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7. Hand and Wrist MCQs

Practice Set 114 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 2261

Topic: Nerve & Tendon

During surgical repair of a Zone II flexor tendon injury, maintaining the integrity of the A2 and A4 pulleys is crucial to prevent bowstringing. If the A2 pulley is inadvertently excised, what is the most significant biomechanical consequence regarding the function of the flexor tendon?

. Decreased moment arm
. Decreased required tendon excursion to achieve full digit flexion
. Increased required tendon excursion to achieve full digit flexion
. Increased active grip strength
. Decreased passive resistance to extension

Correct Answer & Explanation

. Increased required tendon excursion to achieve full digit flexion

Explanation

The flexor pulleys keep the tendon closely applied to the bone. If the A2 or A4 pulley is excised, the tendon bowstrings away from the center of rotation of the joint. This increases the moment arm. Biomechanically, an increased moment arm means that a greater length of tendon excursion is required to achieve the same angular range of motion. Because the muscle's excursion is finite, this often results in incomplete active finger flexion.

Question 2262

Topic: 7. Hand and Wrist

A 34-year-old female presents with numbness and tingling in the radial three-and-a-half digits of her right hand, along with volar forearm pain. Which of the following clinical findings most specifically distinguishes Pronator Syndrome from Carpal Tunnel Syndrome?

. Positive Tinel's sign at the wrist crease
. Wasting of the thenar eminence musculature
. Numbness over the palmar aspect of the thenar eminence
. Exacerbation of symptoms that awaken the patient at night
. Weakness of the flexor pollicis brevis

Correct Answer & Explanation

. Numbness over the palmar aspect of the thenar eminence

Explanation

The palmar cutaneous branch of the median nerve provides sensation to the skin over the thenar eminence. It branches from the median nerve proximal to the carpal tunnel and travels superficial to the transverse carpal ligament. Therefore, sensation over the thenar eminence is spared in Carpal Tunnel Syndrome but is diminished in more proximal compression neuropathies like Pronator Syndrome.

Question 2263

Topic: Wrist & Carpus

A 50-year-old female presents with a sudden inability to actively flex the interphalangeal joint of her thumb. Three years prior, she underwent volar plate fixation of a distal radius fracture. The spontaneous rupture of the flexor pollicis longus (FPL) tendon in this setting is most commonly associated with which of the following intraoperative technical errors?

. Excessive dorsal screw prominence
. Volar plate placement distal to the watershed line
. Intra-articular screw penetration into the radiocarpal joint
. Inadequate restoration of radial inclination
. Failure to address ulnar positive variance

Correct Answer & Explanation

. Volar plate placement distal to the watershed line

Explanation

FPL attrition and spontaneous rupture is a well-recognized complication of volar locking plating for distal radius fractures. It most commonly occurs when the plate is placed too distally, crossing the "watershed line" of the distal radius, creating a mechanical prominence that directly abrades the FPL tendon (Soong Grade 2).

Question 2264

Topic: Nerve & Tendon

A 45-year-old woman presents with isolated weakness in her right hand. On examination, she is unable to form an 'OK' sign with her thumb and index finger, instead demonstrating an extended posture of the distal interphalangeal joint of the index finger and the interphalangeal joint of the thumb. She reports no sensory deficits. Entrapment of the affected nerve most commonly occurs at which of the following anatomical structures?

. Ligament of Struthers
. Arcade of Frohse
. Tendinous edge of the deep head of the pronator teres
. Cubital tunnel retinaculum
. Guyon's canal

Correct Answer & Explanation

. Tendinous edge of the deep head of the pronator teres

Explanation

The patient is presenting with Anterior Interosseous Nerve (AIN) syndrome, characterized by weakness of the flexor pollicis longus (FPL), the flexor digitorum profundus (FDP) to the index (and sometimes middle) finger, and the pronator quadratus. This results in the inability to make the 'OK' sign, leading to a pinch with extended distal joints (Kiloh-Nevin sign). Because the AIN is a purely motor branch, there is no sensory loss. The most common site of AIN entrapment is the tendinous edge of the deep head of the pronator teres (or the fibrous arcade of the FDS).

Question 2265

Topic: Wrist & Carpus

A 60-year-old woman undergoes volar locking plate fixation for a displaced, comminuted distal radius fracture. Six months postoperatively, she presents with the sudden inability to actively flex the interphalangeal joint of her thumb. She denies any new trauma. This complication is most strongly associated with which of the following intraoperative technical errors?

. Screws penetrating the dorsal cortex of the distal radius
. Placement of the volar plate distal to the watershed line
. Failure to repair the pronator quadratus during closure
. Over-distraction of the radiocarpal joint during reduction
. Use of a non-locking screw in the most ulnar distal plate hole

Correct Answer & Explanation

. Placement of the volar plate distal to the watershed line

Explanation

The patient has experienced an attritional rupture of the flexor pollicis longus (FPL) tendon. In volar plating of the distal radius, the FPL tendon is at high risk of attrition and rupture if the plate is positioned too far distally, crossing the 'watershed line' (the bony ridge marking the volar margin of the distal radius articular surface). Prominent hardware at this level directly rubs against the flexor tendons. Dorsal screw penetration causes extensor tendon ruptures (most commonly EPL).

Question 2266

Topic: Wrist & Carpus
A 40-year-old male presents with chronic wrist pain and an untreated scaphoid fracture sustained 10 years ago. Radiographs reveal osteoarthritis involving the radioscaphoid joint and the capitolunate joint, but the radiolunate joint is remarkably spared. What is the correct stage of Scaphoid Nonunion Advanced Collapse (SNAC)?
. Stage I
. Stage II
. Stage III
. Stage IV
. SLAC Stage III

Correct Answer & Explanation

. Stage II

Explanation

SNAC staging describes the predictable progression of wrist arthritis following a scaphoid nonunion. Stage I involves the radial styloid and distal scaphoid. Stage II involves the entire radioscaphoid joint. Stage III adds involvement of the capitolunate joint. Stage IV involves the entire carpus. The radiolunate joint is typically spared in both SNAC and SLAC due to the spherical congruency of that articulation.

Question 2267

Topic: 7. Hand and Wrist
A 25-year-old butcher sustains a knife laceration to the palmar aspect of his index finger at the level of the proximal phalanx, transecting both the FDS and FDP tendons. According to the Verdan classification, in which zone did this flexor tendon injury occur?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Flexor tendon Zone II, historically called 'no man's land', extends from the proximal edge of the A1 pulley (at the level of the distal palmar crease) to the insertion of the FDS tendon on the middle phalanx. Lacerations at the level of the proximal phalanx fall into this zone and frequently involve both the FDS and FDP tendons.

Question 2268

Topic: 7. Hand and Wrist

In a patient with an irreversible high radial nerve palsy, a common tendon transfer to restore wrist extension and finger extension utilizes the Pronator Teres (PT) to Extensor Carpi Radialis Brevis (ECRB) and Flexor Carpi Radialis (FCR) to Extensor Digitorum Communis (EDC). Which of the following is an absolute prerequisite for using the FCR for this transfer?

. Intact Flexor Carpi Ulnaris (FCU) function
. Intact Palmaris Longus (PL) function
. At least 30 degrees of passive wrist extension
. Functional Extensor Indicis Proprius (EIP)
. Normal median nerve sensation

Correct Answer & Explanation

. Intact Flexor Carpi Ulnaris (FCU) function

Explanation

Before transferring the FCR to restore finger extension, the surgeon must ensure the FCU is intact and functional. If the FCR is transferred and the FCU is weak or absent, the patient will lose significant active wrist flexion capability, leading to severe functional impairment.

Question 2269

Topic: 7. Hand and Wrist

A 42-year-old carpenter presents with chronic dorsal wrist pain. Radiographs demonstrate sclerosis of the lunate, normal carpal height, and negative ulnar variance. An MRI confirms avascular necrosis of the lunate without fragmentation. What is the most appropriate surgical intervention?

. Proximal row carpectomy
. Scaphocapitate fusion
. Lunate excision and silastic replacement
. Radial shortening osteotomy
. Total wrist arthrodesis

Correct Answer & Explanation

. Radial shortening osteotomy

Explanation

The patient has Lichtman Stage II Kienbock's disease (sclerosis, intact lunate anatomy, no carpal collapse) with negative ulnar variance. Joint-leveling procedures, such as a radial shortening osteotomy, are the treatment of choice. This mechanically unloads the lunate fossa, allowing for potential revascularization or halting of disease progression prior to carpal collapse.

Question 2270

Topic: 7. Hand and Wrist

Which of Kanavel's cardinal signs is generally considered the most sensitive and earliest indicator of acute pyogenic flexor tenosynovitis?

. Flexed resting posture of the digit
. Fusiform swelling of the entire digit
. Tenderness along the entire course of the flexor tendon sheath
. Severe pain elicited with passive extension of the digit
. Palmar erythema tracking towards the carpal tunnel

Correct Answer & Explanation

. Severe pain elicited with passive extension of the digit

Explanation

Kanavel's four cardinal signs of flexor tenosynovitis are: 1) Flexed resting posture of the digit, 2) Fusiform swelling (sausage digit), 3) Tenderness along the flexor tendon sheath, and 4) Severe pain with passive extension. Pain with passive extension stretches the inflamed synovium and is widely recognized as the earliest and most sensitive sign of the condition.

Question 2271

Topic: 7. Hand and Wrist

A 28-year-old carpenter lacerates his index finger with a utility knife. Surgical exploration reveals a complete laceration of both the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) within Zone II. Which of the following correctly describes the anatomical boundaries of flexor tendon Zone II?

. From the musculotendinous junction to the proximal edge of the A1 pulley
. From the proximal edge of the A1 pulley to the insertion of the FDS on the middle phalanx
. From the distal edge of the carpal tunnel to the proximal edge of the A1 pulley
. From the insertion of the FDS to the insertion of the FDP on the distal phalanx
. From the proximal carpal row to the distal edge of the A1 pulley

Correct Answer & Explanation

. From the proximal edge of the A1 pulley to the insertion of the FDS on the middle phalanx

Explanation

Flexor tendon Zone II (historically referred to as 'no man's land') extends from the proximal edge of the A1 pulley (at the level of the metacarpophalangeal joint) to the insertion of the FDS on the middle phalanx. It is characterized by the presence of both FDS and FDP tendons tightly enclosed within the same fibro-osseous sheath.

Question 2272

Topic: Nerve & Tendon

During surgical release of a severe trigger finger, a surgeon inadvertently incises the entire A2 pulley of the middle finger. What biomechanical consequence is most likely to occur as a direct result of this specific iatrogenic injury?

. Swan neck deformity
. Boutonniere deformity
. Bowstringing of the flexor tendons
. Inability to actively extend the distal interphalangeal joint
. Ulnar drift of the digits

Correct Answer & Explanation

. Bowstringing of the flexor tendons

Explanation

The A2 and A4 pulleys are the critical biomechanical pulleys in the flexor tendon sheath of the digits, holding the flexor tendons close to the phalanx. Laceration or incompetence of the A2 or A4 pulley leads to bowstringing of the flexor tendons during active flexion, decreasing mechanical efficiency (excursion) and causing flexion contractures and weakness.

Question 2273

Topic: 7. Hand and Wrist
A 30-year-old carpenter sustains a laceration to the volar aspect of his index finger at the level of the proximal phalanx. Surgical exploration confirms both the flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS) are severed. According to the Strickland/Verdan classification, which zone of flexor tendon injury is this?
. Zone I
. Zone II
. Zone III
. Zone IV
. Zone V

Correct Answer & Explanation

. Zone II

Explanation

Zone II of the flexor tendon system, historically known as 'no man's land', extends from the proximal aspect of the A1 pulley (distal palmar crease) to the insertion of the FDS on the middle phalanx. Injuries here are notoriously difficult to treat due to the complex interaction between the FDS, FDP, and the fibro-osseous sheath.

Question 2274

Topic: 7. Hand and Wrist

In a patient undergoing a dorsal approach to the wrist for a distal radius fracture, Lister's tubercle serves as a key anatomical landmark. Which extensor compartment lies immediately ulnar to Lister's tubercle?

. First
. Second
. Third
. Fourth
. Fifth

Correct Answer & Explanation

. Third

Explanation

The extensor pollicis longus (EPL) tendon is housed in the third extensor compartment, which runs immediately ulnar to Lister's tubercle before crossing over the second extensor compartment tendons (ECRL and ECRB) to insert on the thumb.

Question 2275

Topic: 7. Hand and Wrist
A 32-year-old male manual laborer presents with progressive dorsal wrist pain. Radiographs reveal sclerosis and fragmentation of the lunate with a radioscaphoid angle of 70 degrees and proximal migration of the capitate. According to the Lichtman classification for Kienböck's disease, what is the correct stage and most appropriate surgical management option?
. Stage II; radial shortening osteotomy.
. Stage IIIA; radial shortening osteotomy.
. Stage IIIB; scaphocapitate fusion or proximal row carpectomy.
. Stage IV; total wrist arthrodesis.
. Stage I; temporary immobilization and NSAIDs.

Correct Answer & Explanation

. Stage IIIB; scaphocapitate fusion or proximal row carpectomy.

Explanation

The patient has Stage IIIB Kienböck's disease. Stage III indicates lunate collapse. It is divided into IIIA (normal carpal alignment) and IIIB (fixed carpal instability, indicated by a radioscaphoid angle >60 degrees or proximal capitate migration). Stage IV involves pancarpal arthritis. Joint-leveling procedures (radial shortening) are typically used for Stages I to IIIA. For Stage IIIB, salvage procedures like proximal row carpectomy or limited intercarpal fusions (STT or scaphocapitate) are indicated.

Question 2276

Topic: 7. Hand and Wrist

A 45-year-old female assembly line worker presents with severe, chronic Carpal Tunnel Syndrome. During an open carpal tunnel release, the surgeon observes a muscle belly being drawn proximally into the carpal tunnel during forceful finger flexion. Which of the following anatomic anomalies or dynamic processes best explains this operative finding?

. Anomalous palmaris longus
. Proximal migration of the abductor pollicis brevis
. Lumbrical muscle incursion
. Hypertrophied flexor digitorum superficialis to the index finger
. Aberrant flexor carpi radialis brevis

Correct Answer & Explanation

. Lumbrical muscle incursion

Explanation

Lumbrical incursion occurs when the lumbrical muscles, which originate from the flexor digitorum profundus (FDP) tendons in the palm, are drawn proximally into the carpal tunnel during forceful, simultaneous finger flexion. This dynamic process can transiently increase pressure within the carpal tunnel and is a well-recognized contributing factor in work-related carpal tunnel syndrome.

Question 2277

Topic: 7. Hand and Wrist

When performing a primary flexor tendon repair in Zone II of the hand, biomechanical studies demonstrate that the ultimate tensile strength of the repair is most directly proportional to which of the following variables?

. The caliber (thickness) of the suture material used for the epitendinous repair
. The number of core suture strands crossing the repair site
. The use of a dynamic extension splint postoperatively
. The administration of local corticosteroids to prevent adhesions
. The excision of the A2 and A4 pulleys to reduce friction

Correct Answer & Explanation

. The number of core suture strands crossing the repair site

Explanation

The ultimate tensile strength of a flexor tendon repair is directly proportional to the number of core suture strands crossing the repair site. For example, a 4-strand or 6-strand repair is significantly stronger than a 2-strand repair and is required to withstand the forces of modern early active mobilization protocols. An epitendinous suture adds approximately 10-20% strength and smooths the repair, but the core strands are the primary determinant of load to failure.

Question 2278

Topic: 7. Hand and Wrist
A 35-year-old laborer with ulnar minus variance presents with wrist pain. Radiographs reveal sclerosis, fragmentation, and early collapse of the lunate. However, the overall carpal height is maintained and the scaphoid is normally aligned. Which Lichtman stage does this represent, and what is the preferred initial surgical management?
. Stage II; Lunate excision and capitate shortening
. Stage IIIA; Joint leveling procedure (e.g., radial shortening osteotomy)
. Stage IIIB; Proximal row carpectomy
. Stage IV; Total wrist arthrodesis
. Stage I; Prolonged immobilization

Correct Answer & Explanation

. Stage IIIA; Joint leveling procedure (e.g., radial shortening osteotomy)

Explanation

This patient has Kienböck's disease. Lichtman Stage IIIA is defined by lunate sclerosis, fragmentation, and collapse, but without fixed scaphoid rotation or carpal collapse (normal carpal height). Stage IIIB involves carpal collapse (scaphoid rotary subluxation). For Stage IIIA in a patient with ulnar minus variance, a joint leveling procedure (such as radial shortening osteotomy) is the treatment of choice to offload the lunate. Stage IIIB often requires salvage procedures like PRC or STT fusion.

Question 2279

Topic: 7. Hand and Wrist

A 42-year-old carpenter presents with a 3-month history of aching pain in his proximal volar forearm and numbness involving the palmar aspect of his thumb, index, and middle fingers, as well as the thenar eminence. He has weakness in thumb opposition. A Tinel's sign is positive over the proximal anterior forearm but negative at the wrist. What is the most likely diagnosis?

. Carpal tunnel syndrome
. Anterior interosseous nerve syndrome
. Pronator syndrome
. Cubital tunnel syndrome
. C6 cervical radiculopathy

Correct Answer & Explanation

. Pronator syndrome

Explanation

The patient has Pronator syndrome, which is compression of the median nerve in the proximal forearm (most commonly between the two heads of the pronator teres). It is differentiated from carpal tunnel syndrome (CTS) by the presence of sensory loss over the thenar eminence (supplied by the palmar cutaneous branch, which branches proximal to the carpal tunnel) and an aching pain in the proximal forearm with a positive proximal Tinel's sign.

Question 2280

Topic: 7. Hand and Wrist
In Kienböck's disease, the Lichtman classification is used to guide surgical decision-making. Which of the following radiographic findings definitively differentiates Stage IIIB from Stage IIIA?
. Sclerosis of the lunate without collapse
. Fragmentation of the lunate
. Fixed scaphoid rotatory subluxation (scapholunate angle > 60 degrees)
. Osteoarthritis isolated to the midcarpal joint
. Ulnar positive variance > 2 mm

Correct Answer & Explanation

. Fixed scaphoid rotatory subluxation (scapholunate angle > 60 degrees)

Explanation

The Lichtman classification for Kienböck's disease stages the progression of lunate avascular necrosis. Stage IIIA exhibits lunate collapse but normal carpal alignment. Stage IIIB is distinguished by lunate collapse accompanied by fixed carpal instability, characteristically manifesting as fixed scaphoid rotatory subluxation (scaphoid ring sign, radioscaphoid angle > 60 degrees, or scapholunate angle > 60 degrees). Stage IV involves pancarpal arthritis.

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