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7. Hand and Wrist MCQs

Practice Set 238 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 4741

Topic: 7. Hand and Wrist

A patient with a ganglion cyst in Guyon's canal complains of hand weakness and paresthesias. Which of the following clinical findings indicates that the ulnar nerve compression is occurring at the wrist (Guyon's canal) rather than at the elbow (Cubital Tunnel)?

. Weakness of the adductor pollicis muscle
. Positive Froment's sign
. Sparing of sensation over the dorsal ulnar aspect of the hand
. Paresthesia in the volar small finger
. Wasting of the first dorsal interosseous muscle

Correct Answer & Explanation

. Sparing of sensation over the dorsal ulnar aspect of the hand

Explanation

The dorsal ulnar cutaneous nerve (DUCN) branches off the main ulnar nerve approximately 5-8 cm proximal to the wrist crease. Therefore, compression at Guyon's canal spares the DUCN, leaving sensation intact over the dorsal ulnar hand, which differentiates it from cubital tunnel syndrome.

Question 4742

Topic: 7. Hand and Wrist

In a complete tear of the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal joint, a Stener lesion may prevent non-operative healing. Which structure is interposed between the ruptured UCL and its insertion site on the proximal phalanx?

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

Correct Answer & Explanation

. Adductor pollicis aponeurosis

Explanation

A Stener lesion occurs when the distal end of the ruptured UCL slips superficial to the adductor pollicis aponeurosis. The interposition of the adductor aponeurosis mechanically blocks the UCL from healing back to its anatomic insertion on the proximal phalanx, necessitating surgical repair.

Question 4743

Topic: 7. Hand and Wrist

Transverse fractures of the proximal phalanx shaft characteristically angulate with a volar apex (dorsal angulation). Which specific muscle forces are primarily responsible for this consistent deformity pattern?

. Lumbricals flexing the proximal fragment and FDP flexing the distal fragment
. Interossei flexing the proximal fragment and the central slip extending the distal fragment
. FDS flexing the distal fragment and EDC extending the proximal fragment
. Adductor pollicis flexing the proximal fragment and lateral bands extending the distal fragment
. FDP extending the distal fragment and lumbricals extending the proximal fragment

Correct Answer & Explanation

. Interossei flexing the proximal fragment and the central slip extending the distal fragment

Explanation

In proximal phalanx fractures, the intrinsic interossei insert on the base of the proximal phalanx and pull the proximal fragment into flexion. The central slip of the extensor mechanism attaches to the base of the middle phalanx, extending the distal fragment, collectively causing an apex volar (dorsal) angulation.

Question 4744

Topic: Nerve & Tendon

A 45-year-old mechanic presents with cold intolerance, pain, and a pulsatile mass in the hypothenar eminence. An Allen's test indicates delayed capillary refill in the ulnar digits. Ulnar Hammer Syndrome is suspected. This condition involves thrombosis or aneurysm of the ulnar artery resulting from repetitive microtrauma against which bony structure?

. Pisiform
. Scaphoid tubercle
. Hook of hamate
. Lister's tubercle
. Ulnar styloid

Correct Answer & Explanation

. Hook of hamate

Explanation

Ulnar Hammer Syndrome occurs due to repetitive compressive trauma to the ulnar artery within Guyon's canal. The artery is mechanically crushed against the underlying hook of the hamate, which acts as an anvil, leading to thrombosis, intimal damage, or pseudoaneurysm formation.

Question 4745

Topic: 7. Hand and Wrist

In severe, long-standing Carpal Tunnel Syndrome with profound thenar atrophy, an opponensplasty may be performed concurrently with carpal tunnel release. The Camitz transfer is frequently selected for this purpose. Which tendon is utilized as the donor in a classic Camitz transfer?

. Flexor digitorum superficialis to the ring finger
. Extensor indicis proprius
. Palmaris longus
. Abductor pollicis longus
. Flexor carpi radialis

Correct Answer & Explanation

. Palmaris longus

Explanation

The Camitz transfer uses the Palmaris longus tendon, extended with a strip of palmar fascia, and routes it subcutaneously to the insertion of the Abductor Pollicis Brevis (APB). It provides excellent thumb abduction but is less optimal for true opposition compared to an FDS transfer.

Question 4746

Topic: 7. Hand and Wrist
A 30-year-old manual laborer presents with chronic wrist pain and is diagnosed with Stage IIIB Kienböck's disease. According to the Lichtman classification, which of the following best describes the morphologic findings of Stage IIIB?
. Lunate sclerosis without any architectural collapse.
. Lunate collapse and fragmentation with normal carpal height and alignment.
. Lunate collapse accompanied by scaphoid rotary subluxation and loss of carpal height.
. Advanced pancarpal osteoarthritis involving the midcarpal and radiocarpal joints.
. Cystic changes in the lunate with a negative ulnar variance but normal lunate shape.

Correct Answer & Explanation

. Lunate collapse accompanied by scaphoid rotary subluxation and loss of carpal height.

Explanation

Lichtman Stage IIIB Kienböck's disease is characterized by lunate fragmentation and collapse along with fixed carpal instability (typically scaphoid flexion/rotary subluxation) and a resultant decrease in carpal height. Stage IIIA has lunate collapse but maintains normal carpal alignment.

Question 4747

Topic: Wrist & Carpus

During surgical reduction of a Galeazzi fracture (distal radius shaft fracture with distal radioulnar joint (DRUJ) dislocation), the DRUJ remains irreducible despite anatomic fixation of the radius. Which anatomical structure is the most common cause of an irreducible DRUJ block in this scenario?

. Flexor carpi radialis tendon
. Extensor carpi ulnaris (ECU) tendon
. Pronator quadratus muscle belly
. Superficial branch of the radial nerve
. Triangular fibrocartilage complex (TFCC) central articular disc

Correct Answer & Explanation

. Extensor carpi ulnaris (ECU) tendon

Explanation

In a Galeazzi fracture-dislocation, if the DRUJ cannot be reduced after the radius is fixed, the most common soft-tissue block is the interposition of the Extensor Carpi Ulnaris (ECU) tendon into the DRUJ, necessitating open reduction to extract the tendon.

Question 4748

Topic: 7. Hand and Wrist
A 24-year-old rock climber presents with a flexor tendon injury to the middle finger. Radiographs reveal a large bony avulsion fragment from the volar base of the distal phalanx resting over the middle phalanx. This characterizes a Leddy-Packer Type III injury. At which pulley is the proximal retraction of this tendon-bone unit classically blocked?
. A1 pulley
. A2 pulley
. A3 pulley
. A4 pulley
. A5 pulley

Correct Answer & Explanation

. A4 pulley

Explanation

In a Leddy-Packer Type III flexor digitorum profundus (FDP) avulsion, a large bony fragment is avulsed with the tendon. Because of its size, this bony fragment cannot pass through the A4 pulley. It becomes incarcerated at the A4 pulley, located at the level of the middle phalanx.

Question 4749

Topic: 7. Hand and Wrist

A 35-year-old man presents with chronic wrist pain years after an unrecognized fall. Radiographs demonstrate a scaphoid nonunion with radioscaphoid arthritis, but the capitolunate joint remains completely spared. What is the correct classification and most appropriate surgical option?

. SNAC Stage 1; Radial styloidectomy
. SNAC Stage 2; Proximal row carpectomy or four-corner fusion
. SNAC Stage 3; Proximal row carpectomy
. SNAC Stage 3; Total wrist arthrodesis
. SNAC Stage 4; Total wrist arthrodesis

Correct Answer & Explanation

. SNAC Stage 2; Proximal row carpectomy or four-corner fusion

Explanation

Scaphoid Nonunion Advanced Collapse (SNAC) is staged by arthritis location: Stage 1 involves the radial styloid; Stage 2 involves the entire scaphoid fossa; Stage 3 involves the capitolunate joint; Stage 4 involves the entire carpus. Because the capitolunate joint is spared, this is Stage 2. Proximal row carpectomy (PRC) or four-corner fusion (4CF) are standard treatments for Stage 2 SNAC wrists. PRC requires a preserved proximal capitate articular surface.

Question 4750

Topic: Nerve & Tendon

A 45-year-old cyclist presents with weakness in thumb adduction and finger abduction/adduction. Sensation over the entire small finger is completely normal, and hypothenar muscle bulk and strength are intact. Which zone of Guyon's canal is the most likely site of ulnar nerve compression?

. Zone 1
. Zone 2, proximal to the hypothenar motor branches
. Zone 2, distal to the hypothenar motor branches
. Zone 3
. Cubital tunnel

Correct Answer & Explanation

. Zone 2, distal to the hypothenar motor branches

Explanation

Guyon's canal is divided into 3 zones. Zone 1 contains the mixed motor/sensory nerve. Zone 2 contains the deep motor branch. Zone 3 contains the superficial sensory branch. A lesion in Zone 2 causes isolated motor weakness. Because the hypothenar muscles are spared, the lesion must be in Zone 2 distal to the takeoff of the hypothenar motor branches, affecting only the interossei and adductor pollicis.

Question 4751

Topic: 7. Hand and Wrist
A newborn is evaluated for a congenital hand anomaly. The right thumb is present but highly hypoplastic, lacks any proximal bony support (absent metacarpal base), has no carpometacarpal joint, and is attached to the hand only by a soft tissue skin pedicle. According to the Blauth classification, what type of thumb hypoplasia is this?
. Type II
. Type IIIA
. Type IIIB
. Type IV
. Type V

Correct Answer & Explanation

. Type IV

Explanation

This describes a 'pouce flottant' or floating thumb, which is Blauth Type IV. Type II has a hypoplastic metacarpal and intrinsic absence but a stable CMC. Type III has a severely hypoplastic metacarpal (IIIA has a stable CMC; IIIB has an absent proximal metacarpal and unstable CMC). Type V is complete absence of the thumb.

Question 4752

Topic: 7. Hand and Wrist

Which of the following pathologic anatomic structures is considered the primary tethering force responsible for the characteristic deformity seen in Madelung deformity?

. Oblique retinacular ligament
. Vickers ligament
. Osborne's fascia
. Arcade of Frohse
. Ligament of Struthers

Correct Answer & Explanation

. Vickers ligament

Explanation

Madelung deformity is characterized by premature closure of the volar-ulnar distal radial physis. This is associated with a thick, tethering ligament known as Vickers ligament, which runs from the distal radius to the lunate, restricting growth and causing the classic volar and ulnar tilt of the distal radius articular surface.

Question 4753

Topic: 7. Hand and Wrist
A 28-year-old manual laborer presents with wrist pain. Radiographs demonstrate ulnar minus variance and sclerosis of the lunate with fragmentation. However, the scaphoid is not flexed, and carpal height is maintained. What is the Lichtman stage and most appropriate surgical treatment?
. Stage II; Proximal row carpectomy
. Stage IIIA; Radial shortening osteotomy
. Stage IIIB; Scaphotrapeziotrapezoid (STT) fusion
. Stage IV; Total wrist arthrodesis
. Stage IIIA; Lunate excision and silastic replacement

Correct Answer & Explanation

. Stage IIIA; Radial shortening osteotomy

Explanation

The patient has Kienböck's disease. Sclerosis with fragmentation but no carpal collapse (maintained carpal height, scaphoid not flexed) is Lichtman Stage IIIA. In a patient with ulnar negative variance, a joint-leveling procedure such as a radial shortening osteotomy is the most highly recommended treatment to unload the lunate.

Question 4754

Topic: 7. Hand and Wrist

During flexor tendon repair in the hand, preserving the pulley system is critical to prevent tendon bowstringing. Which two annular pulleys are considered the most mechanically essential 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 A2 (located over the proximal phalanx) and A4 (located over the middle phalanx) pulleys are the most biomechanically critical for preventing bowstringing of the flexor tendons and maintaining the moment arm for normal finger flexion.

Question 4755

Topic: 7. Hand and Wrist

During a fasciectomy for Dupuytren's contracture of the ring finger, the surgeon notes that the digital neurovascular bundle is displaced centrally and superficially. Which pathologic cord is responsible for this dangerous displacement?

. Pretendinous cord
. Central cord
. Spiral cord
. Natatory cord
. Lateral cord

Correct Answer & Explanation

. Spiral cord

Explanation

The spiral cord is formed by the amalgamation of the pretendinous band, spiral band, lateral digital sheet, and Grayson's ligament. As it contracts, it pulls the neurovascular bundle toward the midline (central) and superficially, placing it at high risk of iatrogenic injury during surgical excision.

Question 4756

Topic: Wrist & Carpus

A 60-year-old woman with a 20-year history of rheumatoid arthritis presents with a sudden inability to flex the interphalangeal joint of her thumb. She denies acute trauma. This presentation (Mannerfelt syndrome) is most classically caused by attrition of the flexor pollicis longus (FPL) tendon over which bony prominence?

. Lister's tubercle
. Volar osteophyte of the scaphoid
. Hook of the hamate
. Volar lip of the distal radius
. Trapezium

Correct Answer & Explanation

. Volar osteophyte of the scaphoid

Explanation

Mannerfelt syndrome in rheumatoid arthritis refers to the spontaneous rupture of the flexor pollicis longus (FPL) tendon. It is most commonly caused by attrition of the tendon as it glides over a sharp, volar osteophyte originating from the scaphoid (often at the STT joint).

Question 4757

Topic: 7. Hand and Wrist

A 32-year-old basketball player jammed his finger and presents 4 weeks later with PIP joint flexion and DIP joint extension. Which of the following best describes the underlying anatomic pathophysiology of this Boutonniere deformity?

. Attenuation of the central slip with dorsal subluxation of the lateral bands
. Attenuation of the central slip with volar subluxation of the lateral bands
. Rupture of the terminal extensor tendon with retraction
. Rupture of the flexor digitorum profundus (FDP)
. Contracture of the oblique retinacular ligament

Correct Answer & Explanation

. Attenuation of the central slip with volar subluxation of the lateral bands

Explanation

A Boutonniere deformity is caused by rupture or attenuation of the central slip of the extensor tendon at its insertion on the middle phalanx. This allows the lateral bands to subluxate volarly (palmar) to the axis of rotation of the PIP joint, turning them into PIP flexors while continuing to extend the DIP joint.

Question 4758

Topic: 7. Hand and Wrist

When planning surgical release for a child with congenital simple syndactyly of the middle and ring fingers, which of the following surgical principles is correct?

. The release should be performed using a straight midline incision.
. Skin grafting is almost never required if local flaps are designed correctly.
. A zigzag incision pattern (e.g., Bruner or Z-plasties) should be utilized to prevent longitudinal scar contracture.
. Surgery should ideally be performed in the first 2 months of life to prevent joint contractures.
. The neurovascular bundles routinely bifurcate very proximally and are rarely at risk.

Correct Answer & Explanation

. A zigzag incision pattern (e.g., Bruner or Z-plasties) should be utilized to prevent longitudinal scar contracture.

Explanation

In syndactyly release, zigzag incisions are mandatory to prevent longitudinal linear scar contracture, which can lead to severe flexion deformities as the child grows. Full-thickness skin grafts are almost always required to cover the defects left by the separated digits. Surgery is typically delayed until 12-18 months, except for border digits (thumb/index or ring/small) which may be done earlier.

Question 4759

Topic: 7. Hand and Wrist

A patient sustained a forearm crush injury and presents with inability to extend the fingers at the MCP joints and inability to extend the thumb. However, wrist extension is preserved, though the wrist deviates radially during the effort. Sensation in the hand is completely normal. Which nerve is injured?

. High radial nerve
. Posterior interosseous nerve (PIN)
. Anterior interosseous nerve (AIN)
. Superficial radial nerve
. Ulnar nerve

Correct Answer & Explanation

. Posterior interosseous nerve (PIN)

Explanation

The Posterior Interosseous Nerve (PIN) is a pure motor branch of the radial nerve. Injury causes loss of finger extension (EDC) and thumb extension (EPL). Wrist extension is preserved because the extensor carpi radialis longus (ECRL) is innervated by the radial nerve proper proximal to the PIN bifurcation. Radially deviated wrist extension occurs due to loss of the extensor carpi ulnaris (ECU), which is PIN innervated.

Question 4760

Topic: Nerve & Tendon

A 40-year-old man cannot make an 'OK' sign, instead forming a flat pinch between his thumb and index finger pads. His sensation is normal. Which of the following muscles is strictly spared in this specific nerve compression syndrome?

. Flexor pollicis longus (FPL)
. Flexor digitorum profundus (FDP) to the index finger
. Flexor digitorum profundus (FDP) to the middle finger
. Pronator quadratus
. Flexor digitorum superficialis (FDS)

Correct Answer & Explanation

. Flexor digitorum superficialis (FDS)

Explanation

The patient has Anterior Interosseous Nerve (AIN) syndrome, evidenced by the positive 'OK' sign (loss of FPL and FDP to the index finger). The AIN supplies the FPL, the FDP to the index and middle fingers, and the pronator quadratus. The Flexor Digitorum Superficialis (FDS) is innervated by the main branch of the median nerve in the proximal forearm, before the AIN branches off, and is therefore spared.

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