Menu

2. Trauma MCQs

Practice Set 29 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 561

Topic: Pelvic & Acetabular Trauma

Which of the following ligaments is the strongest in the body and provides the primary stability to the posterior pelvic ring against vertical shear forces?

. Anterior sacroiliac ligament
. Sacrotuberous ligament
. Sacrospinous ligament
. Interosseous sacroiliac ligament
. Iliolumbar ligament

Correct Answer & Explanation

. Interosseous sacroiliac ligament

Explanation

The interosseous sacroiliac ligament is the strongest ligament in the body. It plays the primary role in stabilizing the posterior pelvic ring, particularly against vertical shear stresses.

Question 562

Topic: 2. Trauma

A 25-year-old male sustains a severe closed tibial shaft fracture. Which of the following pressure measurements represents the most widely accepted threshold for performing a four-compartment fasciotomy to treat acute compartment syndrome?

. Absolute compartment pressure > 15 mmHg
. Absolute compartment pressure > 20 mmHg
. Delta pressure (Diastolic blood pressure - Compartment pressure) < 30 mmHg
. Delta pressure (Mean arterial pressure - Compartment pressure) > 40 mmHg
. Delta pressure (Systolic blood pressure - Compartment pressure) < 10 mmHg

Correct Answer & Explanation

. Delta pressure (Diastolic blood pressure - Compartment pressure) < 30 mmHg

Explanation

A delta pressure (diastolic blood pressure minus intracompartmental pressure) of less than 30 mmHg is the standard threshold indicating inadequate tissue perfusion and the need for emergent fasciotomy.

Question 563

Topic: 2. Trauma

In the pathophysiology of acute compartment syndrome, what is the initial event at the microvascular level?

. Arterial occlusion
. Capillary endothelial damage
. Venous outflow obstruction
. Lymphatic stasis
. Arteriovenous shunting

Correct Answer & Explanation

. Venous outflow obstruction

Explanation

The initial microvascular event in compartment syndrome is venous outflow obstruction due to increased tissue pressure. This causes secondary increases in capillary pressure, transudation of fluid, and ultimately compromised arterial inflow.

Question 564

Topic: Pelvic & Acetabular Trauma

Where is the anatomically correct position to apply a pelvic binder to effectively reduce a suspected 'open book' pelvic ring injury?

. At the level of the iliac crests
. At the level of the anterior superior iliac spines
. Centered over the greater trochanters
. Below the level of the lesser trochanters
. Around the mid-thighs

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

A pelvic binder must be centered over the greater trochanters to directly close the pelvic ring through the pubic symphysis. Placement over the iliac crests is incorrect and can paradoxically open the pelvis further.

Question 565

Topic: 2. Trauma

What percentage of the articular surface must be involved in a dorsal PIP joint fracture dislocation for disruption of the collateral ligaments to occur?

. 20%
. 40%
. 60%
. 80%
. 100%

Correct Answer & Explanation

. 40%

Explanation

The percentage of articular surface involved differentiates a stable dorsal PIP joint fracture dislocation from an unstable one. It is believed that when the involved fracture fragment is less than 40% of the articular surface, the insertion site of the collateral ligaments is not disrupted and the joint is stable. If more than 40% of the articular surface is fractured, then the insertion of the collateral ligaments is involved and the joint will subsequently be unstable.

Question 566

Topic: 2. Trauma

A 22-year old right-hand dominant male college student consumes a large amount of alcohol and falls asleep for eleven hours with his right arm over a chair. When he awakens, he is unable to feel the dorsum of his hand and cannot extend his elbow, wrist, or the metacarpalphalangeal joints of his affected arm. Initial management should consist of

. Upper Extremity Angiography
. Observation
. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)
. Electromyography
. Emergent Nerve Exploration, with repair if necessary

Correct Answer & Explanation

. Observation

Explanation

Saturday night palsy is the term used for external compression of the radial nerve, and commonly occurs following the clinical scenario described above. The accepted treatment is observation, as Sunderland et al, described complete relief in all seven patients with Saturday night palsy after a period of observation without any adjunctive treatments. Although NSAIDs can be used if pain is a symptom or there is significant edema, these are not necessarily needed. Electromyography may be indicated if there is no improvement in symptoms after a three to six month period of observation. Emergent nerve exploration is indicated only for open fractures with a known radial nerve injury. There is no role for angiography in treatment of Saturday night palsy.

Question 567

Topic: 2. Trauma

A 7-year-old boy fell off the jungle gym and landed on his outstretched right arm sustaining a forearm fracture in both bones. The fracture requires reduction. He was given a combination of fentanyl and midazolam for sedation. At his current level of sedation, he is protecting his own airway. His oxygen saturation has dropped slightly to 92% but is stable. He does not display any awareness or discomfort when the fracture is being manipulated. How would you define his current level of sedation:

. Analgesia
. C onscious sedation
. Deep sedation
. General anesthesia
. Dissociative amnesia

Correct Answer & Explanation

. Deep sedation

Explanation

Deep sedation is the level where most fracture reductions are performed. Patients who are deeply sedated do not respond to verbal or noxious stimuli; they may display both a decreased ability to protect their airway and decreased respiratory drive. Analgesia is defined as affecting the sensation of pain, however, there is no change in overall awareness. Conscious sedation is defined as a lessening of awareness, with maintenance of protective reflexes. Patients will respond appropriately to commands and awaken to verbal stimuli. Patients do not respond to commands or noxious stimuli. With general anesthesia, patients will not respond to verbal or noxious stimuli. Additionally, they lose all of their respiratory drive and ability to protect their airway.

Question 568

Topic: 2. Trauma

A 14-year-old girl with a history of multiple food allergies and severe asthma was involved in a motor vehicle accident and sustained an isolated right femur fracture. Which of the following medications is the best choice to control her pain:

. Ketamine
. Morphine
. Methohexital
. Meperidine
. Midazolam

Correct Answer & Explanation

. Meperidine

Explanation

The goal in this patient is to provide safe, effective, and long-acting analgesia. Meperidine is recommended in this circumstance. It is an opioid that provides intermediate and long-term analgesia. Additionally, it does not cause the associated histamine release and bronchospasm that can occur in patients with asthma and atopia. Ketamine would provide short-term analgesia, but would also alter the level of consciousness. Morphine is well known for precipitating bronchospasm in patients with atopia and asthma. Therefore, it would not be the best choice in the scenario presented. Methohexital (a barbiturate) and midazolam (a benzodiazepine) both cause decreased awareness and have no analgesic properties.

Question 569

Topic: 2. Trauma

Which of the following choices is the best for sedating an otherwise healthy child for a fracture reduction:

. Morphine, diazepam
. Meperidine, midazolam
. Fentanyl, diazepam
. Demerol, phenergan, and thorazine
. Fentanyl, midazolam

Correct Answer & Explanation

. Fentanyl, midazolam

Explanation

The combination of fentanyl and midazolam is the closest we have to an ideal drug combination for conscious sedation. Both drugs have commercially available antagonists. Fentanyl and midazolam are both quick- onset and short-duration drugs. When using these two drugs together, there is a significant risk of respiratory depression. It is important to monitor patients closely.

Question 570

Topic: 2. Trauma

A 7-year-old child sustained a type 3 closed supracondylar fracture of the humerus 2 hours ago. Neurologic function is intact, but a pulse cannot be found by palpation or doppler. The hand is slightly cool. Your next step is to perform:

. Arteriogram of the extremity.
. Injection of lidocaine into the antecubital region
. An attempt at closed reduction of the fracture
. Open reduction of the fracture
. Vascular repair

Correct Answer & Explanation

. An attempt at closed reduction of the fracture

Explanation

Closed reduction should be carefully attempted at first, and often a tethered artery will be freed. If no pulse returns, open exploration is indicated if the hand remains cool. An arteriogram is rarely indicated because it is unlikely to yield additional information. Lidocaine may be instilled if there is spasm at the time of open reduction. Open reduction of the fracture is indicated only if closed reduction fails, or if the fracture is open. Vascular repair is not the first step; exploration and repair should be carried out only if the pulse does not return after an attempt at closed reduction.

Question 571

Topic: 2. Trauma
A 35-year-old male sustains a severe open tibia fracture with massive soft tissue stripping and exposed bone lacking periosteal coverage. What is the most appropriate Gustilo-Anderson classification and indicated soft tissue management?
. Type IIIA requiring a split-thickness skin graft
. Type IIIB requiring local or free flap coverage
. Type IIIC requiring immediate amputation
. Type IIIA requiring delayed primary closure
. Type IIIB requiring secondary intention healing

Correct Answer & Explanation

. Type IIIB requiring local or free flap coverage

Explanation

A Gustilo-Anderson Type IIIB fracture is characterized by extensive soft tissue loss with periosteal stripping and exposed bone. This requires complex soft tissue reconstruction, such as a rotational or free muscle flap.

Question 572

Topic: 2. Trauma

A 28-year-old male sustains a closed comminuted tibial shaft fracture and complains of pain out of proportion to the injury. Which intra-compartmental pressure measurement is the most reliable threshold for diagnosing acute compartment syndrome?

. Absolute pressure greater than 15 mmHg
. Absolute pressure greater than 20 mmHg
. Differential pressure (diastolic blood pressure minus compartment pressure) less than 30 mmHg
. Differential pressure (systolic blood pressure minus compartment pressure) less than 40 mmHg
. Absolute pressure greater than 25 mmHg

Correct Answer & Explanation

. Differential pressure (diastolic blood pressure minus compartment pressure) less than 30 mmHg

Explanation

The delta P (diastolic blood pressure minus intra-compartmental pressure) is the most reliable indicator of compartment syndrome. A delta P of less than 30 mmHg is the widely accepted threshold indicating the need for immediate fasciotomy.

Question 573

Topic: 2. Trauma

A 9-month-old non-ambulatory infant presents to the emergency department with a spiral fracture of the right femoral shaft. The parents state the child caught his leg in the crib slats. What is the most appropriate next step in management?

. Application of a Pavlik harness
. Immediate closed reduction and spica casting
. Flexible intramedullary nailing of the femur
. Mandatory skeletal survey and referral to Child Protective Services
. Open reduction and internal fixation with a compression plate

Correct Answer & Explanation

. Mandatory skeletal survey and referral to Child Protective Services

Explanation

In a non-ambulatory infant under 1 year of age, a femur fracture is highly suspicious for non-accidental trauma regardless of the fracture pattern. A complete skeletal survey and involvement of Child Protective Services are critical first steps.

Question 574

Topic: 2. Trauma
A 35-year-old male arrives in the trauma bay following a high-speed motorcycle collision. He has an anteroposterior compression type III (APC-III) pelvic ring injury. Despite application of a pelvic binder and massive transfusion protocols, he remains hemodynamically unstable. What is the most appropriate emergent intervention?
. Application of a supra-acetabular external fixator
. Preperitoneal pelvic packing and/or pelvic angioembolization
. Emergent open reduction and internal fixation of the symphysis pubis
. Exploratory laparotomy with bowel resection
. Retrograde urethrogram followed by Foley catheter placement

Correct Answer & Explanation

. Preperitoneal pelvic packing and/or pelvic angioembolization

Explanation

In a hemodynamically unstable patient with a mechanically stabilized pelvic fracture who fails to respond to fluid resuscitation, retroperitoneal arterial or venous hemorrhage is likely. Preperitoneal pelvic packing or angioembolization is the emergent treatment of choice.

Question 575

Topic: 2. Trauma

A 40-year-old male sustains a Schatzker II tibial plateau fracture. During surgical fixation, the surgeon decides to evaluate the articular reduction directly. Which of the following surgical approaches and techniques is most appropriate for this specific fracture pattern?

. Posteromedial approach with elevation of the pes anserinus
. Anterolateral approach with a submeniscal arthrotomy
. Direct posterior approach via the popliteal fossa
. Medial parapatellar approach with eversion of the patella
. Lateral approach with an osteotomy of the fibular head

Correct Answer & Explanation

. Anterolateral approach with a submeniscal arthrotomy

Explanation

A Schatzker II fracture is a split-depression fracture of the lateral tibial plateau. It is best managed via an anterolateral approach, often incorporating a submeniscal arthrotomy to directly visualize and elevate the depressed articular segments.

Question 576

Topic: 2. Trauma

A 32-year-old man sustains a closed midshaft tibia fracture. Twelve hours post-admission, he develops severe leg pain out of proportion to the injury. Intracompartmental pressure testing reveals an absolute pressure of 45 mmHg, and his diastolic blood pressure is 60 mmHg. What is the most appropriate next step in management?

. Elevate the leg above heart level and reassess in 2 hours
. Administer intravenous mannitol
. Emergent four-compartment fasciotomy
. Apply a long leg cast
. Perform an MRI of the lower extremity

Correct Answer & Explanation

. Emergent four-compartment fasciotomy

Explanation

Acute compartment syndrome is diagnosed when the Delta P (Diastolic BP minus Compartment Pressure) is less than 30 mmHg. In this patient, the Delta P is 15 mmHg (60 - 45), mandating an emergent four-compartment fasciotomy.

Question 577

Topic: 2. Trauma

A volar approach to the scaphoid is ideal in which of the following fractures:

. Proximal pole fractures
. Distal pole fractures
. C omminuted scaphoid fractures
. Avascular necrosis of the scaphoid proximal pole
. Scaphoid fracture with associated scapholunate ligament tear

Correct Answer & Explanation

. Distal pole fractures

Explanation

The volar approach to the scaphoid is optimal in distal pole fractures because it allows direct visualization of the fracture line and exact reduction and fixation. A volar approach is not recommended for fractures or avascular necrosis of the proximal pole, where dorsal screw placement is best. Scapholunate ligament tears are generally repaired from a dorsal approach because the ligament is stoutest dorsally.

Question 578

Topic: 2. Trauma
Which of the following two main soft tissue forces are disrupted by Bennett's fracture subluxation?
. Volar beak (anterior oblique) ligament and extensor pollicis longus
. Volar beak (anterior oblique) ligament and abductor pollicis longus
. Posterior oblique ligament and abductor pollicis brevis
. Dorsal radial ligament and flexor pollicis brevis
. Dorsal radial ligament and abductor pollicis brevis

Correct Answer & Explanation

. Volar beak (anterior oblique) ligament and abductor pollicis longus

Explanation

The volar, ulnar quadrant piece usually remains stationary due to the volar beak ligament. The thumb metacarpal base tends to sublux dorsoradially due to unopposed pull of the abductor pollicis longus and adductor pollicis. The intact volar beak ligament is usually the counterforce to these two muscles in the static situation. The extensor pollicis longus, flexor pollicis brevis, and abductor pollicis longus do not have significant involvement in the Bennett's fracture subluxation. Although the dorsal radial ligament is important for carpometacarpal stability, it is not the ligament attached to the fracture fragment.

Question 579

Topic: 2. Trauma
The greatest amount of step-off that is well-tolerated in a Bennett's fracture is:
. 0 mm
. 1 mm to 2 mm
. 2 mm to 3 mm
. 3 mm to 4 mm
. 4 mm to 5 mm

Correct Answer & Explanation

. 1 mm to 2 mm

Explanation

Studies by Livesley, Kjaer-Petersen, and others have shown that patients with fractures with more than a 1-mm step-off after reduction were more likely to develop arthritis at the thumb carpometacarpal joint. Although some studies have not shown functional outcome correlating with the presence of arthritis, Oosterbos and De Boer found that all their patients with fair and poor overall results had nonanatomic reductions. Although a cadaveric study by Cullen has shown that a 2-mm step-off may be acceptable, this contrasts with the clinical evidence currently available.

Question 580

Topic: 2. Trauma

When fracture step-off is greater than the accepted limits, which of the following complications is the most common:

. Arthritis
. Pain
. Decreased range of motion
. Decreased pinch strength
. All of the above

Correct Answer & Explanation

. All of the above

Explanation

Studies by Livesley, Kjaer-Petersen, and others have shown that patients with fractures with more than a 1-mm step-off after reduction were more likely to develop arthritis at the thumb carpometacarpal joint. Pain, decreased range of motion, and decreased pinch strength also correlated with these poor outcomes.

Test Yourself

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

On this Page