Menu

4. Pediatrics MCQs

Practice Set 261 of 334

This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 5201

Topic: 4. Pediatrics

In pediatric bone growth and trauma, physeal fractures most commonly propagate through which specific histologic zone of the growth plate?

. Reserve (resting) zone
. Proliferative zone
. Hypertrophic zone
. Primary spongiosa
. Secondary spongiosa

Correct Answer & Explanation

. Hypertrophic zone

Explanation

Physeal fractures (Salter-Harris fractures) typically fail through the zone of hypertrophy. This zone lacks the structural integrity of the other zones because the cells are enlarged and the extracellular matrix volume is reduced.

Question 5202

Topic: Pediatric Upper Extremity & Spine

A 14-year-old female presents for evaluation of adolescent idiopathic scoliosis (AIS). She has a right thoracic curve of 55 degrees. Her neurologic exam reveals normal strength and sensation, but you note that her superficial abdominal reflexes are briskly present on the left and entirely absent on the right. What is the most appropriate next step?

. Proceed with TLSO bracing
. Schedule for immediate posterior spinal fusion
. Order a total spine MRI
. Reassure the patient, as this is a normal variant in structural curves
. Perform an electromyography (EMG) of the abdominal wall

Correct Answer & Explanation

. Order a total spine MRI

Explanation

Asymmetric superficial abdominal reflexes in a patient with presumed AIS are a 'red flag' for an underlying intraspinal anomaly, such as syringomyelia, Chiari malformation, or a tethered cord. This reflex is elicited by stroking the skin of the abdomen, causing umbilicus deviation. Atypical curve patterns (left thoracic), rapid progression, pain, or asymmetric abdominal reflexes mandate an MRI of the entire neuraxis prior to any surgical intervention.

Question 5203

Topic: Pediatric Upper Extremity & Spine

In the Lenke Classification system for Adolescent Idiopathic Scoliosis, the lumbar spine modifier is determined by the relationship of the Center Sacral Vertical Line (CSVL) to the apical lumbar vertebra. Which of the following defines a Lenke Lumbar Modifier B?

. The CSVL passes directly between the pedicles of the apical lumbar vertebra
. The CSVL falls completely lateral to the lateral margin of the apical vertebral body
. The CSVL falls between the medial border of the pedicle and the lateral margin of the apical vertebral body
. The CSVL intersects the apical intervertebral disc instead of the vertebral body
. The CSVL passes outside the thoracic cage boundaries

Correct Answer & Explanation

. The CSVL falls between the medial border of the pedicle and the lateral margin of the apical vertebral body

Explanation

The Lenke Lumbar Modifiers are: A) CSVL passes between the pedicles of the apical lumbar vertebra. B) CSVL falls between the medial border of the pedicle and the lateral margin of the apical vertebral body. C) CSVL falls completely lateral to the lateral margin of the apical vertebral body. Modifier B indicates a structural but mild lumbar curve.

Question 5204

Topic: Pediatric Upper Extremity & Spine

A 14-year-old female with Adolescent Idiopathic Scoliosis has a main thoracic curve of 55 degrees and a lumbar curve of 35 degrees. On lateral bending radiographs, the lumbar curve bends out to 15 degrees. According to the Lenke classification, what type of curve is this?

. Lenke 1 (Main Thoracic)
. Lenke 2 (Double Thoracic)
. Lenke 3 (Double Major)
. Lenke 5 (Thoracolumbar/Lumbar)
. Lenke 6 (Thoracolumbar/Lumbar-Main Thoracic)

Correct Answer & Explanation

. Lenke 1 (Main Thoracic)

Explanation

In the Lenke classification, a minor curve that corrects to less than 25 degrees on side-bending radiographs is considered non-structural. Since the lumbar curve bends out to 15 degrees, it is non-structural, making this a Lenke 1 (Main Thoracic) curve pattern.

Question 5205

Topic: 4. Pediatrics
A 5-year-old child sustains a Gartland type III supracondylar humerus fracture. On presentation, the hand is pink but the radial pulse is absent. Following emergent closed reduction and percutaneous pinning, the fracture is anatomically reduced, but the radial pulse remains absent. The hand remains warm with a capillary refill of less than 2 seconds. What is the most appropriate next step?
. Immediate open exploration of the brachial artery
. Angiography of the upper extremity
. Observation and close clinical monitoring
. Application of a warm compress and delayed exploration at 48 hours
. Removal of the pins and conversion to open reduction

Correct Answer & Explanation

. Observation and close clinical monitoring

Explanation

In a well-perfused 'pink, pulseless' hand following anatomic reduction and pinning of a pediatric supracondylar humerus fracture, the standard of care is close clinical observation. Collateral circulation is typically adequate to perfuse the limb, and the radial pulse usually returns within days to weeks.

Question 5206

Topic: Pediatric Lower Extremity

During the correction of idiopathic clubfoot using the Ponseti method, manipulation and casting must follow a specific sequence. Which component of the deformity is corrected first, and what is the maneuver used to achieve it?

. Equinus; achieved by immediate dorsiflexion of the ankle
. Varus; achieved by everting the calcaneus
. Adductus; achieved by abducting the midfoot with counter-pressure on the calcaneocuboid joint
. Cavus; achieved by elevating the first ray to supinate the forefoot
. Equinus; achieved by a percutaneous Achilles tenotomy prior to any casting

Correct Answer & Explanation

. Cavus; achieved by elevating the first ray to supinate the forefoot

Explanation

The Ponseti method corrects deformities in the order of CAVE (Cavus, Adductus, Varus, Equinus). The cavus is corrected first by supinating the forefoot (elevating the first ray) to align it with the already supinated hindfoot.

Question 5207

Topic: 4. Pediatrics
A 13-year-old boy sustains a severe external rotation ankle injury. Radiographs reveal an isolated Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis (Tillaux fracture). This fracture pattern is uniquely dictated by the asymmetrical closure pattern of the distal tibial physis. Which quadrant of the distal tibial physis is the last to close?
. Anteromedial
. Posteromedial
. Central
. Anterolateral
. Posterolateral

Correct Answer & Explanation

. Anterolateral

Explanation

The distal tibial physis closes over an 18-month period starting centrally, then anteromedial, posteromedial, and finally anterolateral. Because the anterolateral physis is open last, avulsion by the anterior inferior tibiofibular ligament causes a Tillaux fracture.

Question 5208

Topic: 4. Pediatrics

A 10-year-old male sustains an anterior cruciate ligament (ACL) tear. His skeletal age indicates substantial remaining growth. Which of the following surgical techniques for ACL reconstruction poses the highest risk of physeal arrest and subsequent angular deformity?

. All-epiphyseal reconstruction
. Physeal-sparing iliotibial band (MacIntosh) technique
. Transphyseal reconstruction with an 8-mm soft tissue graft placed centrally
. Over-the-top femoral and transphyseal tibial soft-tissue technique
. Transphyseal reconstruction using a bone-patellar tendon-bone autograft

Correct Answer & Explanation

. Over-the-top femoral and transphyseal tibial soft-tissue technique

Explanation

Using a bone plug across an open physis significantly increases the risk of premature physeal closure, growth arrest, and angular deformity. Soft tissue grafts placed vertically and centrally through the physis (typically <8mm) have a lower risk. Physeal-sparing and all-epiphyseal techniques are specifically designed to avoid the physis entirely in skeletally immature patients.

Question 5209

Topic: Pediatric Hip

A 28-year-old female runner complains of deep anterior hip pain. An AP pelvic radiograph demonstrates the 'crossover sign'. This radiographic finding is indicative of which pathoanatomical condition?

. Cam-type femoroacetabular impingement
. Focal or global acetabular retroversion
. Developmental dysplasia of the hip (DDH)
. Coxa profunda
. Femoral retroversion

Correct Answer & Explanation

. Focal or global acetabular retroversion

Explanation

The crossover sign occurs when the anterior wall of the acetabulum crosses lateral to the posterior wall on an AP pelvis radiograph. It is the hallmark radiographic sign of focal or global acetabular retroversion, a form of pincer impingement.

Question 5210

Topic: Pediatric Hip

Restoring the anatomical hip center during THA for developmental dysplasia of the hip (DDH) is preferred over placing the cup in a high hip center. Biomechanically, what is the primary advantage of lowering the hip center to its true anatomical location?

. Decreases the abductor moment arm and increases joint reactive force
. Increases the abductor moment arm and decreases joint reactive force
. Increases both the abductor moment arm and joint reactive force
. Decreases both the abductor moment arm and joint reactive force
. Shifts the center of gravity laterally, reducing superior sheer forces

Correct Answer & Explanation

. Increases the abductor moment arm and decreases joint reactive force

Explanation

Restoring the anatomical (inferior and medial) hip center increases the mechanical advantage (moment arm) of the abductor muscles. This reduces the muscle force required for pelvic stability, thereby significantly decreasing the overall joint reactive force.

Question 5211

Topic: 4. Pediatrics

A 13-year-old Little League baseball pitcher presents with 3 months of progressive throwing arm shoulder pain. Radiographs demonstrate widening and irregularity of the proximal humeral physis. What is the primary pathophysiology of this condition?

. Avascular necrosis of the proximal humeral epiphysis
. Avulsion fracture of the greater tuberosity
. Salter-Harris Type I stress fracture of the proximal humeral physis
. Traction apophysitis of the coracoid process
. Osteochondritis dissecans of the humeral head

Correct Answer & Explanation

. Salter-Harris Type I stress fracture of the proximal humeral physis

Explanation

Little League Shoulder is an overuse injury in skeletally immature throwing athletes. The rotational torque applied during the throwing motion causes a repetitive stress injury to the proximal humeral physis, functioning essentially as a chronic Salter-Harris Type I stress fracture. This manifests as widening and sclerosis on radiographs.

Question 5212

Topic: 4. Pediatrics

A 19-year-old rugby player sustains a severe blow to the medial shoulder and presents with a clinically posterior sternoclavicular joint dislocation. The patient is hemodynamically stable but dyspneic. Which of the following is true regarding this injury?

. Closed reduction is strictly contraindicated in the emergency department.
. The injury is most likely a true sternoclavicular ligamentous dislocation.
. The medial clavicle physis is typically closed by age 16, confirming a true dislocation.
. Cardiothoracic surgery backup should be available during reduction attempts.
. It invariably requires urgent open reduction and internal fixation with a plate.

Correct Answer & Explanation

. Cardiothoracic surgery backup should be available during reduction attempts.

Explanation

Posterior sternoclavicular dislocations risk compression of mediastinal structures (trachea, esophagus, great vessels). Due to the potential for catastrophic vascular injury during reduction, cardiothoracic surgery backup is essential. In a 19-year-old, this injury is often a Salter-Harris physeal fracture-separation, as the medial clavicle physis is the last to close (typically ages 22-25).

Question 5213

Topic: Pediatric Upper Extremity & Spine

A 10-year-old Little League baseball pitcher presents with medial elbow pain. Radiographs reveal widening of the medial epicondyle apophysis. Which of the following is the primary static restraint to valgus stress of the elbow during the late cocking phase of throwing?

. Posterior bundle of the MCL
. Anterior bundle of the MCL
. Transverse bundle of the MCL
. Radiocapitellar joint
. Flexor-pronator mass

Correct Answer & Explanation

. Anterior bundle of the MCL

Explanation

The anterior bundle of the medial collateral ligament (MCL) is the primary static restraint to valgus stress at the elbow between 30 and 90 degrees of flexion. In children with open physes, the weak link is the apophysis, leading to 'Little League Elbow' (medial epicondyle apophysitis) rather than a ligamentous tear.

Question 5214

Topic: 4. Pediatrics

A 12-year-old Little League pitcher presents with progressive, activity-related shoulder pain. Radiographs reveal widening and lateral fragmentation of the proximal humeral physis. What is the most appropriate initial treatment?

. Corticosteroid injection into the subacromial space.
. Immediate surgical stabilization with percutaneous pinning.
. Complete cessation of throwing for 3 months, followed by a progressive throwing program.
. Physical therapy for aggressive capsular stretching.
. Continuation of throwing with a strict pitch-count limit.

Correct Answer & Explanation

. Complete cessation of throwing for 3 months, followed by a progressive throwing program.

Explanation

'Little League Shoulder' is a stress fracture (epiphysiolysis) of the proximal humeral physis due to repetitive torsional forces from throwing. The standard of care is complete cessation of throwing (rest) for typically 3 months until symptoms resolve and radiographic healing is noted, followed by physical therapy and a gradual return to throwing.

Question 5215

Topic: 4. Pediatrics

A 19-year-old male football player sustains a high-energy blow to the medial shoulder. He presents with severe pain and a visually absent medial clavicle. CT scan shows posterior displacement of the medial clavicle. Given his age, what is the most likely true pathology?

. True sternoclavicular joint dislocation
. Salter-Harris type I or II fracture of the medial clavicle
. Comminuted midshaft clavicle fracture
. Acromioclavicular joint separation
. First rib fracture

Correct Answer & Explanation

. Salter-Harris type I or II fracture of the medial clavicle

Explanation

The medial clavicle physis is the last physis in the body to close, typically fusing between ages 20 and 25. Therefore, a posterior 'dislocation' in a 19-year-old is almost always a Salter-Harris physeal fracture-separation rather than a true joint dislocation.

Question 5216

Topic: 4. Pediatrics

What is the primary blood supply to the femoral head in a 6-year-old child?

. Artery of the ligamentum teres
. Medial femoral circumflex artery (lateral epiphyseal vessels)
. Lateral femoral circumflex artery (medial epiphyseal vessels)
. Inferior gluteal artery
. Metaphyseal vessels traversing the physis

Correct Answer & Explanation

. Medial femoral circumflex artery (lateral epiphyseal vessels)

Explanation

In children between the ages of 3 and 10 years, the medial femoral circumflex artery (MFCA), specifically its lateral epiphyseal branches, provides the dominant blood supply to the femoral head. The metaphyseal supply is blocked by the developing physis, and the artery of the ligamentum teres does not contribute significantly until later childhood/adolescence.

Question 5217

Topic: 4. Pediatrics

In the vascular anatomy of the growing long bone, the perichondrial ring of LaCroix and the groove of Ranvier are critical structures. The primary function of the vessels in the groove of Ranvier is to:

. Provide the primary blood supply to the secondary ossification center
. Supply the central resting zone of the physis
. Provide blood supply to the peripheral physis and contribute to latitudinal growth
. Form a vascular anastomosis with the medullary cavity vessels
. Supply the articular cartilage via diffusion

Correct Answer & Explanation

. Provide blood supply to the peripheral physis and contribute to latitudinal growth

Explanation

The groove of Ranvier contains a rich vascular network that supplies the peripheral aspect of the physis. It provides chondrocytes for latitudinal (appositional/width) growth of the physis, whereas the epiphyseal vessels supply the central regions for longitudinal growth.

Question 5218

Topic: 4. Pediatrics

A 4-year-old child presents with a spiral fracture of the tibia, without fibula involvement, after a seemingly trivial injury (e.g., twisting fall while playing). The parents describe a consistent story. This fracture pattern is classically known as a:

. Toddler's fracture
. Greenstick fracture
. Torus fracture
. Growth plate fracture (Salter-Harris type I)
. Bowed fracture

Correct Answer & Explanation

. Toddler's fracture

Explanation

A 'toddler's fracture' is a classic, non-displaced or minimally displaced spiral or oblique fracture of the distal tibia, occurring in young children (typically 9 months to 3 years old) with low-energy rotational forces. It often presents with refusal to bear weight or limp. Greenstick and torus fractures are incomplete fractures typically of the diaphysis or metaphysis due to bending forces. Growth plate fractures involve the physis. While a spiral fracture can raise suspicion for non-accidental injury, in the context of a 'trivial' injury and consistent story, toddler's fracture is the most likely and benign diagnosis for this pattern.

Question 5219

Topic: 4. Pediatrics
A 2-year-old child sustains a Salter-Harris Type I fracture of the distal tibia. What is the primary concern for long-term complications with this type of growth plate injury?
. Avascular necrosis.
. Nonunion.
. Compartment syndrome.
. Angular deformity or limb length discrepancy due to growth arrest.
. Post-traumatic arthritis.

Correct Answer & Explanation

. Angular deformity or limb length discrepancy due to growth arrest.

Explanation

Salter-Harris Type I and II fractures, which involve the physis (growth plate) or physis and metaphysis respectively, are at risk for growth arrest and subsequent angular deformity or limb length discrepancy. This is due to potential damage to the chondrocytes in the growth plate. Type I fractures typically have a good prognosis if reduced anatomically, but any physeal injury carries this risk. Avascular necrosis is rare in these fractures. Nonunion is also rare. Compartment syndrome is a concern with any significant trauma but not a specific long-term complication of Type I Salter-Harris. Post-traumatic arthritis is more common with intra-articular fractures (e.g., Salter-Harris Type III or IV).

Question 5220

Topic: Pediatric Upper Extremity & Spine

Which of the following is the most sensitive and widely used scoring system to quantify injury severity in polytrauma patients, primarily based on anatomical injuries?

. Glasgow Coma Scale (GCS).
. Injury Severity Score (ISS).
. Revised Trauma Score (RTS).
. Abbreviated Injury Scale (AIS).
. Trauma and Injury Severity Score (TRISS).

Correct Answer & Explanation

. Injury Severity Score (ISS).

Explanation

The Injury Severity Score (ISS) is the most widely used scoring system for quantifying overall injury severity in polytrauma patients. It is calculated from the Abbreviated Injury Scale (AIS), which assigns a score from 1 (minor) to 6 (unsurvivable) for injuries to different body regions. The ISS is the sum of the squares of the highest AIS scores in the three most severely injured body regions. GCS assesses neurological status. RTS is a physiological score. TRISS combines ISS, RTS, and age to predict survival. AIS is a component of ISS, not an overall severity score itself.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page