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1. General Principles & Basic Science MCQs

Practice Set 472 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 9421

Topic: 1. General Principles & Basic Science

What is the typical age of onset for Dysplasia Epiphysealis Hemimelica (DEH)?

. Birth to 1 year
. 15 to 25 years
. 2 to 14 years
. 30 to 45 years
. Over 50 years

Correct Answer & Explanation

. 2 to 14 years

Explanation

Correct Answer: 2 to 14 yearsDysplasia epiphysealis hemimelica (DEH) is a rare skeletal developmental disorder affecting the epiphyses in young children. The age of onset is usually between 2 and 14 years.

Question 9422

Topic: 1. General Principles & Basic Science

Regarding the epidemiology of Dysplasia Epiphysealis Hemimelica (DEH), which of the following statements is correct?

. It affects females twice as frequently as males
. The incidence is approximately 1 in 10,000
. It affects males twice as frequently as females
. It is exclusively found in patients of Middle Eastern descent
. It has a strong autosomal dominant inheritance pattern

Correct Answer & Explanation

. It affects males twice as frequently as females

Explanation

Correct Answer: It affects males twice as frequently as femalesDEH is a very rare condition with an incidence of 1 in 1,000,000. Males are affected twice as frequently as females. The etiology remains unknown, and it is not described as having a strong autosomal dominant inheritance or specific ethnic exclusivity in standard texts.

Question 9423

Topic: 1. General Principles & Basic Science

The term 'hemimelic' in Dysplasia Epiphysealis Hemimelica refers to which of the following characteristics?

. Involvement of either the medial or lateral side of the epiphysis
. Involvement of exactly half of the body's skeleton
. The presence of half-formed cartilage caps
. Involvement of only the upper or lower extremity
. The tendency to affect only one hemisphere of the brain

Correct Answer & Explanation

. Involvement of either the medial or lateral side of the epiphysis

Explanation

Correct Answer: Involvement of either the medial or lateral side of the epiphysisCharacteristically, the involvement in DEH is hemimelic, meaning that only one half (either the medial or the lateral side) of the affected epiphysis is involved.

Question 9424

Topic: Infection, Pharmacology & VTE

Which of the following is the most common presenting symptom complex for a patient with Dysplasia Epiphysealis Hemimelica?

. Pathologic fracture and systemic fever
. Rapidly growing soft tissue mass with skin ulceration
. Bone-hard mass, deformity, aching pains, and limited range of motion
. Painless, mobile, rubbery subcutaneous nodules
. Night pain dramatically relieved by NSAIDs

Correct Answer & Explanation

. Bone-hard mass, deformity, aching pains, and limited range of motion

Explanation

Correct Answer: Bone-hard mass, deformity, aching pains, and limited range of motionThe most common presenting symptoms of DEH include the presence of a mass with the consistency of bone, deformity, aching pains, and limited range of motion in the affected joint.

Question 9425

Topic: 1. General Principles & Basic Science

The term 'hemimelica' in Dysplasia Epiphysealis Hemimelica refers to which characteristic pattern of involvement?

. Involvement of exactly half of the body's total epiphyses
. Involvement restricted to either the upper or lower extremity exclusively
. Involvement of either the medial or lateral side of the affected epiphysis
. Involvement of the diaphysis and metaphysis but sparing the epiphysis

Correct Answer & Explanation

. Involvement of either the medial or lateral side of the affected epiphysis

Explanation

Correct Answer: Involvement of either the medial or lateral side of the affected epiphysisCharacteristically, the involvement in DEH is hemimelic, meaning that only one half (either the medial or the lateral side) of the epiphysis is involved.

Question 9426

Topic: Infection, Pharmacology & VTE

Which of the following constellations of symptoms is most characteristic for a child presenting with Dysplasia Epiphysealis Hemimelica (DEH)?

. Soft, fluctuant mass with severe night pain relieved by NSAIDs
. Bone-hard mass, deformity, aching pains, and limited range of motion
. Rapidly growing, warm, erythematous mass with systemic fever
. Painless, mobile soft tissue mass with associated nerve palsy

Correct Answer & Explanation

. Bone-hard mass, deformity, aching pains, and limited range of motion

Explanation

Correct Answer: Bone-hard mass, deformity, aching pains, and limited range of motionThe most common presenting symptoms of DEH include the presence of a mass with the consistency of bone, deformity, aching pains, and a limited range of motion in the affected joint.

Question 9427

Topic: 1. General Principles & Basic Science

Regarding the epidemiology of Dysplasia Epiphysealis Hemimelica (DEH), which of the following statements is most accurate?

. It affects females twice as often as males
. The incidence is approximately 1 in 10,000
. The typical age of onset is between 2 and 14 years
. It predominantly involves the upper extremities
. It is inherited in an autosomal dominant pattern

Correct Answer & Explanation

. The typical age of onset is between 2 and 14 years

Explanation

Correct Answer: The typical age of onset is between 2 and 14 yearsDysplasia Epiphysealis Hemimelica is a rare developmental disorder with an onset usually between 2 and 14 years of age. It affects males twice as frequently as females, has an incidence of 1 in 1,000,000, and upper limb involvement is extremely rare.

Question 9428

Topic: 1. General Principles & Basic Science

The term 'hemimelica' in Dysplasia Epiphysealis Hemimelica describes which specific characteristic of the disease?

. It affects only half of the body (unilateral)
. It involves only the upper or lower half of the body
. It is confined to either the medial or lateral side of the affected epiphysis
. It affects only the proximal half of the limb
. It involves half of the diaphysis

Correct Answer & Explanation

. It is confined to either the medial or lateral side of the affected epiphysis

Explanation

Correct Answer: It is confined to either the medial or lateral side of the affected epiphysisCharacteristically, the involvement in DEH is hemimelic, meaning that the lesion is localized to either the medial or the lateral epiphyseal side of the affected bone.

Question 9429

Topic: 1. General Principles & Basic Science

A 9-year-old male presents with the swelling shown below. He reports aching pain and limited range of motion. What is the estimated incidence of the underlying condition in the general population?




. 1 in 10,000
. 1 in 50,000
. 1 in 100,000
. 1 in 500,000
. 1 in 1,000,000

Correct Answer & Explanation

. 1 in 1,000,000

Explanation

Correct Answer: 1 in 1,000,000The image shows a clinical presentation of Dysplasia Epiphysealis Hemimelica (DEH). DEH is an extremely rare skeletal developmental disorder with an estimated incidence of 1 in 1,000,000.

Question 9430

Topic: 1. General Principles & Basic Science

A 12-year-old boy presents with knee pain and the imaging findings shown below. The mass is protruding into the popliteal fossa. Based on the diagnosis of Dysplasia Epiphysealis Hemimelica, what is the most likely gender distribution for this condition?




. Males and females are affected equally
. Males are affected twice as frequently as females
. Females are affected twice as frequently as males
. Males are affected five times as frequently as females
. Females are affected five times as frequently as males

Correct Answer & Explanation

. Males are affected twice as frequently as females

Explanation

Correct Answer: Males are affected twice as frequently as femalesThe imaging demonstrates DEH of the distal femoral epiphysis. Epidemiologically, males are affected twice as frequently as females by this rare developmental disorder.

Question 9431

Topic: 1. General Principles & Basic Science

Dysplasia epiphysealis hemimelica (DEH) is a rare developmental disorder. Which of the following statements regarding the epidemiology of DEH is correct?

. It affects females twice as frequently as males.
. The incidence is approximately 1 in 10,000.
. The typical age of onset is between 20 and 30 years.
. Males are affected twice as frequently as females.
. It is predominantly an upper limb disorder.

Correct Answer & Explanation

. Males are affected twice as frequently as females.

Explanation

Correct Answer: Males are affected twice as frequently as females.DEH is a rare skeletal developmental disorder with an incidence of 1 in 1,000,000. Males are affected twice as frequently as females. The age of onset is usually between 2 and 14 years, and it predominantly affects the lower limbs.

Question 9432

Topic: 1. General Principles & Basic Science

The term 'hemimelica' in Dysplasia Epiphysealis Hemimelica refers to which of the following characteristic patterns of involvement?

. Involvement of exactly half of the body's total joints.
. Concomitant involvement of the ipsilateral upper and lower limbs.
. Involvement restricted to either the medial or lateral side of the epiphysis.
. Symmetrical involvement of bilateral lower extremities.
. Involvement of the metaphysis and diaphysis exclusively.

Correct Answer & Explanation

. Involvement restricted to either the medial or lateral side of the epiphysis.

Explanation

Correct Answer: Involvement restricted to either the medial or lateral side of the epiphysis.Characteristically, the involvement in DEH is hemimelic, meaning that only one half (either the medial or the lateral side) of the affected epiphysis is involved. This leads to asymmetric growth and subsequent joint deformity.

Question 9433

Topic: Surgical Anatomy & Approaches

Based on the imaging provided of a patient with Dysplasia Epiphysealis Hemimelica, the mass is protruding from the distal femoral epiphysis into the popliteal fossa. Which of the following structures is at highest risk of compression from this specific lesion?



. Femoral nerve
. Popliteal artery
. Common peroneal nerve at the fibular head
. Anterior tibial artery
. Saphenous nerve

Correct Answer & Explanation

. Popliteal artery

Explanation

Correct Answer: Popliteal arteryThe MRI slide in the sagittal plane shows a protruding bone mass from the distal femoral epiphysis extending directly into the popliteal fossa. The popliteal fossa contains the popliteal artery, popliteal vein, and tibial nerve. A large space-occupying lesion in this area places these neurovascular structures, particularly the popliteal artery, at risk of compression.

Question 9434

Topic: 1. General Principles & Basic Science

Which of the following is true regarding the genetic etiology of Dysplasia Epiphysealis Hemimelica (DEH)?

. It is strongly associated with EXT1 mutations
. It exhibits an autosomal dominant inheritance pattern
. It arises sporadically without a known inherited genetic mutation
. It is commonly associated with NF1 mutations
. It is transmitted via mitochondrial inheritance

Correct Answer & Explanation

. It arises sporadically without a known inherited genetic mutation

Explanation

DEH is a rare developmental disorder that occurs sporadically. Unlike Hereditary Multiple Exostoses, it is not inherited and is not associated with EXT gene mutations.

Question 9435

Topic: 1. General Principles & Basic Science

DEH most frequently affects which anatomical aspect of the involved extremity?

. Anterior
. Posterior
. Lateral
. Medial
. Central

Correct Answer & Explanation

. Medial

Explanation

DEH predominantly affects the medial side of the limb (hemimelica) in approximately 70% of cases. The lateral side is involved much less frequently.

Question 9436

Topic: 1. General Principles & Basic Science

Dysplasia Epiphysealis Hemimelica (DEH) is characterized by asymmetric cartilage overgrowth. Which aspect of the joint is most frequently involved, and what is the typical inheritance pattern?

. Lateral aspect; autosomal dominant
. Medial aspect; sporadic
. Lateral aspect; sporadic
. Medial aspect; autosomal dominant
. Bilateral symmetrical; X-linked recessive

Correct Answer & Explanation

. Medial aspect; sporadic

Explanation

DEH is a rare, non-hereditary (sporadic) developmental skeletal disorder. It has a strong predilection for involving the medial (inner half) of the affected epiphysis.

Question 9437

Topic: 1. General Principles & Basic Science

Parents of a 3-year-old boy diagnosed with Trevor disease ask about the likelihood of their future children inheriting the condition. What is the correct genetic counseling to provide?

. It follows an autosomal dominant pattern with 50% risk.
. It is an X-linked recessive disorder.
. It is an autosomal recessive condition.
. It requires a maternal mitochondrial mutation.
. It occurs sporadically with no known inheritance pattern.

Correct Answer & Explanation

. It occurs sporadically with no known inheritance pattern.

Explanation

Trevor disease (DEH) is a sporadic developmental error of epiphyseal cartilage. It is not hereditary, and there is no increased risk for subsequent pregnancies.

Question 9438

Topic: 1. General Principles & Basic Science

Dysplasia Epiphysealis Hemimelica is characterized by asymmetric epiphyseal overgrowth. Which portion of the affected epiphysis is most frequently involved?

. Medial half
. Lateral half
. Anterior half
. Posterior half
. Central core

Correct Answer & Explanation

. Medial half

Explanation

DEH typically affects only half of the epiphysis (hemimelic). The medial half of the epiphysis is affected more frequently than the lateral half, commonly resulting in varus deformities.

Question 9439

Topic: 1. General Principles & Basic Science

Overgrowth of the medial aspect of the distal femoral epiphysis due to Trevor disease is most likely to result in which of the following clinical deformities?

. Genu valgum
. Genu varum
. Genu recurvatum
. Internal tibial torsion
. Patella baja

Correct Answer & Explanation

. Genu varum

Explanation

Because DEH acts as an asymmetric space-occupying cartilaginous mass, overgrowth on the medial side of the knee joint opens the medial joint space and typically pushes the limb into a genu varum deformity.

Question 9440

Topic: 1. General Principles & Basic Science

During the surgical excision of an intra-articular DEH lesion of the knee, removing too much tissue can lead to poor outcomes. To preserve joint function, the surgeon must be particularly careful not to resect which structure?

. The hypertrophic hyaline cartilage cap
. The ossified stalk of the lesion
. The underlying normal native articular cartilage
. The inflamed synovial plica
. The surrounding thickened perichondrium

Correct Answer & Explanation

. The underlying normal native articular cartilage

Explanation

The primary challenge in excising DEH lesions is defining the plane between the hamartomatous overgrowth and the native articular cartilage. Inadvertent resection of the native cartilage can accelerate postoperative osteoarthritis.

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