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7. Hand and Wrist MCQs

Practice Set 264 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 5261

Topic: Nerve & Tendon

A 6-year-old boy falls from the monkey bars and sustains a widely displaced extension-type supracondylar humerus fracture. On examination, he is unable to flex the interphalangeal joint of his thumb and the distal interphalangeal joint of his index finger. Which nerve is most likely injured?

. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve
. Posterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

Correct Answer: C (Anterior interosseous nerve)The anterior interosseous nerve (AIN), a motor branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. It innervates the flexor pollicis longus (FPL), the flexor digitorum profundus (FDP) to the index and middle fingers, and the pronator quadratus. Injury results in an inability to make an "OK" sign, as the patient cannot actively flex the IP joint of the thumb and the DIP joint of the index finger.

Question 5262

Topic: Nerve & Tendon

A 6-year-old girl falls from monkey bars and sustains a widely displaced extension-type supracondylar humerus fracture. On examination, she is unable to flex the interphalangeal joint of her thumb and the distal interphalangeal joint of her index finger. Which nerve branch is most likely injured?

. Posterior interosseous nerve
. Anterior interosseous nerve
. Ulnar nerve
. Recurrent motor branch of the median nerve
. Superficial radial nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

Correct Answer: BThe anterior interosseous nerve (AIN), a motor branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. AIN palsy presents with the inability to flex the interphalangeal (IP) joint of the thumb (innervating the flexor pollicis longus) and the distal interphalangeal (DIP) joint of the index finger (innervating the flexor digitorum profundus to the index and middle fingers). This leads to an abnormal "A-OK" sign, where the patient pinches with the pulps of the fingers rather than the tips. The median nerve overall is the most frequently injured nerve in these fractures, specifically its AIN branch.

Question 5263

Topic: 7. Hand and Wrist

A 45-year-old female administrative assistant presents with numbness and tingling in her radial three-and-a-half digits, which frequently awakens her at night. She is diagnosed with carpal tunnel syndrome and elects to undergo surgical release. During the procedure, the transverse carpal ligament is divided. Which of the following structures forms the ulnar border of the carpal tunnel?

. Scaphoid tubercle and trapezium
. Hook of the hamate and pisiform
. Lunate and triquetrum
. Capitate and trapezoid
. Styloid process of the ulna

Correct Answer & Explanation

. Hook of the hamate and pisiform

Explanation

Correct Answer: Hook of the hamate and pisiformThe carpal tunnel is a fibro-osseous canal in the wrist. The roof is formed by the transverse carpal ligament (flexor retinaculum). The floor is formed by the proximal and distal rows of carpal bones. The ulnar border is defined by the hook of the hamate and the pisiform. The radial border is defined by the scaphoid tubercle and the crest of the trapezium. The tunnel contains 10 structures: the median nerve, four flexor digitorum superficialis (FDS) tendons, four flexor digitorum profundus (FDP) tendons, and the flexor pollicis longus (FPL) tendon.

Question 5264

Topic: Wrist & Carpus

A 55-year-old female undergoes open reduction and internal fixation of a distal radius fracture using a volar locking plate. Six months postoperatively, she presents with an inability to actively flex the interphalangeal joint of her thumb. Radiographs reveal the plate is positioned distally, over the watershed line. Which tendon is most likely ruptured?

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

Correct Answer & Explanation

. Flexor pollicis longus (FPL)

Explanation

Placement of a volar plate at or distal to the watershed line of the distal radius causes prominence of the hardware in the flexor compartment. This friction most commonly leads to attrition and subsequent rupture of the flexor pollicis longus (FPL) tendon.

Question 5265

Topic: 7. Hand and Wrist
A 45-year-old manual laborer presents with chronic, debilitating wrist pain. Radiographs reveal a scaphoid nonunion with advanced collapse (SNAC Stage III), demonstrating arthritis at the radioscaphoid and midcarpal joints, while the radiolunate joint is spared. What is the most appropriate surgical treatment?
. Proximal row carpectomy
. Four-corner arthrodesis with scaphoid excision
. Radial styloidectomy
. Scaphoid open reduction internal fixation with vascularized bone grafting
. Total wrist arthroplasty

Correct Answer & Explanation

. Four-corner arthrodesis with scaphoid excision

Explanation

In SNAC Stage III, arthritic changes involve both the radioscaphoid and midcarpal (scaphocapitate and lunocapitate) joints. Four-corner fusion with scaphoid excision is the preferred treatment, as a proximal row carpectomy is contraindicated when capitate arthritis is present.

Question 5266

Topic: 7. Hand and Wrist

A 32-year-old carpenter sustains a deep volar laceration to his right index finger at the level of the proximal phalanx (Zone II). Surgical exploration reveals complete sharp transection of both the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) tendons. What is the current gold standard surgical management for this specific injury pattern?

. Primary repair of the FDP tendon only and excision of the FDS tendon slips.
. Primary repair of both the FDS and FDP tendons using a multistrand core suture and epitendinous repair.
. Immediate tendon grafting of the FDP and excision of the FDS.
. Two-stage tendon reconstruction utilizing a silicone Hunter rod.
. Primary repair of the FDS tendon only with tenodesis of the FDP to the middle phalanx.

Correct Answer & Explanation

. Primary repair of both the FDS and FDP tendons using a multistrand core suture and epitendinous repair.

Explanation

The optimal management for Zone II flexor tendon lacerations is primary repair of both the FDS and FDP tendons. Repairing both tendons helps preserve the vincula blood supply, reduces the risk of PIP joint hyperextension (bowstringing), and provides superior gliding mechanics compared to isolated FDP repair.

Question 5267

Topic: 7. Hand and Wrist

A patient with right hip osteoarthritis uses a cane in the left hand. By what primary biomechanical mechanism does this relieve pain in the right hip?

. It shifts the center of gravity laterally towards the affected hip
. It provides a counter-moment that decreases the required right hip abductor force
. It directly increases the lever arm of the right hip abductors
. It eliminates the lever arm of the body weight

Correct Answer & Explanation

. It provides a counter-moment that decreases the required right hip abductor force

Explanation

Using a cane in the contralateral hand produces an upward force with a long lever arm from the affected hip. This generates a powerful counter-moment, significantly reducing the required abductor muscle force and the resultant joint reaction force.

Question 5268

Topic: 7. Hand and Wrist

A 65-year-old man with severe right hip osteoarthritis is advised to use a cane to offload the affected joint. Which of the following biomechanical descriptions accurately explains the primary benefit of proper cane usage?

. Held in the right hand, it shifts the center of gravity laterally, increasing the body weight moment arm.
. Held in the right hand, it decreases the joint reaction force by directly supporting body weight on the affected side.
. Held in the left hand, it provides an upward ground reaction force at a long distance, significantly reducing the required abductor muscle force.
. Held in the left hand, it decreases the abductor moment arm and increases pelvic drop.
. Held in either hand, it primarily acts to increase the joint reaction force to stimulate bone remodeling.

Correct Answer & Explanation

. Held in the left hand, it provides an upward ground reaction force at a long distance, significantly reducing the required abductor muscle force.

Explanation

A cane should be held in the contralateral hand. It creates a large counter-moment that assists the hip abductors, drastically reducing the abductor force required to keep the pelvis level, thereby decreasing the total hip joint reaction force.

Question 5269

Topic: 7. Hand and Wrist

A patient with advanced right hip osteoarthritis is advised to use a cane. In which hand should the cane be held, and what is the primary biomechanical rationale?

. Right hand; decreases the abductor muscle force required.
. Left hand; decreases the abductor muscle force required.
. Right hand; increases the body weight moment arm.
. Left hand; increases the resultant joint reaction force.
. Left hand; shifts the center of gravity to the right.

Correct Answer & Explanation

. Left hand; decreases the abductor muscle force required.

Explanation

A cane should be held in the contralateral (left) hand. It exerts an upward force that creates a moment opposing body weight, significantly decreasing the required abductor muscle force and resultant joint reaction force.

Question 5270

Topic: 7. Hand and Wrist

When utilizing the Green-Anderson growth remaining charts for predicting limb length discrepancy, which variable is most critical for accurate assessment?

. Chronological age.
. Bone age.
. Tanner staging.
. Current height percentiles.
. Patient weight.

Correct Answer & Explanation

. Bone age.

Explanation

The Green-Anderson growth remaining charts strictly rely on skeletal bone age (typically determined via left hand and wrist radiographs) rather than chronological age to accurately predict remaining growth of the lower extremities.

Question 5271

Topic: 7. Hand and Wrist

A 65-year-old male with symptomatic severe right hip osteoarthritis is instructed to use a cane for ambulation. To maximally decrease the joint reaction force on the right hip, in which hand should the cane be held and what is the biomechanical rationale?

. Right hand; it decreases the body weight moment arm.
. Right hand; it increases the abductor moment arm.
. Left hand; the cane's ground reaction force creates a moment that assists the right abductors.
. Left hand; it shifts the center of mass laterally over the right hip.
. Either hand; the cane strictly unloads vertical body weight independent of moments.

Correct Answer & Explanation

. Left hand; the cane's ground reaction force creates a moment that assists the right abductors.

Explanation

The cane should be held in the contralateral (left) hand. The upward ground reaction force through the cane produces a torque on the pelvis that acts in the same direction as the affected hip's abductor muscles, drastically reducing their required force and the resulting joint reaction force.

Question 5272

Topic: 7. Hand and Wrist

A patient with severe right hip osteoarthritis uses a cane in the left hand. What is the primary biomechanical mechanism by which this reduces the right hip joint reaction force (JRF)?

. It shifts the body's center of gravity towards the left, increasing the body weight moment arm.
. The cane provides a floor reaction force on a long moment arm, significantly reducing the required abductor muscle force.
. It directly elevates the pelvis on the swing side, reducing the hip abductor moment arm.
. It medializes the right hip center of rotation.
. It increases the tension in the iliotibial band, unloading the medial compartment.

Correct Answer & Explanation

. The cane provides a floor reaction force on a long moment arm, significantly reducing the required abductor muscle force.

Explanation

Using a cane in the contralateral hand provides an upward floor reaction force at a long distance from the hip center, counteracting the body weight moment. This significantly reduces the force required by the abductor muscles, thereby decreasing the overall hip JRF.

Question 5273

Topic: 7. Hand and Wrist

A patient with right hip osteoarthritis is advised to use a cane for ambulation. In which hand should the cane be held, and what is the primary biomechanical rationale for this intervention to decrease the hip joint reaction force?

. Right hand to decrease the body weight moment arm
. Right hand to increase the abductor moment arm
. Left hand to provide an upward counter-torque that reduces the required abductor force
. Left hand to shift the center of gravity laterally over the right hip
. Left hand to increase the moment arm of the abductors

Correct Answer & Explanation

. Left hand to provide an upward counter-torque that reduces the required abductor force

Explanation

Using a cane in the contralateral hand reduces the hip joint reaction force by creating an upward ground reaction force with a long moment arm. This counter-torque significantly decreases the force required by the ipsilateral hip abductors to maintain a level pelvis during the single-leg stance phase.

Question 5274

Topic: 7. Hand and Wrist

A patient with right hip osteoarthritis is advised to use a cane in their left hand during ambulation. What is the primary biomechanical mechanism by which this intervention reduces the joint reaction force (JRF) across the right hip?

. Decreases the body weight lever arm
. Increases the abductor lever arm
. Decreases the required abductor muscle force
. Shifts the center of gravity laterally over the right hip
. Increases the ground reaction force on the right leg

Correct Answer & Explanation

. Decreases the required abductor muscle force

Explanation

Using a cane in the contralateral hand provides an upward force at a long distance from the hip, creating a moment that assists the abductor muscles. This significantly decreases the force required from the abductors to maintain a level pelvis, thereby proportionally reducing the JRF.

Question 5275

Topic: 7. Hand and Wrist

A 10-year-old child presents with sparse hair, a pear-shaped nose, and short stature. A hand radiograph is obtained.

What is the most characteristic radiographic finding associated with this syndrome?

. Delta phalanx
. Cone-shaped epiphyses
. Acro-osteolysis
. Erlenmeyer flask deformity
. Madelung deformity

Correct Answer & Explanation

. Cone-shaped epiphyses

Explanation

Trichorhinophalangeal syndrome (TRPS) Type 1 is characterized by cone-shaped epiphyses of the phalanges. These most commonly affect the middle phalanges, leading to clinical clinodactyly.

Question 5276

Topic: 7. Hand and Wrist

A 12-year-old girl is evaluated for short stature, a pear-shaped nose, and sparse hair. She has brachydactyly and bilateral hip pain. Radiographs of her hands are shown.

What is the hallmark radiographic finding in the hands associated with this syndrome?

. Epiphyseal stippling of the phalanges
. Acro-osteolysis of the distal tufts
. Erlenmeyer flask deformities of the metacarpals
. Cone-shaped epiphyses of the phalanges
. Subperiosteal bone resorption

Correct Answer & Explanation

. Cone-shaped epiphyses of the phalanges

Explanation

Trichorhinophalangeal syndrome type 1 (TRPS1) typically presents with sparse hair, bulbous nose, and cone-shaped epiphyses in the phalanges. This leads to brachydactyly and early joint deformities.

Question 5277

Topic: 7. Hand and Wrist
A 9-year-old child presents with marked brachydactyly and deviation of the digits. Given the suspected diagnosis of Trichorhinophalangeal syndrome (TRPS) type 1, what other distinct clinical feature should the examiner expect to find?
. Blue sclerae
. A pear-shaped, bulbous nose
. Cafรฉ-au-lait spots
. Precocious puberty
. Polydactyly

Correct Answer & Explanation

. A pear-shaped, bulbous nose

Explanation

TRPS Type 1 is characterized by skeletal anomalies (brachydactyly, cone-shaped epiphyses) and distinct craniofacial features. These features include sparse hair, a pear-shaped bulbous nose, and a long, flat philtrum.

Question 5278

Topic: 7. Hand and Wrist
A 10-year-old boy presents with hip pain and a limp. He has fine, sparse hair and a pear-shaped nose. Radiographs show femoral head flattening mimicking Legg-Calvรฉ-Perthes disease. What hand deformity is most commonly associated with this syndrome?
. Arachnodactyly
. Broad thumbs and halluces
. Cone-shaped epiphyses
. Preaxial polydactyly
. Syndactyly of the middle and ring fingers

Correct Answer & Explanation

. Cone-shaped epiphyses

Explanation

Trichorhinophalangeal syndrome (TRPS) Type 1 frequently presents with Perthes-like avascular necrosis of the hip and classic cone-shaped epiphyses of the phalanges.

Question 5279

Topic: 7. Hand and Wrist

A 7-year-old girl presents with short stature and a 'hitchhiker thumb' deformity. Radiographs show a first metacarpal that is short and proximally placed. What is the primary defect in this skeletal dysplasia?

. Type II Collagen defect
. Sulfate transporter protein defect
. Fibroblast growth factor receptor 3 overactivity
. Cartilage oligomeric matrix protein mutation
. PTHR1 receptor mutation

Correct Answer & Explanation

. Sulfate transporter protein defect

Explanation

Correct Answer: BDiastrophic Dysplasia is caused by a mutation in the SLC26A2 gene, which encodes a sulfate transporter protein. This leads to undersulfation of proteoglycans in the cartilage matrix. Characteristic features include short-limbed dwarfism, 'hitchhiker thumbs' (due to a shortened first metacarpal), cauliflower ears, and severe clubfeet.

Question 5280

Topic: 7. Hand and Wrist

A patient presents with short stature, sparse hair, and a bulbous 'pear-shaped' nose. Radiographs of the hands show cone-shaped epiphyses of the middle phalanges. This constellation of findings is most consistent with:

. Langer-Giedion Syndrome
. Kniest Dysplasia
. Multiple Epiphyseal Dysplasia
. Schmid Metaphyseal Chondrodysplasia
. Jansen Metaphyseal Chondrodysplasia

Correct Answer & Explanation

. Langer-Giedion Syndrome

Explanation

Correct Answer: ALanger-Giedion Syndrome (Trichorhinophalangeal Syndrome Type II) is characterized by the triad of sparse hair, a bulbous nose, and multiple exostoses. Radiographically, cone-shaped epiphyses of the phalanges are a hallmark finding.

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