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Pelvic & Acetabular Trauma MCQs

Practice Set 7 of 35

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

Question 121

Topic: Pelvic & Acetabular Trauma

In the initial resuscitation of a hemodynamically unstable patient with an anteroposterior compression (APC) pelvic ring injury, a circumferential pelvic binder must be applied. What is the optimal anatomical landmark for the placement of the binder to effectively reduce pelvic volume?

. Bilateral iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Pubic symphysis
. Subtrochanteric femurs

Correct Answer & Explanation

. Greater trochanters

Explanation

To effectively reduce pelvic volume and stabilize the bleeding fracture, a circumferential pelvic binder must be centered directly over the greater trochanters. Misplacement over the iliac crests is less effective and may inadvertently widen the pelvic basin in certain unstable fracture patterns.

Question 122

Topic: Pelvic & Acetabular Trauma
A 45-year-old male arrives in the trauma bay with a pelvic binder in place after an anteroposterior compression (APC-III) injury. He remains hypotensive despite 2 liters of crystalloid and 2 units of packed RBCs. Focused assessment with sonography for trauma (FAST) is negative. What is the most appropriate next step in management?
. Perform an exploratory laparotomy
. Remove the pelvic binder to assess the skin
. Proceed to pelvic angiography for embolization or preperitoneal packing
. Apply a definitive anterior external fixator in the ER
. Administer broad-spectrum antibiotics and observe

Correct Answer & Explanation

. Proceed to pelvic angiography for embolization or preperitoneal packing

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and a negative FAST exam, the bleeding is likely from the retroperitoneal pelvic venous plexus or arterial branches. Emergent pelvic angiography for embolization or preperitoneal pelvic packing is indicated.

Question 123

Topic: Pelvic & Acetabular Trauma

On an AP pelvis radiograph of a patient with an acetabular fracture, the iliopectineal line is disrupted, but the ilioischial line remains intact. Which specific component of the acetabulum is most likely fractured?

. Anterior column
. Posterior column
. Posterior wall
. Transverse
. Both columns

Correct Answer & Explanation

. Anterior column

Explanation

The iliopectineal line represents the anterior column of the acetabulum on an AP radiograph. Disruption of this line with an intact ilioischial line (which represents the posterior column) is pathognomonic for an anterior column fracture.

Question 124

Topic: Pelvic & Acetabular Trauma
A 45-year-old male is crushed by heavy machinery and arrives hemodynamically unstable with a blood pressure of 75/40 mmHg. An anteroposterior pelvic radiograph reveals an anteroposterior compression (APC) Type III pelvic ring injury. A circumferential pelvic sheet or binder should be applied at which of the following anatomic levels to best reduce the pelvic volume?
. Iliac crests
. Greater trochanters
. Anterior superior iliac spines (ASIS)
. Pubic symphysis
. L5-S1 junction

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders must be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume. Placement over the iliac crests is incorrect and can paradoxically open the pelvis further in some fracture patterns.

Question 125

Topic: Pelvic & Acetabular Trauma

A 35-year-old trauma patient with an unstable pelvic ring injury requires the application of a pelvic binder to reduce pelvic volume and control hemorrhage. For maximum biomechanical effectiveness, over which anatomical landmark should the binder be centered?

. Anterior superior iliac spines (ASIS)
. Iliac crests
. Greater trochanters
. Pubic symphysis
. Sacral promontory

Correct Answer & Explanation

. Greater trochanters

Explanation

To effectively reduce pelvic volume and compress the bleeding surfaces of a disrupted pelvic ring, the pelvic binder must be centered over the greater trochanters. Placement over the iliac crests is incorrect and can paradoxically open the pelvic ring.

Question 126

Topic: Pelvic & Acetabular Trauma

A 12-year-old patient is scheduled for a Salter osteotomy for developmental dysplasia of the hip (DDH) via the Smith-Petersen approach. During the deep muscular dissection, the surgeon needs to reflect the rectus femoris muscle to expose the anterior hip capsule. From which two distinct anatomical locations do the direct and indirect heads of the rectus femoris originate?

. A. Direct head from the anterior inferior iliac spine (AIIS); Indirect head from the iliac crest.
. B. Direct head from the anterior superior iliac spine (ASIS); Indirect head from the anterior inferior iliac spine (AIIS).
. C. Direct head from the pubic symphysis; Indirect head from the ischial tuberosity.
. D. Direct head from the greater trochanter; Indirect head from the lesser trochanter.
. E. Direct head from the iliac crest; Indirect head from the ASIS.

Correct Answer & Explanation

. B. Direct head from the anterior superior iliac spine (ASIS); Indirect head from the anterior inferior iliac spine (AIIS).

Explanation

Correct Answer: BThe rectus femoris muscle, a key structure encountered and reflected during the deep dissection of the Smith-Petersen approach, originates via two distinct heads: the direct head originates from the Anterior Superior Iliac Spine (ASIS), and the indirect (reflected) head originates from a groove superior to the acetabulum, specifically the Anterior Inferior Iliac Spine (AIIS). Both heads converge to form a single tendon.Why other options are incorrect:A. Direct head from the anterior inferior iliac spine (AIIS); Indirect head from the iliac crest:This is incorrect. The direct head is from the ASIS, and the indirect head is from the AIIS. The iliac crest is the origin for muscles like the TFL and gluteus medius, but not the rectus femoris heads.C. Direct head from the pubic symphysis; Indirect head from the ischial tuberosity:These are origins for other hip and thigh muscles (e.g., adductors, hamstrings), not the rectus femoris.D. Direct head from the greater trochanter; Indirect head from the lesser trochanter:The greater and lesser trochanters are insertion points for various hip muscles (e.g., gluteus medius/minimus, iliopsoas), not origins for the rectus femoris.E. Direct head from the iliac crest; Indirect head from the ASIS:This is incorrect. The direct head is from the ASIS, and the indirect head is from the AIIS. The iliac crest is not an origin for the rectus femoris.

Question 127

Topic: Pelvic & Acetabular Trauma

A 35-year-old male sustains an anteroposterior compression type II (APC-II) pelvic ring injury. Which of the following ligaments is torn in this specific injury pattern, distinguishing it from an APC-I injury?

. Sacrospinous, sacrotuberous, and anterior sacroiliac ligaments
. Symphyseal ligaments only
. Posterior sacroiliac ligaments
. Iliolumbar ligaments
. Anterior and posterior sacroiliac ligaments

Correct Answer & Explanation

. Sacrospinous, sacrotuberous, and anterior sacroiliac ligaments

Explanation

In an APC-II injury, the pubic diastasis is greater than 2.5 cm, and the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments are disrupted. The posterior sacroiliac ligaments remain intact, providing vertical stability.

Question 128

Topic: Pelvic & Acetabular Trauma
A 28-year-old male is brought to the trauma bay after a motorcycle accident. He is hemodynamically unstable with a blood pressure of 80/40 mmHg. FAST exam is negative. Pelvic radiograph shows an anteroposterior compression type III (APC III) injury. A pelvic binder is applied, but the patient remains persistently hypotensive despite aggressive fluid resuscitation. What is the most appropriate next step in management?
. Application of a pelvic external fixator
. Immediate exploratory laparotomy
. Bilateral internal iliac artery embolization
. Pelvic angiography or preperitoneal pelvic packing
. Emergent symphyseal plating

Correct Answer & Explanation

. Pelvic angiography or preperitoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a mechanically unstable pelvic ring injury and a negative FAST exam, the bleeding is presumed to be retroperitoneal. After applying a pelvic binder, persistent instability requires either angiography with embolization or preperitoneal pelvic packing based on institutional protocols.

Question 129

Topic: Pelvic & Acetabular Trauma

A 35-year-old male is brought to the ED after a high-speed motorcycle collision. He is hypotensive with a systolic BP of 70 mmHg. Pelvic radiograph shows a completely disrupted pubic symphysis with severe widening and disruption of the posterior sacroiliac ligaments bilaterally. After initiating massive transfusion, what is the most appropriate next step in orthopedic management?

. Immediate open reduction and internal fixation of the symphysis pubis
. Application of a pelvic binder centered over the greater trochanters
. Pelvic angiography and embolization
. Retrograde urethrogram
. Application of a pelvic binder centered over the iliac crests

Correct Answer & Explanation

. Application of a pelvic binder centered over the greater trochanters

Explanation

In a hemodynamically unstable patient with an anteroposterior compression (APC) pelvic ring injury, the initial step is applying a pelvic binder over the greater trochanters. This reduces pelvic volume and helps tamponade venous bleeding before considering angiography or surgery.

Question 130

Topic: Pelvic & Acetabular Trauma
A 35-year-old male is involved in a high-speed motor vehicle collision. Pelvic radiographs show a widened symphysis pubis of 3.5 cm. CT scan reveals disruption of the anterior sacroiliac ligaments but intact posterior sacroiliac ligaments. What is the correct Young-Burgess classification of this injury?
. Anteroposterior Compression (APC) I
. Anteroposterior Compression (APC) II
. Anteroposterior Compression (APC) III
. Lateral Compression (LC) I
. Lateral Compression (LC) II

Correct Answer & Explanation

. Anteroposterior Compression (APC) II

Explanation

An APC II injury is characterized by a symphyseal diastasis greater than 2.5 cm and disruption of the anterior sacroiliac ligaments. The posterior sacroiliac ligaments remain intact, providing vertical stability but rotational instability.

Question 131

Topic: Pelvic & Acetabular Trauma
A patient presents after a severe crush injury with an anteroposterior compression (APC) Type III pelvic ring injury. What primary anatomical structure's complete disruption differentiates an APC III from an APC II injury?
. Anterior sacroiliac ligaments
. Sacrotuberous ligaments
. Sacrospinous ligaments
. Posterior sacroiliac ligaments
. Symphysis pubis

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

In the Young-Burgess classification, APC II involves disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments but leaves the posterior sacroiliac ligaments intact. APC III involves complete disruption of the posterior sacroiliac ligaments, resulting in complete global pelvic instability.

Question 132

Topic: Pelvic & Acetabular Trauma

A 42-year-old female is brought in after a rollover MVC. She is hemodynamically unstable. A pelvic radiograph shows a widened pubic symphysis of 4 cm and disrupted posterior sacroiliac ligaments. Where is the most anatomically correct placement for a pelvic circumferential compression device?

. Level of the iliac crests
. Level of the anterior superior iliac spines
. Level of the greater trochanters
. Level of the mid-femoral shaft
. Directly over the pubic symphysis

Correct Answer & Explanation

. Level of the greater trochanters

Explanation

Pelvic binders should be placed at the level of the greater trochanters to effectively reduce pelvic volume by applying appropriate compressive forces across the pelvic ring. Placement higher on the iliac crests can cause paradoxical opening or inadequate reduction.

Question 133

Topic: Pelvic & Acetabular Trauma

A 25-year-old male unrestrained passenger is involved in a head-on motor vehicle collision. His knees strike the dashboard. In the emergency department, his right leg is severely painful and completely immobile. Which of the following postures is classic for an unreduced posterior hip dislocation?

. Hip flexed, abducted, and externally rotated
. Hip flexed, adducted, and internally rotated
. Hip extended, abducted, and externally rotated
. Hip extended, adducted, and internally rotated
. Leg is simply shortened and externally rotated without flexion

Correct Answer & Explanation

. Hip flexed, adducted, and internally rotated

Explanation

A posterior hip dislocation typically presents with the affected limb shortened, flexed, adducted, and internally rotated. This occurs because the femoral head rests posterior and superior to the acetabulum, putting tension on the anterior hip capsule and Y-ligament.

Question 134

Topic: Pelvic & Acetabular Trauma

A 35-year-old male presents with a hypotensive (BP 75/40 mmHg) pelvic ring injury after a crush injury. The FAST exam is negative. A pelvic binder is applied, but he remains persistently hypotensive (BP 80/45 mmHg) after 2 liters of crystalloid. The institution lacks immediate interventional radiology capabilities. What is the most appropriate next step in management?

. Preperitoneal pelvic packing
. Exploratory laparotomy
. Placement of a REBOA catheter by general surgery
. CT abdomen and pelvis with IV contrast
. Immediate transfer to a Level 1 trauma center

Correct Answer & Explanation

. Preperitoneal pelvic packing

Explanation

In a hemodynamically unstable patient with a pelvic ring injury and negative FAST who fails to respond to a pelvic binder and volume resuscitation, retroperitoneal venous or cancellous bone bleeding is likely. Preperitoneal pelvic packing is the most appropriate and immediate lifesaving intervention, especially when angiography is unavailable.

Question 135

Topic: Pelvic & Acetabular Trauma
A 28-year-old female presents after a motorcycle accident with a mechanically unstable pelvic ring injury classified as a Young-Burgess Lateral Compression Type III. Her blood pressure is 90/60 mmHg, and heart rate is 120 bpm, despite initial fluid resuscitation. What is the most appropriate next step in her management?
. Immediate application of a pelvic external fixator.
. Formal angiography with embolization.
. CT scan of the pelvis with IV contrast.
. Application of a pelvic binder and continued resuscitation.
. Direct transport to the operating room for diagnostic laparotomy.

Correct Answer & Explanation

. Application of a pelvic binder and continued resuscitation.

Explanation

A Young-Burgess Lateral Compression Type III (LC-III) pelvic ring injury indicates a significant pelvic disruption, typically involving a sacral fracture or sacroiliac joint disruption, leading to posterior instability and potential for severe retroperitoneal hemorrhage. In a hypotensive patient with a suspected pelvic hemorrhage, the immediate priority is to stabilize the pelvis and control bleeding. Application of a pelvic binder (or sheet) provides temporary external compression, reducing the pelvic volume and potentially tamponading venous bleeding, which accounts for the majority of hemorrhage in pelvic fractures. This should be combined with continued aggressive fluid resuscitation and transfusion.

Question 136

Topic: Pelvic & Acetabular Trauma
A 28-year-old patient arrives in the trauma bay hemodynamically unstable following a motorcycle collision. Pelvic radiographs demonstrate an "open book" anterior-posterior compression (APC-III) pelvic ring injury. A pelvic binder should be placed at which anatomic level?
. Above the umbilicus
. Over the iliac crests
. Mid-thigh
. Centered over the greater trochanters
. Over the symphysis pubis and L5

Correct Answer & Explanation

. Centered over the greater trochanters

Explanation

A pelvic binder provides the most effective mechanical advantage for reducing pelvic volume and controlling hemorrhage when it is centered over the greater trochanters, accurately targeting the pubic symphysis.

Question 137

Topic: Pelvic & Acetabular Trauma
A trauma patient arrives hemodynamically unstable with a mechanically unstable anteroposterior compression (APC) type III pelvic ring injury. A circumferential pelvic binder is applied. What is the primary mechanism by which the binder achieves hemostasis?
. Direct compression of the common iliac artery
. Direct compression of the presacral venous plexus
. Reduction of pelvic volume allowing for a tamponade effect of venous bleeding
. Occlusion of the internal pudendal artery
. Immediate stimulation of the intrinsic coagulation cascade

Correct Answer & Explanation

. Reduction of pelvic volume allowing for a tamponade effect of venous bleeding

Explanation

Pelvic binders provide acute stabilization and reduce pelvic volume. This apposes cancellous bone surfaces and creates a tamponade effect that is primarily effective in slowing venous and cancellous bone bleeding.

Question 138

Topic: Pelvic & Acetabular Trauma
A trauma patient arrives hypotensive with an unstable pelvis. Radiographs show complete diastasis of the pubic symphysis and profound widening of both sacroiliac joints. Based on the Young-Burgess classification, an anterior-posterior compression (APC) type III injury is diagnosed. Which of the following ligaments must be disrupted in an APC III injury?
. Sacrospinous ligaments only
. Anterior sacroiliac ligaments only
. Sacrotuberous ligaments only
. Anterior and posterior sacroiliac ligaments
. Iliolumbar ligaments only

Correct Answer & Explanation

. Anterior and posterior sacroiliac ligaments

Explanation

An APC III pelvic ring injury involves complete disruption of both the anterior ring (symphysis) and the posterior ring. This requires tearing of both the anterior and the robust posterior sacroiliac ligaments, leading to complete rotational and vertical instability.

Question 139

Topic: Pelvic & Acetabular Trauma
In the initial trauma bay resuscitation of a hemodynamically unstable patient with an anterior-posterior compression (APC-III) pelvic ring injury, what is the optimal anatomical landmark for the correct placement of a pelvic circumferential compression device (binder)?
. At the level of the superior iliac crests
. Centered directly over the greater trochanters
. Midway between the umbilicus and the pubic symphysis
. Just proximal to the anterior superior iliac spines (ASIS)
. At the level of the inferior pubic rami

Correct Answer & Explanation

. Centered directly over the greater trochanters

Explanation

Pelvic binders must be centered precisely over the greater trochanters to effectively compress the pelvic ring and reduce intrapelvic volume. Placement too proximally over the iliac crests is biomechanically inferior and can paradoxically open the true pelvis further.

Question 140

Topic: Pelvic & Acetabular Trauma

A 45-year-old male presents after a motorcycle collision with an anteroposterior compression (APC) type II pelvic ring injury. His hemodynamics are stable. What is the primary anatomic indication for surgical fixation of the anterior ring in this specific injury pattern?

. Symphyseal diastasis greater than 2.5 cm
. Presence of a concurrent Denis zone 1 sacral fracture
. Prevention of long-term erectile dysfunction
. Presence of a posterior urethral tear
. Associated L5 nerve root injury

Correct Answer & Explanation

. Symphyseal diastasis greater than 2.5 cm

Explanation

A symphyseal diastasis > 2.5 cm indicates disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments, leading to rotational instability. Surgical fixation is indicated to restore pelvic ring stability and anatomy.

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