explanation

The case states: 'Subcutaneous Route (most common): A subcutaneous tunnel is created across the palm, from the point of FDS delivery to the ulnar side of the thumb metacarpal. This route minimizes scar tissue adherence to deep structures.'

Question 1160

Topic: 7. Hand and Wrist
A newborn presents with a hypoplastic thumb. Radiographs reveal an absent proximal half of the first metacarpal and an absent carpometacarpal joint. What is the most appropriate definitive management?
. Observation and physical therapy
. Opponensplasty, web-space release, and UCL reconstruction
. Distraction osteogenesis of the first metacarpal
. Index finger pollicization
. Vascularized second toe transfer

Correct Answer & Explanation

. Index finger pollicization

Explanation

This clinical and radiographic presentation defines a Blauth Type IIIB thumb hypoplasia, characterized by partial or complete absence of the proximal first metacarpal and an unstable/absent CMC joint. Index finger pollicization is the standard of care to provide a functional digit for pinch and grasp.

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