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7. Hand and Wrist MCQs

Practice Set 115 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 2281

Topic: Wrist & Carpus

A 55-year-old female presents with an inability to actively flex the interphalangeal joint of her thumb 8 months after undergoing volar plate fixation of a distal radius fracture. Radiographs show a healed fracture but the distal edge of the volar plate is positioned anterior to the watershed line. Which tendon is most likely ruptured due to attritional wear against the plate?

. Flexor carpi radialis (FCR)
. Flexor digitorum superficialis (FDS) to the index finger
. Flexor digitorum profundus (FDP) to the index finger
. Flexor pollicis longus (FPL)
. Extensor pollicis longus (EPL)

Correct Answer & Explanation

. Flexor pollicis longus (FPL)

Explanation

Placement of a volar plate distal to the watershed line of the distal radius places the prominent hardware in direct contact with the flexor tendons. The Flexor Pollicis Longus (FPL) tendon runs intimately over this area and is at the highest risk for attritional rupture when the plate is positioned too distally or stands proud of the bone (Soong Grade 2).

Question 2282

Topic: Nerve & Tendon

During an ulnar nerve transposition, a surgeon must release several potential sites of compression. The Arcade of Struthers is one such site and is defined as a fascial band extending from the:

. Medial intermuscular septum to the medial head of the triceps
. Bicipital aponeurosis to the pronator teres
. Medial epicondyle to the olecranon
. Supracondylar process to the medial epicondyle
. Osborne's ligament to the flexor carpi ulnaris heads

Correct Answer & Explanation

. Medial intermuscular septum to the medial head of the triceps

Explanation

The Arcade of Struthers is a fascial band located approximately 8 cm proximal to the medial epicondyle, extending from the medial intermuscular septum to the medial head of the triceps. It is a potential site of ulnar nerve compression. Do not confuse it with the ligament of Struthers, which can compress the median nerve.

Question 2283

Topic: Nerve & Tendon
A 25-year-old rugby player presents with an inability to actively flex the distal interphalangeal (DIP) joint of his ring finger after grabbing an opponent's jersey. Radiographs reveal a bony avulsion fragment localized at the level of the proximal interphalangeal (PIP) joint. According to the Leddy and Packer classification, what type of injury is this, and what is the typical status of the vincula?
. Type I, vincula intact
. Type I, vincula ruptured
. Type II, vincula intact
. Type III, vincula ruptured
. Type IV, vincula intact

Correct Answer & Explanation

. Type II, vincula intact

Explanation

This is a Leddy and Packer Type II 'Jersey finger' injury, where the Flexor Digitorum Profundus (FDP) tendon retracts to the level of the PIP joint. In Type II injuries, the vincula longus is typically intact, which preserves some blood supply and prevents the tendon from retracting into the palm (as seen in Type I injuries, where vincula are ruptured).

Question 2284

Topic: Wrist & Carpus

A 60-year-old female underwent volar locking plate fixation for a comminuted distal radius fracture. Eight months postoperatively, she returns complaining of a sudden inability to actively flex the interphalangeal joint of her thumb. Which of the following technical errors during the index surgery is the most likely culprit?

. Placement of the volar plate distal to the watershed line
. Prominent dorsal projection of distal locking screws
. Failure to repair the pronator quadratus muscle
. Over-reduction of the normal volar tilt
. Placement of the plate deep to the flexor carpi radialis tendon

Correct Answer & Explanation

. Placement of the volar plate distal to the watershed line

Explanation

Rupture of the flexor pollicis longus (FPL) tendon is a well-documented complication of volar plating of the distal radius. It occurs due to mechanical attrition and fraying of the tendon against the prominent distal edge of a plate that has been improperly positioned distal to the watershed line of the radius.

Question 2285

Topic: Wrist & Carpus

A 30-year-old laborer is diagnosed with a Scaphoid Nonunion Advanced Collapse (SNAC) wrist following an unrecognized scaphoid fracture five years prior. As the degenerative cascade of SNAC progresses through its predictable stages, which of the following joints is characteristically the LAST to develop arthritic changes?

. Radioscaphoid joint
. Scaphocapitate joint
. Capitolunate joint
. Lunotriquetral joint
. Radiolunate joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In both SLAC and SNAC wrist deformities, the radiolunate joint is characteristically spared from degenerative changes until the absolute end stages of the disease. This is because the lunate is concentrically congruent within the spherical lunate fossa of the radius, preserving normal load distribution and protecting the cartilage.

Question 2286

Topic: Nerve & Tendon

During a primary repair of a Zone II flexor tendon injury, extensive trauma to the flexor tendon sheath is noted. To prevent clinically significant bowstringing of the tendon, which of the following combinations of pulleys must be preserved or reconstructed as an absolute minimum?

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

Correct Answer & Explanation

. A2 and A4 pulleys

Explanation

The flexor tendon sheath in the fingers consists of five annular (A1-A5) and three cruciform (C1-C3) pulleys. The A2 and A4 pulleys arise directly from the periosteum of the proximal and middle phalanges, respectively. They are the most critical biomechanical pulleys for preventing tendon bowstringing during finger flexion. Loss of both A2 and A4 results in profound mechanical disadvantage and loss of digital motion.

Question 2287

Topic: 7. Hand and Wrist

A 35-year-old carpenter presents with weakness in his right hand. Examination reveals an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Sensation in the entire hand is intact. Which anomalous or muscular structure is most commonly implicated in the compression of the affected nerve?

. Ligament of Struthers
. Bicipital aponeurosis (Lacertus fibrosus)
. Transverse carpal ligament
. Gantzer's muscle (Accessory head of the flexor pollicis longus)
. Arcade of Frohse

Correct Answer & Explanation

. Gantzer's muscle (Accessory head of the flexor pollicis longus)

Explanation

The patient's presentation of isolated motor weakness to the FPL (thumb IP joint flexion) and FDP to the index finger, with preserved sensation, is classic for Anterior Interosseous Nerve (AIN) syndrome. The AIN is a motor branch of the median nerve. Compression frequently occurs in the proximal forearm. Gantzer's muscle (the accessory head of the flexor pollicis longus) is a well-known anomalous structure that can cause AIN entrapment. Other causes include the tendinous edge of the deep head of the pronator teres or the FDS aponeurotic arch. The ligament of Struthers affects the main median nerve (causing sensory findings), and the Arcade of Frohse compresses the posterior interosseous nerve.

Question 2288

Topic: 7. Hand and Wrist
A 45-year-old manual laborer presents with advanced Kienböck's disease, classified as Lichtman Stage IIIB. He is being evaluated for a proximal row carpectomy (PRC). Which of the following radiographic findings represents an absolute contraindication to performing a PRC?
. Scapholunate dissociation
. Osteoarthritis of the radiocarpal joint
. Advanced articular cartilage degeneration of the capitate head
. Ulnar minus variance greater than 2 mm
. Volar intercalated segment instability (VISI) deformity

Correct Answer & Explanation

. Advanced articular cartilage degeneration of the capitate head

Explanation

Proximal row carpectomy (PRC) involves excising the scaphoid, lunate, and triquetrum, allowing the capitate to articulate with the lunate fossa of the radius. Therefore, the articular surfaces of the proximal capitate and the lunate fossa of the distal radius must be preserved. Advanced degeneration of the capitate head or the lunate fossa is an absolute contraindication to PRC, and such patients are better managed with a scaphoid excision and four-corner fusion or total wrist arthrodesis.

Question 2289

Topic: 7. Hand and Wrist

The primary intrinsic blood supply to the flexor tendons within Zone II of the hand is provided by the vincula tendinum. Which of the following vascular structures directly supplies the vincula in this anatomical region?

. Proper digital arteries
. Common digital arteries
. Palmar metacarpal arteries
. Dorsal carpal arch
. Superficial palmar arch

Correct Answer & Explanation

. Proper digital arteries

Explanation

Within the fibro-osseous digital sheath (Zone II), the flexor tendons receive their blood supply intrinsically via the vincula tendinum (vincula brevia and longa) and extrinsically via synovial diffusion. The vincula are supplied by transverse communicating branches that arise directly from the proper digital arteries.

Question 2290

Topic: 7. Hand and Wrist

A 32-year-old female presents with chronic, firm, brawny dorsal edema over the metacarpals of her right hand. She reports it started after a minor contusion 6 months ago. Extensive investigations are negative for infection, inflammatory arthropathy, and complex regional pain syndrome. What is the most likely diagnosis, and what is the best initial management?

. Extensor tenosynovitis; surgical tenosynovectomy
. Secretan's syndrome; psychiatric evaluation and conservative care
. Lymphedema praecox; lymphatic bypass surgery
. Scleroderma; systemic corticosteroids
. Foreign body granuloma; excision

Correct Answer & Explanation

. Secretan's syndrome; psychiatric evaluation and conservative care

Explanation

Secretan's syndrome is a factitious condition characterized by chronic, firm, brawny edema over the dorsum of the hand, usually self-inflicted by repetitive blunt trauma or applying tourniquets. Treatment is conservative, including psychiatric evaluation, casting, and avoiding surgical intervention, which often worsens the condition or fails.

Question 2291

Topic: 7. Hand and Wrist

The major blood supply to the scaphoid enters through the dorsal ridge and supplies the proximal pole in a retrograde fashion. Which artery provides this primary vascular supply?

. Palmar carpal branch of the radial artery
. Superficial palmar branch of the radial artery
. Dorsal carpal branch of the radial artery
. Anterior interosseous artery
. Ulnar artery via the deep palmar arch

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The scaphoid receives 70-80% of its blood supply from the dorsal carpal branch of the radial artery, which enters at the dorsal ridge and flows retrogradely to supply the proximal pole. This delicate retrograde blood supply explains the high rate of avascular necrosis and nonunion seen in proximal pole scaphoid fractures.

Question 2292

Topic: 7. Hand and Wrist

During a flexor tendon repair in the hand, preserving the pulley system is crucial to prevent bowstringing and ensure efficient digit flexion. Which two annular pulleys are considered the most biomechanically essential and must be preserved or reconstructed?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 (arising from the proximal phalanx) and A4 (arising from the middle phalanx) are the major pulleys required to prevent bowstringing of the flexor tendons and maintain mechanical advantage. They are biomechanically the most important. A1, A3, and A5 arise from the volar plates of the MP, PIP, and DIP joints, respectively.

Question 2293

Topic: 7. Hand and Wrist

During a flexor tendon repair in Zone II of the hand, the surgeon meticulously manages the flexor tendon sheath to prevent postoperative bowstringing. Which two annular pulleys are biomechanically the most critical to preserve or reconstruct?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 (located over the proximal phalanx) and A4 (located over the middle phalanx) pulleys are the most crucial for preventing bowstringing of the flexor tendons and maintaining the mechanical advantage of the flexor system in the digits. They should be preserved or reconstructed whenever possible.

Question 2294

Topic: 7. Hand and Wrist

A 24-year-old male sustains a proximal pole fracture of the scaphoid. This region is at high risk for avascular necrosis due to its retrograde blood supply. Which of the following arteries provides the primary blood supply to the proximal 80% of the scaphoid?

. Superficial palmar arch
. Dorsal carpal branch of the radial artery
. Volar carpal branch of the ulnar artery
. Anterior interosseous artery
. Princeps pollicis artery

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The major blood supply to the scaphoid enters distally along the dorsal ridge via the dorsal carpal branch of the radial artery. It flows in a retrograde fashion to supply the proximal 80% of the bone, making proximal pole fractures particularly vulnerable to avascular necrosis.

Question 2295

Topic: Nerve & Tendon

A 45-year-old avid cyclist presents with intrinsic muscle weakness in his right hand. Sensation is decreased over the volar aspect of the little finger and the ulnar half of the ring finger, but normal over the dorsal ulnar aspect of the hand. Where is the most likely site of nerve compression?

. Cubital tunnel
. Zone 1 of Guyon's canal
. Zone 2 of Guyon's canal
. Zone 3 of Guyon's canal
. Arcade of Struthers

Correct Answer & Explanation

. Zone 1 of Guyon's canal

Explanation

Compression in Zone 1 of Guyon's canal (proximal to the bifurcation of the ulnar nerve) results in both motor (intrinsic weakness) and sensory (volar ulnar digits) deficits. The dorsal ulnar cutaneous nerve branches off proximal to the wrist; thus, dorsal sensation is spared, differentiating it from cubital tunnel syndrome. Zone 2 causes isolated motor deficits, and Zone 3 causes isolated sensory deficits.

Question 2296

Topic: Wrist & Carpus

In Scaphoid Nonunion Advanced Collapse (SNAC) of the wrist, which articulation is characteristically spared from degenerative changes, allowing for motion-preserving salvage procedures such as a four-corner fusion?

. Radioscaphoid joint
. Capitolunate joint
. Radiolunate joint
. Scaphotrapezial joint
. Capitohamate joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In both SNAC and SLAC (Scapholunate Advanced Collapse) wrist arthritis patterns, the radiolunate joint is characteristically spared from osteoarthritis. This occurs because the lunate maintains a congruent and concentric articulation with the lunate fossa of the radius. This preservation allows for salvage procedures like a four-corner fusion or proximal row carpectomy.

Question 2297

Topic: Hand Trauma & Infection

In the evaluation of a patient with suspected pyogenic flexor tenosynovitis, which of Kanavel's four classic signs is generally considered the earliest and most sensitive indicator of the condition?

. Fusiform swelling of the entire digit
. Flexed resting posture of the digit
. Tenderness localized to the flexor tendon sheath
. Severe pain with passive extension of the digit
. Erythema extending to the palmar crease

Correct Answer & Explanation

. Severe pain with passive extension of the digit

Explanation

Kanavel's four signs of pyogenic flexor tenosynovitis are: 1) fusiform swelling (sausage digit), 2) flexed resting posture, 3) tenderness along the flexor tendon sheath, and 4) excruciating pain with passive extension. Pain with passive extension is widely recognized as the earliest and most sensitive clinical sign of a flexor sheath infection.

Question 2298

Topic: Nerve & Tendon

A 45-year-old cyclist presents with isolated weakness of finger abduction and adduction, and an inability to cross his fingers. Sensation over the volar aspect of his small finger and the ulnar half of the ring finger is completely intact. Where is the most likely site of ulnar nerve compression?

. Cubital tunnel
. Guyon's canal - Zone 1
. Guyon's canal - Zone 2
. Guyon's canal - Zone 3
. Arcade of Struthers

Correct Answer & Explanation

. Guyon's canal - Zone 2

Explanation

Guyon's canal is divided into three zones. Zone 1 is proximal to the nerve bifurcation and contains both motor and sensory fibers; compression here causes mixed deficits. Zone 2 surrounds the deep motor branch; compression here causes isolated motor deficits of the ulnar-innervated intrinsic hand muscles. Zone 3 contains the superficial sensory branch; compression here causes isolated sensory deficits. 'Cyclist's palsy' frequently presents as an isolated motor deficit due to Zone 2 compression.

Question 2299

Topic: 7. Hand and Wrist

During an open carpal tunnel release, the transverse carpal ligament is systematically divided. Which of the following bony structures form the ulnar attachment of the transverse carpal ligament?

. Scaphoid tuberosity and trapezium ridge
. Hook of the hamate and pisiform
. Triquetrum and lunate
. Trapezoid and capitate
. Styloid process of the ulna

Correct Answer & Explanation

. Scaphoid tuberosity and trapezium ridge

Explanation

The transverse carpal ligament (flexor retinaculum) forms the roof of the carpal tunnel. It attaches radially to the scaphoid tuberosity and the crest of the trapezium, and ulnarly to the pisiform and the hook of the hamate.

Question 2300

Topic: Wrist & Carpus

Six months after open reduction and internal fixation of a distal radius fracture with a volar locking plate, the patient develops a sudden inability to actively extend the interphalangeal joint of the thumb. Which tendon is most likely injured, and what is the primary mechanism?

. Extensor pollicis longus (EPL); attritional rupture due to prominent dorsal screws
. Extensor pollicis brevis (EPB); impingement from the volar plate
. Flexor pollicis longus (FPL); attritional rupture over the watershed line
. Extensor carpi radialis longus (ECRL); iatrogenic transection during surgery
. Extensor pollicis longus (EPL); spontaneous rupture secondary to a previously non-displaced Lister's tubercle fracture

Correct Answer & Explanation

. Extensor pollicis longus (EPL); attritional rupture due to prominent dorsal screws

Explanation

The inability to actively extend the thumb interphalangeal joint indicates a rupture of the Extensor pollicis longus (EPL) tendon. In the setting of a previously placed volar plate, this complication is classically caused by excessively long screws protruding through the dorsal cortex, leading to attritional wear and eventual rupture of the EPL tendon.

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