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7. Hand and Wrist MCQs

Practice Set 110 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 2181

Topic: 7. Hand and Wrist

A 28-year-old carpenter suffers a laceration to the volar aspect of his index finger at the level of the proximal phalanx, resulting in a Zone II flexor tendon injury. To prevent functionally limiting bowstringing of the repaired flexor tendons, preservation or reconstruction of which two pulleys is absolutely biomechanically critical?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The flexor tendon sheath of the digits contains an annular and cruciate pulley system. The A2 pulley (located over the proximal phalanx) and the A4 pulley (located over the middle phalanx) are biomechanically the most important pulleys for preventing bowstringing of the flexor tendons and maintaining the mechanical advantage of digit flexion.

Question 2182

Topic: 7. Hand and Wrist

A patient presents with weakness in their dominant hand. Upon physical examination, they are asked to make an 'OK' sign by pinching the tips of their thumb and index finger together. Instead of a round circle, the patient forms a 'flat' pinch, exhibiting an inability to flex the interphalangeal (IP) joint of the thumb and the distal interphalangeal (DIP) joint of the index finger. Sensation in the hand is entirely normal. Which nerve is compressed, and what is the corresponding syndrome?

. Anterior interosseous nerve; AIN syndrome
. Posterior interosseous nerve; PIN syndrome
. Recurrent motor branch of the median nerve; Carpal tunnel syndrome
. Ulnar nerve; Cubital tunnel syndrome
. Median nerve; Pronator syndrome

Correct Answer & Explanation

. Anterior interosseous nerve; AIN syndrome

Explanation

The anterior interosseous nerve (AIN) is a pure motor branch of the median nerve that innervates the flexor pollicis longus (FPL), the flexor digitorum profundus (FDP) to the index and middle fingers, and the pronator quadratus. Loss of FPL and index FDP function results in the inability to flex the thumb IP joint and index DIP joint, leading to the classic positive 'OK' sign (Kiloh-Nevin sign). Pronator syndrome would have sensory deficits.

Question 2183

Topic: 7. Hand and Wrist

A patient presents with an inability to form an 'OK' sign with their thumb and index finger, instead forming a 'flat pinch'. Sensation in the hand is completely normal. Which of the following muscles is unaffected by this specific nerve palsy?

. Flexor pollicis longus
. Flexor digitorum profundus to the index finger
. Pronator quadratus
. Flexor carpi radialis
. Flexor digitorum profundus to the middle finger

Correct Answer & Explanation

. Flexor carpi radialis

Explanation

The Anterior Interosseous Nerve (AIN) is a pure motor branch of the median nerve. It innervates the flexor pollicis longus (FPL), the radial half of the flexor digitorum profundus (FDP to index and middle fingers), and the pronator quadratus. The flexor carpi radialis is innervated by the main branch of the median nerve proximal to the AIN take-off.

Question 2184

Topic: Hand Trauma & Infection

In a patient diagnosed with a 'skier's thumb', the mechanism of a Stener lesion involves the proximal stump of the torn ulnar collateral ligament (UCL) becoming anatomically trapped. Which structure interposes between the torn ends of the UCL?

. Adductor pollicis aponeurosis
. Abductor pollicis brevis tendon
. Extensor pollicis longus tendon
. Flexor pollicis longus tendon
. First dorsal interosseous muscle

Correct Answer & Explanation

. Adductor pollicis aponeurosis

Explanation

A Stener lesion occurs when the distal attachment of the thumb metacarpophalangeal (MCP) ulnar collateral ligament (UCL) avulses and displaces superficial to the adductor pollicis aponeurosis. This interposition prevents anatomical healing of the ligament and necessitates surgical repair.

Question 2185

Topic: Wrist & Carpus

A 42-year-old male presents with chronic wrist pain and a history of a scaphoid fracture 10 years ago. Radiographs reveal a scaphoid nonunion advanced collapse (SNAC) pattern with severe arthritis involving the radioscaphoid joint and the capitolunate joint. The radiolunate joint is perfectly preserved. What stage of SNAC wrist is this, and which procedure is most appropriate?

. Stage 1; Radial styloidectomy
. Stage 2; Scaphoid excision and four-corner fusion
. Stage 3; Scaphoid excision and four-corner fusion
. Stage 3; Proximal row carpectomy
. Stage 4; Total wrist arthrodesis

Correct Answer & Explanation

. Stage 3; Scaphoid excision and four-corner fusion

Explanation

SNAC staging: Stage 1 = Arthritis between the radial styloid and distal scaphoid. Stage 2 = Scaphocapitate arthritis. Stage 3 = Capitolunate arthritis. Stage 4 = Pancarpal arthritis (including radiolunate). This patient has capitolunate involvement (Stage 3). Scaphoid excision and four-corner fusion is the treatment of choice. Proximal row carpectomy (PRC) is contraindicated in Stage 3 SNAC/SLAC because PRC relies on a healthy proximal capitate articulating with the lunate fossa, which is destroyed in Stage 3.

Question 2186

Topic: 7. Hand and Wrist

A 28-year-old mechanic sustains a volar laceration to the proximal phalanx of his middle finger, completely transecting both the FDS and FDP tendons. This injury falls within flexor tendon Zone II. What is the anatomical landmark that defines the proximal boundary of Zone II?

. The distal interphalangeal joint
. The proximal edge of the A1 pulley
. The distal edge of the transverse carpal ligament
. The insertion of the FDS tendon on the middle phalanx
. The metacarpophalangeal joint line

Correct Answer & Explanation

. The proximal edge of the A1 pulley

Explanation

Flexor tendon Zone II (historically called 'no man's land' due to the poor outcomes of early repairs) extends from the proximal edge of the A1 pulley (at the level of the distal palmar crease) to the insertion of the Flexor Digitorum Superficialis (FDS) tendon on the middle phalanx. Both the FDS and FDP run together in a tight fibro-osseous sheath in this zone.

Question 2187

Topic: 7. Hand and Wrist

In order to prevent bowstringing of the flexor tendons in the fingers, which combination of pulleys is biomechanically the most critical to preserve during hand surgery?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The flexor tendon sheath in the fingers consists of a series of annular (A) and cruciate (C) pulleys. The A2 and A4 pulleys are the major biomechanical pulleys that arise from the periosteum of the proximal and middle phalanges, respectively. They are the most critical in preventing bowstringing of the flexor tendons during digit flexion and must be preserved or reconstructed.

Question 2188

Topic: 7. Hand and Wrist

A cyclist complains of numbness in the ring and small fingers and weakness in hand grip. Examination reveals a positive Froment's sign and decreased sensation over the volar aspect of the fifth digit, but normal sensation over the dorsal ulnar aspect of the hand. Where is the most likely site of compression?

. Cubital tunnel
. Canal of Guyon (Zone 1)
. Canal of Guyon (Zone 2)
. Canal of Guyon (Zone 3)
. Arcade of Struthers

Correct Answer & Explanation

. Canal of Guyon (Zone 1)

Explanation

The preservation of sensation over the dorsal ulnar hand indicates that the dorsal ulnar cutaneous nerve is spared, localizing the lesion distal to the forearm (i.e., at the wrist). Compression at Guyon's canal Zone 1 involves the main ulnar nerve trunk before it bifurcates, causing both motor weakness (positive Froment's sign, deep branch) and sensory deficits on the volar ulnar digits (superficial branch). Zone 2 compression is purely motor; Zone 3 is purely sensory.

Question 2189

Topic: Wrist & Carpus

A 65-year-old female undergoes volar locked plating for a displaced distal radius fracture. Three months postoperatively, she presents with an inability to extend her thumb at the interphalangeal joint. What is the most likely iatrogenic cause of this complication in the setting of volar plating?

. Vascular compromise to the tendon at Lister's tubercle
. Prominent distal screws penetrating the dorsal cortex
. Excessive retraction during the volar surgical approach
. Direct injury from the drill bit on the volar side
. Attrition of the tendon over a prominent volar plate

Correct Answer & Explanation

. Prominent distal screws penetrating the dorsal cortex

Explanation

Rupture of the extensor pollicis longus (EPL) tendon following volar plating of the distal radius is most commonly caused by prominent distal screws penetrating the dorsal cortex. The EPL runs in the third dorsal compartment, directly over the distal radius. Volar plate prominence or improper positioning on the watershed line typically causes flexor tendon ruptures (e.g., FPL), whereas dorsal screw prominence causes extensor tendon ruptures.

Question 2190

Topic: 7. Hand and Wrist
A 45-year-old male laborer presents with chronic wrist pain and is diagnosed with a scaphoid nonunion advanced collapse (SNAC) pattern. Radiographs reveal osteoarthritis involving the radial styloid, the entire scaphoid facet, and the capitolunate joint. The radiolunate joint is preserved. Which of the following surgical options is relatively contraindicated in this patient?
. Proximal row carpectomy (PRC)
. Scaphoid excision and four-corner arthrodesis
. Total wrist arthrodesis
. Total wrist arthroplasty
. Denervation of the wrist

Correct Answer & Explanation

. Scaphoid excision and four-corner arthrodesis

Explanation

This patient has a Stage III SNAC wrist (involvement of the capitolunate joint). Proximal row carpectomy (PRC) relies on a preserved cartilage articulation between the lunate fossa of the radius and the proximal head of the capitate. Because the capitolunate joint is arthritic, the capitate head is damaged, making PRC contraindicated as it would result in a painful capitate-radius articulation. Scaphoid excision with four-corner fusion is the appropriate motion-preserving procedure in this setting, as it spares the radiolunate joint.

Question 2191

Topic: Nerve & Tendon

A 24-year-old avid golfer presents with weakness of the intrinsic muscles of the hand. Sensation is perfectly normal over the entire volar and dorsal aspect of the hand and digits. A fracture of the hook of the hamate is identified. In which zone of Guyon's canal is the ulnar nerve compression most likely occurring?

. Zone 1
. Zone 2
. Zone 3
. Zone 4
. Zone 5

Correct Answer & Explanation

. Zone 3

Explanation

Guyon's canal is divided into 3 zones. Zone 1 is proximal to the bifurcation and contains both motor and sensory fibers. Zone 2 surrounds the deep motor branch of the ulnar nerve after it bifurcates and passes adjacent to the hook of the hamate; compression here causes isolated motor weakness of the ulnar-innervated intrinsics. Zone 3 encompasses the superficial sensory branch; compression here causes isolated sensory deficits. Hook of the hamate fractures typically compress Zone 2.

Question 2192

Topic: 7. Hand and Wrist

A patient with a chronic low ulnar nerve palsy presents with a classic claw hand deformity. During physical examination, the examiner blocks the metacarpophalangeal (MCP) joints in flexion, and the patient is then able to actively extend the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints. This finding indicates:

. A positive Froment sign
. An incompetent central slip
. A positive Bouvier test demonstrating that extrinsic extensor force is sufficient to extend the IP joints
. Severe PIP joint capsular contracture
. Recovery of the interosseous muscles

Correct Answer & Explanation

. A positive Bouvier test demonstrating that extrinsic extensor force is sufficient to extend the IP joints

Explanation

This is a positive Bouvier test. In an intrinsic-minus hand, the extrinsic extensors hyperextend the MCP joint, dissipating the force needed to extend the IP joints. By blocking MCP hyperextension, the test proves the extensor digitorum communis (EDC) can successfully extend the IP joints, meaning the patient may benefit from a simple MCP flexion block procedure (e.g., Zancolli lasso).

Question 2193

Topic: 7. Hand and Wrist

During a volar Henry approach to the distal radius, an incision is made over the flexor carpi radialis (FCR) sheath. Which of the following neural structures is at greatest risk of iatrogenic injury if the dissection mistakenly proceeds ulnar to the FCR tendon?

. Palmar cutaneous branch of the median nerve
. Main trunk of the median nerve
. Anterior interosseous nerve
. Superficial branch of the radial nerve
. Ulnar nerve

Correct Answer & Explanation

. Palmar cutaneous branch of the median nerve

Explanation

The palmar cutaneous branch of the median nerve arises approximately 5 cm proximal to the wrist crease and travels ulnar to the FCR tendon. Incising the FCR sheath and retracting the tendon ulnarly protects this nerve. Straying ulnar to the FCR during superficial dissection places the nerve at high risk.

Question 2194

Topic: 7. Hand and Wrist
A 28-year-old female presents with chronic wrist pain and is diagnosed with Kienböck's disease. Radiographs reveal increased sclerosis of the lunate without fragmentation, no carpal collapse, and an ulnar variance of -3 mm. According to the Lichtman classification, what is the most appropriate surgical intervention?
. Proximal row carpectomy
. Scaphotrapeziotrapezoid (STT) arthrodesis
. Radial shortening osteotomy
. Total wrist arthrodesis
. Lunate excision without replacement

Correct Answer & Explanation

. Radial shortening osteotomy

Explanation

The patient has Lichtman Stage II Kienböck's disease (sclerosis, no collapse) with negative ulnar variance. Joint leveling procedures, such as a radial shortening osteotomy, are the treatment of choice to decompress the lunate and halt disease progression.

Question 2195

Topic: 7. Hand and Wrist

In Dupuytren's disease, the spiral cord is frequently responsible for proximal interphalangeal (PIP) joint flexion contractures. As the spiral cord matures and contracts, how does it anatomically displace the digital neurovascular bundle?

. Superficial (volar) and central (midline)
. Deep (dorsal) and lateral
. Superficial (volar) and lateral
. Deep (dorsal) and central (midline)
. It remains in its native anatomical position

Correct Answer & Explanation

. Superficial (volar) and central (midline)

Explanation

The spiral cord in Dupuytren's contracture consists of the pretendinous band, spiral band, lateral digital sheet, and Grayson's ligament. As it contracts, it wraps around the neurovascular bundle, displacing it superficially (volar) and centrally (towards the midline), placing it at severe risk during surgical fasciectomy.

Question 2196

Topic: 7. Hand and Wrist

Following primary surgical repair of an acute flexor tendon laceration in the hand, the tendon undergoes distinct phases of healing. During which time frame is the repair mechanically at its weakest, making it most susceptible to iatrogenic rupture?

. 0 to 4 days
. 5 to 21 days
. 28 to 42 days
. 6 to 8 weeks
. 3 to 6 months

Correct Answer & Explanation

. 5 to 21 days

Explanation

Tendon repair strength dips below its initial surgical holding strength between 5 and 21 days postoperatively. This occurs during the transition from the inflammatory phase to the early fibroblastic phase, where collagen degradation outpaces new collagen synthesis, causing the tendon ends to soften.

Question 2197

Topic: 7. Hand and Wrist

During an EMG/NCS for suspected carpal tunnel syndrome, the amplitude of the compound muscle action potential (CMAP) of the thenar muscles is paradoxically higher with proximal median nerve stimulation at the elbow than with distal stimulation at the wrist. What is the most likely anatomic explanation for this finding?

. Riche-Cannieu anastomosis
. Martin-Gruber anastomosis
. Marinacci communication
. Berrettini anastomosis
. Severe focal demyelination at the carpal tunnel

Correct Answer & Explanation

. Martin-Gruber anastomosis

Explanation

A Martin-Gruber anastomosis involves anomalous motor fibers crossing from the median nerve to the ulnar nerve in the proximal forearm. Proximal median nerve stimulation at the elbow captures these fibers before they cross over, generating a robust thenar CMAP. Distal median nerve stimulation at the wrist misses these crossed fibers (which are now in the ulnar nerve), resulting in a lower CMAP amplitude.

Question 2198

Topic: 7. Hand and Wrist

The vincula brevia and vincula longa are critical for providing the vascular supply to the flexor tendons within the digital fibrous sheath. These vincula are direct branches originating from which of the following vessels?

. Common digital arteries
. Proper digital arteries
. Superficial palmar arch
. Princeps pollicis artery
. Radial artery branches at the wrist

Correct Answer & Explanation

. Proper digital arteries

Explanation

The proper digital arteries run longitudinally along the digits and give off small transverse branches that penetrate the flexor sheath to supply the flexor tendons via the vincula longa and vincula brevia.

Question 2199

Topic: 7. Hand and Wrist
A 32-year-old manual laborer presents with chronic, progressive dorsal wrist pain and decreased grip strength. Radiographs reveal sclerosis and early collapse of the lunate, but the overall carpal height is maintained, and there is no scaphoid ring sign. Ulnar variance is negative (-2 mm). What is the most appropriate surgical intervention?
. Proximal row carpectomy
. Four-corner fusion
. Total wrist arthrodesis
. Radial shortening osteotomy
. Lunate excision alone

Correct Answer & Explanation

. Radial shortening osteotomy

Explanation

The patient has Kienböck's disease (avascular necrosis of the lunate), Lichtman Stage II or early IIIa (collapse without fixed scaphoid rotation or significant carpal height loss). In the presence of negative ulnar variance, a joint-leveling procedure such as a radial shortening osteotomy is the preferred treatment to decrease the compressive forces on the lunate, allowing for possible revascularization.

Question 2200

Topic: 7. Hand and Wrist
A 55-year-old manual laborer presents with advanced Stage III SLAC wrist (scapholunate advanced collapse). Radiographs show complete loss of articular cartilage on the proximal head of the capitate, as well as radioscaphoid arthritis. The radiolunate joint is preserved. What is the most appropriate surgical treatment?
. Proximal row carpectomy (PRC)
. Scaphoid excision and four-corner fusion
. Total wrist arthroplasty
. Radioscapholunate fusion
. Darrach procedure

Correct Answer & Explanation

. Scaphoid excision and four-corner fusion

Explanation

Stage III SLAC wrist involves arthritis of the radioscaphoid and capitolunate joints. Because the proximal capitate articular surface is diseased, a Proximal Row Carpectomy (PRC) is strictly contraindicated (as it relies on a healthy capitate head articulating with the lunate fossa). Therefore, scaphoid excision and four-corner fusion (capitate, hamate, lunate, triquetrum) is the procedure of choice.

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