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7. Hand and Wrist MCQs

Practice Set 109 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 2161

Topic: Nerve & Tendon

A paediatric orthopaedic viva scenario involves a 6-year-old boy with a heavily displaced, extension-type supracondylar fracture of the humerus. On examination, he is unable to flex the interphalangeal joint of his thumb and the distal interphalangeal joint of his index finger. Which specific nerve branch is injured, and what is the typical prognosis?

. Ulnar nerve; requires immediate open exploration.
. Posterior interosseous nerve; expected to recover spontaneously within 3 months.
. Anterior interosseous nerve; expected to recover spontaneously within 3 to 6 months.
. Recurrent motor branch of the median nerve; high risk of permanent thenar atrophy.
. Musculocutaneous nerve; requires early nerve grafting if no recovery by 6 weeks.

Correct Answer & Explanation

. Anterior interosseous nerve; expected to recover spontaneously within 3 to 6 months.

Explanation

The anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar fractures. It presents with the inability to make an "OK" sign, and the vast majority resolve spontaneously within 3 to 6 months without surgical exploration.

Question 2162

Topic: 7. Hand and Wrist

A patient with carpal tunnel syndrome reports that her symptoms are severely exacerbated when she tightly grips tools for prolonged periods. This is attributed to 'lumbrical incursion'. In what finger position do the lumbrical muscles travel furthest proximally into the carpal tunnel?

. Full composite extension of the digits
. Metacarpophalangeal joint flexion with interphalangeal joint extension
. Full composite flexion of the digits
. Isolated distal interphalangeal joint flexion
. Radial deviation with thumb opposition

Correct Answer & Explanation

. Full composite flexion of the digits

Explanation

Lumbrical incursion occurs when the lumbrical muscle bellies slide proximally into the carpal tunnel, increasing intracarpal pressure and compressing the median nerve. This proximal excursion is maximal during full composite flexion of the digits (making a tight fist). This phenomenon explains why tasks requiring prolonged or repetitive tight gripping can significantly exacerbate carpal tunnel syndrome symptoms.

Question 2163

Topic: Wrist & Carpus

A 65-year-old female sustains a nondisplaced distal radius fracture and is treated non-operatively in a short arm cast. Six weeks later, she presents with an inability to actively extend her thumb interphalangeal joint. What is the most widely accepted mechanism for this specific complication following a nondisplaced distal radius fracture?

. Sharp mechanical attrition of the tendon against a displaced dorsal cortical fragment
. Ischemic necrosis of the tendon secondary to hematoma and increased pressure within the intact third extensor compartment
. Direct injury to the posterior interosseous nerve during the initial trauma
. Iatrogenic tethering of the tendon by a poorly molded cast
. Avulsion of the extensor pollicis longus muscle belly at the musculotendinous junction

Correct Answer & Explanation

. Ischemic necrosis of the tendon secondary to hematoma and increased pressure within the intact third extensor compartment

Explanation

The patient has experienced an Extensor Pollicis Longus (EPL) tendon rupture. In the setting of a non-displaced or minimally displaced distal radius fracture treated non-operatively, the prevailing theory for EPL rupture is vascular watershed ischemia. The intact extensor retinaculum confines the third dorsal compartment. Bleeding and edema from the fracture increase compartment pressure, compressing the precarious vascular supply to the EPL as it wraps around Lister's tubercle, leading to focal ischemic necrosis and delayed rupture (often around 4-8 weeks). Mechanical attrition is the usual cause after volar plating with prominent dorsal screws.

Question 2164

Topic: Hand Trauma & Infection

A 35-year-old skier presents with pain and weakness in the right thumb after a fall. Examination demonstrates significant laxity of the ulnar collateral ligament (UCL) of the metacarpophalangeal joint. An MRI reveals a 'Stener lesion.' What is the exact anatomical arrangement that defines a Stener lesion?

. The torn proximal stump of the UCL is displaced superficial to the adductor pollicis aponeurosis.
. The torn distal stump of the UCL is trapped deep to the abductor pollicis brevis tendon.
. The UCL is avulsed with a bony fragment that is trapped within the joint space.
. The torn proximal stump of the UCL is displaced deep to the extensor pollicis longus tendon.
. The torn distal stump of the UCL is displaced superficial to the flexor pollicis longus tendon.

Correct Answer & Explanation

. The torn proximal stump of the UCL is displaced superficial to the adductor pollicis aponeurosis.

Explanation

A Stener lesion occurs when the ulnar collateral ligament (UCL) of the thumb MCP joint tears (usually distal avulsion) and the torn proximal stump displaces superficially and becomes trapped outside of the adductor aponeurosis. Because the aponeurosis is interposed between the torn ends, conservative management fails and surgical repair is required.

Question 2165

Topic: 7. Hand and Wrist
A 22-year-old professional rugby player sustains a closed hyperextension injury to his right ring finger while grabbing an opponent's jersey. He is unable to actively flex the distal interphalangeal (DIP) joint. Radiographs show a small bony fragment at the level of the A4 pulley. Surgical exploration reveals that the flexor digitorum profundus (FDP) tendon has avulsed from the bony fragment and retracted into the palm. Which Leddy and Packer classification type does this injury represent?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type IV

Explanation

The Leddy and Packer classification describes FDP avulsion injuries (Jersey finger). Type I involves retraction into the palm (disrupting all vincula, requires repair within 7-10 days). Type II retracts to the PIP joint (held by intact vincula). Type III involves a large bony avulsion that catches at the A4 pulley, preventing further retraction. Type IV is a double avulsion, where the tendon avulses from the bony fragment; the bony fragment remains at the A4 pulley, but the tendon retracts into the palm. Type V involves a bony avulsion with an intra-articular fracture of the distal phalanx.

Question 2166

Topic: 7. Hand and Wrist

A 45-year-old woman falls on her outstretched hand and sustains a volar Barton's fracture (a displaced intra-articular fracture of the distal radius with volar subluxation of the carpus). The volar marginal fragment typically remains attached to the carpus due to the intact volar radiocarpal ligaments. Which specific ligaments are primarily responsible for this continued attachment?

. Dorsal radiocarpal and dorsal intercarpal ligaments
. Scapholunate interosseous and lunotriquetral ligaments
. Short radiolunate and long radiolunate ligaments
. Radial collateral and ulnar collateral ligaments
. Palmar aponeurosis and transverse carpal ligament

Correct Answer & Explanation

. Short radiolunate and long radiolunate ligaments

Explanation

A volar Barton's fracture involves a volar shear fragment of the distal radius. The carpus displaces volarly with this fracture fragment because of the strong, intact volar radiocarpal ligaments—specifically the short radiolunate and long radiolunate ligaments, which originate from the volar lip of the distal radius. Reduction and stabilization of this bony fragment via a volar buttress plate inherently reduces the carpus back to its anatomic position.

Question 2167

Topic: 7. Hand and Wrist

A 22-year-old male falls on an outstretched hand and sustains a displaced fracture through the waist of the scaphoid. He is at high risk for developing avascular necrosis of the proximal pole. This risk is primarily due to the retrograde intraosseous blood supply of the scaphoid, which is derived mainly from which vessel?

. Volar carpal branch of the radial artery
. Dorsal carpal branch of the radial artery
. Superficial palmar arch
. Anterior interosseous artery
. Ulnar artery

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The scaphoid receives 70-80% of its blood supply from branches of the radial artery, specifically via the dorsal carpal branch. These vessels enter the scaphoid distally and flow in a retrograde direction to supply the proximal pole. Thus, waist or proximal fractures interrupt this supply, leading to avascular necrosis.

Question 2168

Topic: 7. Hand and Wrist

A 52-year-old male presents with advanced Scapholunate Advanced Collapse (SLAC) wrist following an untreated scapholunate ligament dissociation. As the predictable pattern of progressive articular degeneration occurs, which of the following joints is classically spared?

. Radioscaphoid joint
. Capitolunate joint
. Scaphotrapeziotrapezoid (STT) joint
. Radiolunate joint
. Capitate-hamate joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In SLAC wrist, the radiolunate joint is characteristically spared from degenerative changes. This is because the lunate and the lunate fossa of the radius possess a concentrically spherical articulation that is maintained even when the lunate falls into a DISI deformity. The degeneration predictably occurs at the radial styloid, then the entire radioscaphoid joint, and finally the capitolunate joint.

Question 2169

Topic: Nerve & Tendon

A 35-year-old female presents with an inability to make an 'OK' sign with her thumb and index finger, demonstrating flattening of the distal interphalangeal joint of the index finger and interphalangeal joint of the thumb. She has no sensory deficits. Which nerve is compressed, and what is the most common anatomic site of entrapment?

. Ulnar nerve at Guyon's canal
. Median nerve at the carpal tunnel
. Anterior interosseous nerve at the pronator teres or FDS arcade
. Posterior interosseous nerve at the arcade of Frohse
. Radial nerve at the spiral groove

Correct Answer & Explanation

. Anterior interosseous nerve at the pronator teres or FDS arcade

Explanation

The patient has Anterior Interosseous Nerve (AIN) syndrome, evidenced by weakness in the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) to the index finger. The AIN is a purely motor branch of the median nerve. Compression most commonly occurs at the deep head of the pronator teres or the fibrous arcade of the flexor digitorum superficialis (FDS).

Question 2170

Topic: Nerve & Tendon

A 6-year-old boy falls from monkey bars and sustains a widely displaced, extension-type supracondylar humerus fracture. After closed reduction and percutaneous pinning, the patient demonstrates an inability to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is injured?

. Main trunk of the median nerve
. Anterior interosseous nerve
. Radial nerve
. Ulnar nerve
. Posterior interosseous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The Anterior Interosseous Nerve (AIN) is the most frequently injured nerve in extension-type supracondylar humerus fractures (often contused by the proximal fragment). It innervates the flexor pollicis longus (FPL) and flexor digitorum profundus (FDP) to the index and long fingers. The radial nerve is the second most common, particularly in posteromedial displacement.

Question 2171

Topic: Hand Trauma & Infection

A 40-year-old carpenter sustains a puncture wound to the volar aspect of his index finger and presents 48 hours later with severe throbbing pain. Which of the following is NOT one of Kanavel's cardinal signs of acute flexor tenosynovitis?

. Fusiform (sausage-like) swelling of the entire digit
. Resting posture of the digit in slight flexion
. Severe pain with passive extension of the digit
. Localized tenderness along the entire course of the flexor tendon sheath
. Pitting edema over the dorsal aspect of the hand

Correct Answer & Explanation

. Pitting edema over the dorsal aspect of the hand

Explanation

Kanavel's four cardinal signs of flexor tenosynovitis are: 1) fusiform swelling of the digit, 2) resting flexed posture, 3) tenderness along the flexor tendon sheath, and 4) disproportionate pain with passive extension. While dorsal pitting edema can occur in hand infections due to the loose dorsal skin and venous/lymphatic drainage, it is not one of the cardinal signs.

Question 2172

Topic: 7. Hand and Wrist

A 65-year-old female sustains a distal radius fracture treated with closed reduction and casting. Four weeks later, she complains of severe burning pain in the hand. On exam, the hand is swollen, erythematous, profoundly stiff, and demonstrates abnormal sweating and allodynia. What is the most likely diagnosis?

. Acute compartment syndrome of the forearm
. Complex Regional Pain Syndrome (CRPS) Type I
. Complex Regional Pain Syndrome (CRPS) Type II
. Rupture of the Extensor Pollicis Longus (EPL) tendon
. Median nerve entrapment in the carpal tunnel

Correct Answer & Explanation

. Complex Regional Pain Syndrome (CRPS) Type I

Explanation

The clinical picture of burning pain out of proportion, sudomotor/vasomotor changes, allodynia, and stiffness following trauma (like a distal radius fracture) is classic for Complex Regional Pain Syndrome (CRPS). It is classified as Type I (formerly Reflex Sympathetic Dystrophy) when there is no definable major nerve injury. Type II (formerly Causalgia) requires a distinct, identified nerve injury.

Question 2173

Topic: 7. Hand and Wrist

A rock climber feels a pop in his ring finger while pulling on a crimp hold. He presents with pain and bowstringing of the flexor tendons on resisted flexion. Disruption of which pair of pulleys will result in the most significant bowstringing and loss of mechanical advantage?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 (located over the proximal phalanx) and A4 (located over the middle phalanx) pulleys are the crucial biomechanical pulleys in the flexor tendon system. Loss of both leads to significant bowstringing, reduced active range of motion, and loss of mechanical efficiency.

Question 2174

Topic: 7. Hand and Wrist

A 40-year-old female presents with persistent pain in the proximal volar forearm and weakness in the thumb and index finger. She is unable to make an 'OK' sign, instead demonstrating a flat pinch. Sensation in the hand is completely normal. Which of the following structures is most likely compressing the affected nerve?

. Ligament of Struthers
. Bicipital aponeurosis (lacertus fibrosus)
. Tendinous edge of the deep head of the pronator teres
. Arcade of Frohse
. Osborne's ligament

Correct Answer & Explanation

. Tendinous edge of the deep head of the pronator teres

Explanation

The presentation is classic for Anterior Interosseous Nerve (AIN) syndrome, characterized by motor weakness of the FPL, FDP to the index finger, and pronator quadratus, with no sensory deficit. The most common site of AIN compression is the tendinous edge of the deep head of the pronator teres.

Question 2175

Topic: Nerve & Tendon

A 30-year-old male sustains a complete laceration of the median nerve at the wrist joint level. Despite the complete transection, physical examination reveals partially preserved function of the thenar musculature. This clinical finding is most likely explained by the presence of which of the following anomalous neural interconnections?

. Martin-Gruber anastomosis
. Riche-Cannieu anastomosis
. Marinacci communication
. Berrettini anastomosis
. Bouvier's anomaly

Correct Answer & Explanation

. Riche-Cannieu anastomosis

Explanation

The Riche-Cannieu anastomosis is an anomalous connection between the deep motor branch of the ulnar nerve and the recurrent motor branch of the median nerve in the palm. When present, it allows the ulnar nerve to supply innervation to some or all of the thenar muscles, preserving function even if the median nerve is lacerated at the wrist. Martin-Gruber is in the forearm.

Question 2176

Topic: Wrist & Carpus
A 45-year-old manual laborer presents with chronic wrist pain and a known scaphoid nonunion. Radiographs demonstrate arthritis at the radioscaphoid and capitolunate joints, with preservation of the radiolunate joint. What is the SNAC stage and most appropriate definitive surgical treatment?
. SNAC I; Radial styloidectomy
. SNAC II; Proximal row carpectomy (PRC)
. SNAC III; Four-corner fusion with scaphoid excision
. SNAC III; Proximal row carpectomy (PRC)
. SNAC IV; Total wrist arthrodesis

Correct Answer & Explanation

. SNAC III; Four-corner fusion with scaphoid excision

Explanation

Scaphoid Nonunion Advanced Collapse (SNAC) is staged by the progression of arthritis. Stage I involves the radial styloid; Stage II involves the entire radioscaphoid joint; Stage III involves the capitolunate joint; Stage IV involves the entire carpus (including radiolunate). This patient is SNAC III. Proximal row carpectomy (PRC) is contraindicated in SNAC III because the capitate head is arthritic and would articulate with the lunate fossa. Therefore, four-corner fusion with scaphoid excision is the treatment of choice.

Question 2177

Topic: 7. Hand and Wrist

In Dupuytren's disease, the spiral cord is responsible for proximal interphalangeal (PIP) joint contracture. As it contracts, it characteristically displaces the digital neurovascular bundle in which direction?

. Dorsal to the cord
. Central, superficial, and proximal
. Lateral and deep
. Unchanged from its anatomical position
. Volar, lateral, and distal

Correct Answer & Explanation

. Volar, lateral, and distal

Explanation

The spiral cord in Dupuytren's contracture is formed by the pretendinous band, spiral band, lateral digital sheet, and Grayson's ligament. As this cord shortens and thickens, it predictably pulls the neurovascular bundle centrally (towards the midline of the digit), superficially (volar), and proximally. This abnormal anatomy places the nerve at exceptionally high risk of iatrogenic injury during fasciectomy.

Question 2178

Topic: Nerve & Tendon

A cyclist complains of isolated weakness in the interosseous muscles of the hand and a claw deformity of the ring and small fingers. He has completely normal sensation in the small finger and the ulnar half of the ring finger. Compression of the ulnar nerve is most likely occurring in which zone of Guyon's canal?

. Zone 1
. Zone 2
. Zone 3
. Cubital tunnel
. Arcade of Struthers

Correct Answer & Explanation

. Zone 2

Explanation

Guyon's canal is divided into 3 zones. Zone 1 is proximal to the nerve bifurcation; compression here causes mixed motor and sensory deficits. Zone 2 surrounds the deep motor branch; compression here causes isolated motor deficits (interosseous weakness, clawing) with spared sensation. Zone 3 surrounds the superficial sensory branch; compression causes isolated sensory deficits.

Question 2179

Topic: 7. Hand and Wrist

In the natural history of a scaphoid nonunion advanced collapse (SNAC) pattern of the wrist, which of the following articulations is classically the LAST to develop degenerative changes?

. Radioscaphoid joint
. Capitolunate joint
. Radiolunate joint
. Scaphocapitate joint
. Scaphotrapezial joint

Correct Answer & Explanation

. Radiolunate joint

Explanation

In a SNAC wrist, the sequence of arthritic changes predictably begins between the distal scaphoid fragment and the radial styloid (Stage 1). It then progresses to the scaphocapitate joint (Stage 2) and the capitolunate joint (Stage 3). The radiolunate joint is classically spared and is the last to degenerate because the lunate maintains a concentric, congruent relationship with the spherical lunate fossa of the radius.

Question 2180

Topic: Wrist & Carpus
A 35-year-old male laborer presents with chronic right wrist pain. Radiographs demonstrate a scaphoid nonunion with marked sclerosis, joint space narrowing at the radioscaphoid joint, and arthritic changes at the capitolunate joint. The radiolunate joint space is completely preserved. According to the Scaphoid Nonunion Advanced Collapse (SNAC) staging system, what is the correct stage of this patient's wrist?
. SNAC Stage I
. SNAC Stage II
. SNAC Stage III
. SLAC Stage II
. SLAC Stage III

Correct Answer & Explanation

. SNAC Stage III

Explanation

SNAC staging is progressive: Stage I involves arthrosis isolated to the radial styloid-scaphoid articulation. Stage II extends to involve the scaphocapitate joint. Stage III involves the capitolunate joint, leading to periscaphoid arthrosis. The radiolunate joint is characteristically spared in SNAC (and SLAC) wrists because the radiolunate ligament provides a concentric matching surface that resists shear forces.

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