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2. Trauma MCQs

Practice Set 282 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 5621

Topic: Pelvic & Acetabular Trauma
A 22-year-old male is brought to the trauma bay after a motorcycle accident. Pelvic radiographs demonstrate significant widening of the pubic symphysis, indicative of an anteroposterior compression (APC) injury. To classify this as an APC Type III injury (Young-Burgess classification), which of the following combinations of posterior pelvic ring ligaments must be completely disrupted?
. Anterior sacroiliac ligaments only
. Sacrospinous and sacrotuberous ligaments only
. Anterior sacroiliac, sacrospinous, and sacrotuberous ligaments (posterior sacroiliac ligaments intact)
. Anterior sacroiliac, posterior sacroiliac, sacrospinous, and sacrotuberous ligaments
. Posterior sacroiliac ligaments only

Correct Answer & Explanation

. Anterior sacroiliac, posterior sacroiliac, sacrospinous, and sacrotuberous ligaments

Explanation

In the Young-Burgess classification, APC I involves symphysis widening <2.5 cm with intact posterior ligaments. APC II involves symphysis widening >2.5 cm, disruption of the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments, but the critical posterior sacroiliac (SI) ligaments remain intact (rotationally unstable, vertically stable). APC III indicates complete disruption of the anterior SI, sacrospinous, sacrotuberous, AND the posterior SI ligaments, resulting in a completely unstable hemipelvis (both rotationally and vertically).

Question 5622

Topic: 2. Trauma

A 45-year-old male sustains a Schatzker IV tibial plateau fracture with a large posteromedial shear fragment.

He is scheduled for open reduction and internal fixation. A posteromedial surgical approach is planned. To safely access the fracture fragment, the surgical interval is developed between which of the following structures?

. Medial head of the gastrocnemius and the pes anserinus
. Semimembranosus and semitendinosus
. Popliteus and soleus
. Tibialis posterior and flexor digitorum longus
. Anterior tibialis and extensor hallucis longus

Correct Answer & Explanation

. Medial head of the gastrocnemius and the pes anserinus

Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the medial head of the gastrocnemius (which is retracted laterally/posteriorly) and the pes anserinus tendons (which are retracted anteriorly/medially). This provides excellent direct access to posteromedial shear fragments for buttress plating.

Question 5623

Topic: Pelvic & Acetabular Trauma
A 28-year-old motorcyclist is involved in a high-speed collision and sustains an anterior-posterior compression (APC) type III pelvic ring injury. According to the Young-Burgess classification, this injury pattern is characterized by the complete disruption of the symphysis pubis and which of the following posterior ligamentous complexes?
. Anterior sacroiliac, sacrospinous, and sacrotuberous ligaments only
. Anterior sacroiliac, sacrospinous, sacrotuberous, and posterior sacroiliac ligaments
. Posterior sacroiliac ligaments only
. Iliolumbar ligaments only
. Sacrospinous and sacrotuberous ligaments only

Correct Answer & Explanation

. Anterior sacroiliac, sacrospinous, sacrotuberous, and posterior sacroiliac ligaments

Explanation

An APC III pelvic injury involves complete disruption of both the anterior and posterior pelvic rings. This includes the symphysis pubis anteriorly, and all of the posterior ligamentous structures: the anterior sacroiliac ligaments, the pelvic floor ligaments (sacrospinous and sacrotuberous), and the strong posterior sacroiliac ligaments, leading to complete global instability of the hemipelvis.

Question 5624

Topic: 2. Trauma

A 26-year-old male is admitted after sustaining a severely comminuted, closed fracture of the tibial shaft. He develops escalating leg pain out of proportion to his injury. Examination reveals tense compartments and pain with passive stretch of the toes. Intracompartmental pressure testing is performed. Which of the following pressure measurements (Delta P = Diastolic Blood Pressure - Compartment Pressure) is widely considered the absolute indication for emergent fasciotomy?

. Delta P greater than 45 mmHg
. Delta P less than 30 mmHg
. Absolute compartment pressure greater than 15 mmHg
. Absolute compartment pressure greater than 20 mmHg
. Delta P less than 10 mmHg

Correct Answer & Explanation

. Delta P less than 30 mmHg

Explanation

The diagnosis of acute compartment syndrome is primarily clinical, but when objective measurements are needed, the 'Delta P' is used. A Delta P (diastolic blood pressure minus intracompartmental pressure) of less than 30 mmHg indicates inadequate tissue perfusion and is a universally accepted absolute indication for emergent fasciotomy.

Question 5625

Topic: 2. Trauma

A 45-year-old male sustains a complex tibial plateau fracture involving a displaced posteromedial fragment. The surgeon elects to use a posteromedial approach for open reduction and internal fixation. This approach utilizes an interval between which of the following structures?

. Medial head of the gastrocnemius and the soleus
. Medial head of the gastrocnemius and the pes anserinus
. Semimembranosus and semitendinosus
. Popliteus and medial head of the gastrocnemius
. Tibialis posterior and flexor digitorum longus

Correct Answer & Explanation

. Medial head of the gastrocnemius and the pes anserinus

Explanation

The posteromedial approach to the proximal tibia is the standard approach for addressing posteromedial shear fragments in tibial plateau fractures. The surgical interval exploits the space between the medial head of the gastrocnemius (which is retracted laterally) and the pes anserinus tendons (which are retracted medially and anteriorly).

Question 5626

Topic: 2. Trauma

Bone morphogenetic proteins (BMPs) are members of the TGF-beta superfamily. Recombinant human BMP-2 (rhBMP-2) has been approved by the FDA for specific clinical applications. Which of the following is an FDA-approved indication for the use of rhBMP-2?

. Acute open tibial shaft fractures
. Recalcitrant nonunion of the humeral shaft
. Posterolateral lumbar fusion
. Treatment of unicameral bone cysts
. Acute closed femoral shaft fractures

Correct Answer & Explanation

. Acute open tibial shaft fractures

Explanation

rhBMP-2 (Infuse) is FDA-approved for the treatment of acute, open tibial shaft fractures stabilized with an intramedullary nail within 14 days of injury, as well as for anterior lumbar interbody fusion (ALIF). Recombinant human BMP-7 (OP-1) was historically approved for long bone nonunions and revision posterolateral lumbar fusion, though its availability has changed.

Question 5627

Topic: 2. Trauma

A 24-year-old man falls onto an outstretched hand and sustains an acute, minimally displaced fracture of the proximal pole of the scaphoid. Because of the specific vascular anatomy of the scaphoid, which of the following is the most widely recommended treatment for this injury?

. Short arm thumb spica cast for 6 weeks
. Long arm thumb spica cast for 12 weeks
. Percutaneous or open screw fixation
. Proximal row carpectomy
. Scaphoid excision and four-corner fusion

Correct Answer & Explanation

. Percutaneous or open screw fixation

Explanation

The blood supply to the scaphoid enters distally via branches of the radial artery and flows retrograde to the proximal pole. Because of this tenuous vascular supply, proximal pole fractures have a very high rate of nonunion and avascular necrosis. Operative fixation (percutaneous or open) is recommended even for non-displaced proximal pole fractures to optimize the biomechanical environment for healing.

Question 5628

Topic: 2. Trauma

A 35-year-old male sustains a severe pelvic injury in an MVA. A spur sign, which is pathognomonic for a both-column acetabular fracture, is identified.

This sign is best visualized on which of the following radiographic views?

. AP pelvis
. Iliac oblique
. Obturator oblique
. Inlet view
. Outlet view

Correct Answer & Explanation

. Obturator oblique

Explanation

The spur sign represents the inferior portion of the intact superior ilium that has been left behind when the articular segment is displaced medially. It is pathognomonic for a both-column fracture of the acetabulum and is best visualized on the obturator oblique radiograph of the Judet series.

Question 5629

Topic: 2. Trauma

During evaluation of an ankle fracture, a syndesmotic injury is suspected.

On standard mortise radiographs of a normal ankle, the tibiofibular clear space should measure:

. Less than 2 mm
. Less than 4 mm
. Less than 6 mm
. Greater than 6 mm
. Less than 10 mm

Correct Answer & Explanation

. Less than 6 mm

Explanation

The tibiofibular clear space is measured 1 cm proximal to the tibial plafond. On both AP and mortise views, it should be less than 6 mm in a normal ankle. A measurement greater than 6 mm suggests a syndesmotic injury. Tibiofibular overlap should be >1 mm on the mortise view.

Question 5630

Topic: 2. Trauma

A 42-year-old male presents to the trauma bay following a high-speed motorcycle collision. He is diagnosed with a closed extra-articular scapular body fracture. According to current literature, which of the following is considered an indication for operative management of this fracture?

. Medial displacement of the glenoid fragment of 5 mm
. Angular deformity of the scapular body of 15 degrees
. A glenopolar angle of 35 degrees
. An associated undisplaced middle-third clavicle fracture
. Medial displacement of the glenoid fragment greater than 20 mm

Correct Answer & Explanation

. Medial displacement of the glenoid fragment greater than 20 mm

Explanation

Indications for operative fixation of extra-articular scapular fractures include severe medialization of the glenoid fragment (typically >20 mm, though some suggest >10 mm coupled with other factors), significant angular deformity (>45 degrees), or a glenopolar angle < 22 degrees. An undisplaced clavicle fracture (forming an undisplaced floating shoulder) is generally managed non-operatively. Medialization of >20 mm represents significant displacement that alters the resting length of the rotator cuff and periscapular musculature, warranting fixation.

Question 5631

Topic: Pelvic & Acetabular Trauma
A 28-year-old male sustains a pelvic ring injury after a fall from height. Radiographs and CT show a symphyseal diastasis of 3.5 cm. The anterior sacroiliac (SI) ligaments, sacrotuberous, and sacrospinous ligaments are disrupted, but the posterior SI ligaments remain intact. Based on the Young-Burgess classification, what is the correct diagnosis?
. Anteroposterior Compression I (APC I)
. Anteroposterior Compression II (APC II)
. Anteroposterior Compression III (APC III)
. Lateral Compression II (LC II)
. Lateral Compression III (LC III)

Correct Answer & Explanation

. Anteroposterior Compression II (APC II)

Explanation

The Young-Burgess classification describes the mechanism of injury for pelvic fractures. Anteroposterior Compression II (APC II) injuries are characterized by symphyseal diastasis > 2.5 cm with tearing of the anterior SI ligaments, sacrotuberous, and sacrospinous ligaments. Crucially, the posterior SI ligaments are intact, meaning the hemipelvis is rotationally unstable but vertically stable. APC III involves complete disruption of both anterior and posterior SI ligaments, resulting in both rotational and vertical instability.

Question 5632

Topic: 2. Trauma
A 25-year-old male sustains a comminuted tibia fracture and is treated with an intramedullary nail. Twelve hours postoperatively, he complains of severe, unrelenting leg pain out of proportion to the injury, unrelieved by IV opioids. He has pain with passive stretch of his great toe. Compartment pressures are measured. Which of the following parameters provides the most reliable indication for emergent four-compartment fasciotomy?
. Absolute anterior compartment pressure > 20 mmHg
. Absolute anterior compartment pressure > 30 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Mean arterial pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 30 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

The clinical diagnosis of acute compartment syndrome requires a high index of suspicion, with pain out of proportion and pain with passive stretch being early signs. When utilizing compartment pressure monitoring, the delta pressure (ΔP) is the most accurate diagnostic threshold. A ΔP (Diastolic Blood Pressure minus Absolute Compartment Pressure) of less than 30 mmHg is the widely accepted criteria for surgical intervention (fasciotomy). Relying on an absolute pressure > 30 mmHg can lead to unnecessary fasciotomies, especially in hypertensive patients.

Question 5633

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the trauma bay following a high-speed motorcycle crash. His heart rate is 125 bpm, and his blood pressure is 80/50 mmHg. An anteroposterior radiograph of the pelvis reveals a widened pubic symphysis (>2.5 cm) and significant widening of the bilateral sacroiliac joints. A pelvic binder is appropriately applied, and he receives 2 units of uncrossmatched blood. A FAST exam is negative. He remains hemodynamically unstable. Which of the following is the most appropriate next step in management?
. Preperitoneal pelvic packing
. Retrograde urethrogram
. Application of a second pelvic binder
. Exploratory laparotomy
. Immediate open reduction internal fixation of the anterior ring

Correct Answer & Explanation

. Preperitoneal pelvic packing

Explanation

This patient has an Anteroposterior Compression Type III (APC III) pelvic ring injury and is in hemorrhagic shock. In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST (ruling out massive intra-abdominal hemorrhage), the source of bleeding is presumed to be the pelvis (often venous or cancellous bone, though arterial bleeding can occur). Preperitoneal pelvic packing or angioembolization (depending on institutional protocol and immediate availability) are the appropriate next steps after mechanical stabilization with a binder. Exploratory laparotomy is incorrect as the FAST is negative.

Question 5634

Topic: 2. Trauma
A 42-year-old male presents with severe knee pain after falling off a ladder. An AP radiograph of the knee reveals a depressed fracture fragment in the lateral articular surface along with an oblique fracture line exiting the lateral metaphysis. Which of the following Schatzker classifications accurately describes this fracture, and what is the most commonly associated intra-articular soft tissue injury?
. Schatzker I; Medial meniscus
. Schatzker II; Lateral meniscus
. Schatzker III; Anterior cruciate ligament
. Schatzker IV; Lateral meniscus
. Schatzker V; Posterior cruciate ligament

Correct Answer & Explanation

. Schatzker II; Lateral meniscus

Explanation

A split-depression fracture of the lateral tibial plateau is classified as a Schatzker II fracture. This is the most common pattern of tibial plateau fracture. It is highly associated with meniscal injuries, specifically lateral meniscus tears, which occur in approximately 50-70% of cases and often require simultaneous repair or partial meniscectomy during ORIF.

Question 5635

Topic: 2. Trauma

A 32-year-old man sustains a closed fracture of the distal third of his humeral shaft, presenting with an inability to actively extend his wrist and digits. He undergoes open reduction and internal fixation using a posterior triceps-splitting approach. Which of the following accurately describes the relationship of the radial nerve to the humerus and intermuscular septum at the level of the distal third of the humeral shaft?

. It runs distally in the posterior compartment down to the lateral epicondyle
. It pierces the lateral intermuscular septum from posterior to anterior approximately 10 cm proximal to the radiocapitellar joint
. It crosses posterior to the medial epicondyle before piercing the medial intermuscular septum
. It enters the anterior compartment 2 cm proximal to the lateral epicondyle
. It travels superficially over the brachialis muscle throughout its entire course in the arm

Correct Answer & Explanation

. It pierces the lateral intermuscular septum from posterior to anterior approximately 10 cm proximal to the radiocapitellar joint

Explanation

The radial nerve spirals around the posterior humerus in the spiral groove and pieces the lateral intermuscular septum from posterior to anterior approximately 10 cm (range 7.5 to 12 cm) proximal to the radiocapitellar joint to enter the anterior compartment. This anatomical landmark is critical when performing a posterior approach to the humerus or when treating distal third humeral shaft fractures (Holstein-Lewis fractures).

Question 5636

Topic: Pelvic & Acetabular Trauma
A hemodynamically unstable 42-year-old male is brought to the trauma bay after a motorcycle crash. Pelvic radiographs demonstrate an APC-III pelvic ring injury ('open book' pelvis). A pelvic binder is immediately applied by the trauma team. Which of the following statements regarding the application and function of a pelvic binder is most accurate?
. It must be centered exactly over the greater trochanters to effectively close the pelvic ring
. It primarily achieves hemostasis by directly compressing bleeding from the superior gluteal artery
. It is absolutely contraindicated if a concurrent extraperitoneal bladder rupture is identified
. It should be applied tightly over the iliac crests to maximize anterior compression
. It works primarily by tamponading arterial bleeding in the presacral space

Correct Answer & Explanation

. It must be centered exactly over the greater trochanters to effectively close the pelvic ring

Explanation

To be effective in reducing pelvic volume and closing an open-book pelvic injury, a pelvic binder (or sheet) must be centered low, directly over the greater trochanters. Positioning it too high over the iliac crests can actually worsen the deformity by acting as a fulcrum. Its primary mechanism of action is reducing pelvic volume to encourage tamponade of the massive venous plexus bleeding, not arterial bleeding.

Question 5637

Topic: 2. Trauma

A 27-year-old man sustains a closed midshaft tibia fracture treated with intramedullary nailing. Six hours postoperatively, he develops severe, out-of-proportion leg pain and severe pain with passive stretch of his toes. Compartment pressure monitoring reveals an anterior compartment pressure of 45 mmHg. The decision is made to perform a standard four-compartment fasciotomy of the leg via a dual-incision technique. During the lateral incision, which anatomical structure is utilized as the key landmark to identify and separate the anterior and lateral compartments?

. Anterior intermuscular septum
. Posterior intermuscular septum
. Transverse intermuscular septum
. Interosseous membrane
. Superficial peroneal nerve

Correct Answer & Explanation

. Anterior intermuscular septum

Explanation

In the standard two-incision four-compartment fasciotomy of the lower leg, the lateral (or anterolateral) incision is made halfway between the tibial crest and the fibular shaft. The key fascial landmark identified through this incision is the anterior intermuscular septum. Fasciotomies are made anterior to this septum to release the anterior compartment, and posterior to it to release the lateral compartment.

Question 5638

Topic: Pelvic & Acetabular Trauma
A 35-year-old male presents after a high-speed motorcycle crash. Pelvic radiographs reveal symphysis pubis widening of 3.5 cm and widening of the anterior sacroiliac joints bilaterally, with intact posterior SI ligaments. What is the most common anatomic source of life-threatening hemorrhage in this specific injury pattern?
. Superior gluteal artery
. Internal pudendal artery
. Presacral venous plexus
. Cancellous bone of the fracture surfaces
. Obturator artery

Correct Answer & Explanation

. Presacral venous plexus

Explanation

The patient has an Anterior-Posterior Compression (APC) Type II pelvic ring injury. In pelvic trauma, roughly 80-90% of life-threatening hemorrhage is venous in origin, most commonly from the presacral and prevesical venous plexuses. While arterial bleeding (e.g., superior gluteal, internal pudendal) can occur and is often more rapidly fatal if present (particularly in severe APC III or highly displaced vertical shear/lateral compression patterns), the overall most common source of severe bleeding across pelvic ring disruptions is the venous plexus.

Question 5639

Topic: 2. Trauma

A 28-year-old male sustains a high-energy closed tibial shaft fracture. Two hours post-admission, he complains of worsening, unrelenting pain out of proportion to his injury. His diastolic blood pressure is 80 mmHg and mean arterial pressure is 95 mmHg. Compartment pressures are measured. What measurement threshold is the most widely accepted absolute indication for a four-compartment fasciotomy?

. Absolute compartment pressure > 20 mmHg
. Absolute compartment pressure > 45 mmHg
. Delta P (Diastolic BP - Compartment Pressure) < 30 mmHg
. Delta P (Mean Arterial Pressure - Compartment Pressure) < 40 mmHg
. Delta P (Systolic BP - Compartment Pressure) < 20 mmHg

Correct Answer & Explanation

. Delta P (Diastolic BP - Compartment Pressure) < 30 mmHg

Explanation

The diagnosis of acute compartment syndrome is primarily clinical, but when measurements are used, a Delta P (Diastolic Blood Pressure minus absolute Compartment Pressure) of less than 30 mmHg is the most reliable threshold for indicating fasciotomy. Absolute pressure thresholds are less reliable because tissue perfusion depends on the driving gradient between the diastolic pressure and the local tissue pressure.

Question 5640

Topic: 2. Trauma

A 34-year-old male presents after a high-speed motorcycle collision. Radiographs demonstrate a displaced scapular body fracture.

Which of the following associated injuries is statistically most common in this clinical setting?

. Rib fractures
. Closed head injury
. Brachial plexus palsy
. Pneumothorax
. Subclavian artery injury

Correct Answer & Explanation

. Rib fractures

Explanation

Rib fractures are the most common associated injury with scapula fractures, seen in over 50% of cases. Because a massive amount of energy is required to fracture the well-protected scapula, associated injuries to the thorax, including pulmonary contusion and pneumothorax, are highly prevalent, but rib fractures remain the most frequent.

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