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2. Trauma MCQs

Practice Set 455 of 640

This practice set contains high-yield board review questions covering key concepts in 2. Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 9081

Topic: 2. Trauma

During a four-compartment fasciotomy of the lower leg for compartment syndrome, the surgeon must ensure the deep posterior compartment is adequately decompressed. Which muscle serves as the critical landmark within this specific compartment?

. Soleus
. Gastrocnemius
. Tibialis anterior
. Tibialis posterior
. Peroneus brevis

Correct Answer & Explanation

. Tibialis posterior

Explanation

The deep posterior compartment contains the tibialis posterior, flexor digitorum longus, and flexor hallucis longus. The tibialis posterior is the key deep structure that must be decompressed to fully release this compartment.

Question 9082

Topic: 2. Trauma

A 22-year-old male sustains a scaphoid waist fracture that progresses to a nonunion. The proximal pole of the scaphoid is highly susceptible to avascular necrosis because its major vascular supply enters the bone at the:

. Volar tubercle
. Dorsal ridge
. Proximal articular surface
. Scapholunate ligament insertion
. Lunotriquetral ligament insertion

Correct Answer & Explanation

. Dorsal ridge

Explanation

The major blood supply to the scaphoid is a branch of the radial artery that enters at the dorsal ridge and supplies the proximal pole via retrograde flow.

Question 9083

Topic: Upper Extremity Trauma

A collegiate baseball pitcher undergoes ulnar collateral ligament (UCL) reconstruction. The anterior bundle of the UCL is the primary restraint to valgus stress. Where is the precise anatomical footprint of this bundle on the ulna?

. Olecranon tip
. Coronoid process at the sublime tubercle
. Radial notch
. Supinator crest
. Ulnar styloid

Correct Answer & Explanation

. Coronoid process at the sublime tubercle

Explanation

The anterior bundle of the MUCL originates on the anteroinferior surface of the medial epicondyle and inserts on the sublime tubercle at the medial margin of the coronoid process.

Question 9084

Topic: 2. Trauma

Nonunion and avascular necrosis are common complications following fractures of the scaphoid waist due to its retrograde blood supply. Which artery provides the primary blood supply to the proximal pole of the scaphoid?

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

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The dorsal carpal branch of the radial artery enters the scaphoid at its distal waist and provides 70-80% of its blood supply. This supply flows in a retrograde fashion, placing the proximal pole at high risk for ischemia following a waist fracture.

Question 9085

Topic: Upper Extremity Trauma

During surgical reconstruction of the coracoclavicular (CC) ligaments for a high-grade acromioclavicular joint separation, anatomic placement of the drill holes is critical. Relative to the distal clavicle tip, what is the normal anatomic location of the CC ligament insertions?

. Conoid is lateral (approx 30mm), Trapezoid is medial (approx 45mm)
. Trapezoid is lateral (approx 25mm), Conoid is medial (approx 45mm)
. Conoid and Trapezoid insert at the exact same location (approx 30mm)
. Trapezoid is anterior, Conoid is posterior at 35mm
. Conoid is lateral (approx 45mm), Trapezoid is medial (approx 25mm)

Correct Answer & Explanation

. Trapezoid is lateral (approx 25mm), Conoid is medial (approx 45mm)

Explanation

The trapezoid ligament inserts more laterally on the clavicle, approximately 25 mm from the distal clavicle tip. The conoid ligament inserts more medially, approximately 45 mm from the distal tip.

Question 9086

Topic: 2. Trauma

A patient is undergoing an anterolateral approach to the distal tibia for plating of a pilon fracture. The superficial peroneal nerve (SPN) is at risk as it pierces the deep fascia. On average, at what distance proximal to the lateral malleolus does the SPN pierce the crural fascia?

. 2-5 cm
. 10-12 cm
. 18-20 cm
. 25-28 cm
. 30-35 cm

Correct Answer & Explanation

. 10-12 cm

Explanation

The superficial peroneal nerve pierces the deep crural fascia to become subcutaneous approximately 10 to 12 cm proximal to the tip of the lateral malleolus. It is highly vulnerable to iatrogenic injury during distal anterolateral approaches.

Question 9087

Topic: 2. Trauma

A patient develops compartment syndrome in the leg following a tibia fracture. A dual-incision fasciotomy is planned. Which of the following structures is located within the deep posterior compartment?

. Sural nerve
. Deep peroneal nerve
. Tibial nerve
. Superficial peroneal nerve
. Saphenous nerve

Correct Answer & Explanation

. Tibial nerve

Explanation

The deep posterior compartment of the leg contains the tibialis posterior, flexor hallucis longus, flexor digitorum longus, posterior tibial artery, and the tibial nerve.

Question 9088

Topic: Pelvic & Acetabular Trauma

During percutaneous sacroiliac joint fixation, a screw directed too anteriorly through the sacral ala places which neurovascular structure at greatest iatrogenic risk?

. Internal iliac artery
. External iliac vein
. L5 nerve root
. S1 nerve root
. Obturator nerve

Correct Answer & Explanation

. L5 nerve root

Explanation

The L5 nerve root courses directly over the anterior aspect of the sacral ala. Screws or drills that penetrate the anterior cortex of the ala place the L5 nerve root at significant risk of injury.

Question 9089

Topic: Lower Extremity Trauma

A 14-year-old with Ellis-van Creveld syndrome requires surgical intervention for recurrent patellar instability. The instability in this syndrome is primarily driven by which of the following combined structural factors?

. Severe genu varum and medial condyle aplasia
. Generalized ligamentous laxity without underlying bony deformity
. Hypoplastic lateral femoral condyle and genu valgum
. Isolated patella alta from a ruptured patellar tendon
. Congenital absence of the medial patellofemoral ligament

Correct Answer & Explanation

. Hypoplastic lateral femoral condyle and genu valgum

Explanation

Recurrent patellar dislocation is common in EVC syndrome due to the underlying severe genu valgum deformity coupled with hypoplasia of the lateral femoral condyle and lateral tibial plateau.

Question 9090

Topic: Lower Extremity Trauma

A 6-year-old child with Ellis-van Creveld syndrome presents to the orthopedic clinic with progressive, severe genu valgum. What is the primary anatomic abnormality responsible for this specific deformity in this syndrome?

. Medial distal femoral overgrowth
. Lateral distal femoral hypoplasia
. Medial proximal tibial overgrowth
. Lateral proximal tibial hypoplasia
. Proximal fibular overgrowth

Correct Answer & Explanation

. Lateral proximal tibial hypoplasia

Explanation

Genu valgum is a hallmark orthopedic manifestation of Ellis-van Creveld syndrome. It is primarily driven by hypoplasia and depression of the lateral proximal tibial plateau.

Question 9091

Topic: Upper Extremity Trauma

A 60-year-old male with chronic tophaceous gout presents with a large, draining mass over his olecranon.

Which of the following is an absolute indication for surgical excision of a gouty tophus?

. An asymptomatic tophus measuring less than 1 cm
. A tophus causing local skin necrosis and recurrent secondary infection
. The initial presentation of any tophus prior to medical therapy
. Persistently high serum uric acid levels > 10 mg/dL
. Concomitant radiographic evidence of chondrocalcinosis

Correct Answer & Explanation

. A tophus causing local skin necrosis and recurrent secondary infection

Explanation

Medical therapy is the first-line treatment for gouty tophi. Surgical excision is indicated when the tophus causes severe mechanical block, neurovascular compression, skin ulceration, or recurrent secondary infection.

Question 9092

Topic: Upper Extremity Trauma

A 55-year-old man undergoes excision of a large, chalky white mass overlying his olecranon. The surgeon suspects a gouty tophus. To accurately preserve the diagnostic crystals for histopathological examination, the specimen should be fixed in which of the following solutions?

. 10% Neutral buffered formalin
. Glutaraldehyde
. Absolute alcohol
. Bouin's solution
. Normal saline

Correct Answer & Explanation

. Absolute alcohol

Explanation

Monosodium urate crystals are water-soluble and will dissolve if placed in standard aqueous fixatives like 10% neutral buffered formalin. The specimen must be placed in absolute alcohol (ethanol) to preserve the crystals for visualization under polarized light microscopy.

Question 9093

Topic: 2. Trauma

A 6-year-old child with severe progressive bowing of the lower extremities presents for surgical evaluation. Based on the underlying condition shown in the representative radiograph, what is the most appropriate surgical stabilization method for a femoral shaft fracture?

. Rigid antegrade intramedullary nailing
. Flexible intramedullary nailing
. Telescoping intramedullary rodding
. External fixation
. Compression plating

Correct Answer & Explanation

. Telescoping intramedullary rodding

Explanation

The image demonstrates osteogenesis imperfecta with severe bowing and osteopenia. Telescoping intramedullary rods (e.g., Fassier-Duval) are the gold standard for surgical management in growing children to accommodate growth while preventing recurrent fractures and bowing.

Question 9094

Topic: 2. Trauma

An 8-year-old boy falls and sustains a mild injury to his right shoulder. X-rays reveal a centrally located, completely lytic lesion in the proximal humerus metaphysis with a piece of cortical bone resting at the dependent portion of the lesion. He has a minimally displaced pathological fracture. What is the best initial management?

. Immediate wide resection and allograft reconstruction
. Immobilization in a sling to allow fracture healing
. Open curettage and bone grafting
. Intralesional injection of methylprednisolone immediately
. Aspiration and injection of bone marrow aspirate concentrate immediately

Correct Answer & Explanation

. Immobilization in a sling to allow fracture healing

Explanation

The "fallen leaf" sign is pathognomonic for a Unicameral Bone Cyst (UBC). When a UBC presents with a pathological fracture, the initial treatment is to immobilize the limb to allow the fracture to heal, which occasionally leads to spontaneous obliteration of the cyst.

Question 9095

Topic: 2. Trauma

A 9-year-old boy presents with a pathologic fracture of the proximal humerus through a centrally located, completely lytic diaphyseal lesion demonstrating a "fallen leaf" sign on plain radiographs. What is the most appropriate initial management after the fracture has completely healed?

. Wide en bloc resection
. Prophylactic intramedullary nailing
. Observation or aspiration with methylprednisolone injection
. Radiation therapy
. Systemic Denosumab therapy

Correct Answer & Explanation

. Observation or aspiration with methylprednisolone injection

Explanation

The "fallen leaf" or "fallen fragment" sign is pathognomonic for a simple (unicameral) bone cyst. After the fracture heals (which occasionally obliterates the cyst), standard management involves observation or minimally invasive injections (corticosteroids or bone marrow aspirate) for persistent cysts.

Question 9096

Topic: 2. Trauma

A 9-year-old boy sustains a minor mechanical fall and presents with arm pain. Radiographs reveal a pathologic fracture through a centrally located, lytic diaphyseal lesion of the proximal humerus with a "fallen leaf" sign. What is the most appropriate initial management?

. Immediate curettage and bone grafting
. Wide en bloc resection
. Immobilization in a sling to allow fracture healing
. Intralesional steroid injection acutely
. Intravenous bisphosphonates

Correct Answer & Explanation

. Immobilization in a sling to allow fracture healing

Explanation

A unicameral bone cyst (UBC) presenting with a pathologic fracture is initially treated with immobilization to allow the fracture to heal. Surgery or injections are reserved for persistent cysts after the fracture has consolidated.

Question 9097

Topic: 2. Trauma

A 9-year-old boy sustains a minor fall and presents with arm pain. X-rays reveal a central, purely lytic lesion in the proximal humerus displaying a classic 'fallen leaf' sign. Aspiration of the lesion yields clear serous fluid. What is the most appropriate initial management for this presentation?

. Wide local excision and structural allografting
. Neoadjuvant chemotherapy followed by meticulous curettage
. Observation and cast immobilization to allow the fracture to heal
. Immediate curettage and filling with polymethylmethacrylate cement
. Amputation of the affected limb

Correct Answer & Explanation

. Observation and cast immobilization to allow the fracture to heal

Explanation

The presentation and the 'fallen leaf' sign are pathognomonic for a Unicameral Bone Cyst (UBC) complicated by a pathologic fracture. Initial management of a fractured UBC is typically immobilization to allow the fracture to heal, which occasionally promotes simultaneous spontaneous healing of the cyst.

Question 9098

Topic: Lower Extremity Trauma



A patient's lower extremity radiographs reveal a mechanical lateral distal femoral angle (mLDFA) of 81 degrees and a medial proximal tibial angle (MPTA) of 87 degrees. The joint line convergence angle (JLCA) is 2 degrees. What is the primary source of the deformity?

. Proximal tibia (varus)
. Distal femur (valgus)
. Distal femur (varus)
. Proximal tibia (valgus)
. Intra-articular knee joint wear

Correct Answer & Explanation

. Distal femur (valgus)

Explanation

A normal mLDFA is approximately 87-88 degrees. An mLDFA of 81 degrees indicates a valgus deformity of the distal femur. Because the MPTA (normal 87 degrees) and JLCA (normal 0-2 degrees) are normal, the deformity is isolated to the distal femur.

Question 9099

Topic: 2. Trauma

When performing fixator-assisted nailing (FAN) for distal femoral deformity correction, what is the primary advantage of placing the external fixator before reaming and nail insertion?

. It prevents thermal necrosis of the diaphysis
. It maintains the achieved anatomical alignment during reaming and nail passage
. It allows for simultaneous lengthening during nail insertion
. It eliminates the need for blocking (Poller) screws
. It accelerates the regenerate consolidation time

Correct Answer & Explanation

. It maintains the achieved anatomical alignment during reaming and nail passage

Explanation

In FAN, the external fixator is temporarily applied to rigidly hold the acutely corrected deformity in precise alignment. This ensures that the alignment is maintained while the intramedullary canal is reamed and the nail is passed.

Question 9100

Topic: Lower Extremity Trauma

A surgeon is planning a lateral opening wedge osteotomy of the distal femur to correct a valgus deformity. To prevent unintended sagittal plane deformity (flexion or extension), where should the mechanical hinge be aligned?

. Anterior to the mid-axial line of the femur
. Exactly on the mid-axial line in the sagittal plane, on the anterior cortex
. Posterior to the posterior femoral cortex
. On the medial cortex, along the mid-axial line in the sagittal plane
. On the lateral cortex, along the mid-axial line in the sagittal plane

Correct Answer & Explanation

. On the medial cortex, along the mid-axial line in the sagittal plane

Explanation

For a purely coronal plane correction (lateral opening wedge), the hinge must be located on the opposite (medial) cortex. To avoid creating iatrogenic recurvatum or procurvatum, the hinge must lie exactly on the sagittal mid-axial line.

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