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2. Trauma MCQs

Practice Set 430 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 8581

Topic: 2. Trauma

A 28-year-old man sustains a Monteggia equivalent fracture-dislocation and requires open reduction and internal fixation of the proximal radius. A volar (Henry) approach to the proximal radius is utilized. During deep dissection, the supinator muscle is identified. To safely expose the proximal radius and prevent injury to the posterior interosseous nerve (PIN), the forearm should be placed in which position, and what is the relationship of the PIN to the supinator?

. Pronation; the PIN runs superficial to the supinator muscle
. Supination; the PIN runs between the two heads of the supinator muscle
. Pronation; the PIN runs between the two heads of the supinator muscle
. Supination; the PIN runs deep to the supinator muscle
. Neutral; the PIN runs medial to the supinator muscle

Correct Answer & Explanation

. Supination; the PIN runs between the two heads of the supinator muscle

Explanation

When utilizing the volar (Henry) approach to the proximal radius, the forearm should be supinated to displace the posterior interosseous nerve (PIN) radially and away from the surgical field. The PIN passes between the superficial and deep heads of the supinator muscle. Pronation brings the nerve ulnarly into the operative field, increasing the risk of iatrogenic transection.

Question 8582

Topic: 2. Trauma

A 40-year-old male develops acute compartment syndrome of the lower leg following a tibial plateau fracture. The surgeon proceeds with a two-incision four-compartment fasciotomy. When releasing the deep posterior compartment, which nerve is most closely associated with the contents of this compartment and at risk if dissection is too deep?

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

Correct Answer & Explanation

. Tibial nerve

Explanation

The deep posterior compartment of the lower leg contains the tibialis posterior, flexor digitorum longus, and flexor hallucis longus muscles. The tibial nerve and posterior tibial artery run within this compartment, intimately associated with these muscles. When releasing the deep posterior compartment, especially from a medial incision, care must be taken to effectively decompress the fascia without injuring the neurovascular bundle.

Question 8583

Topic: 2. Trauma

A 32-year-old male sustains a proximal third radius shaft fracture and undergoes open reduction and internal fixation via an anterior (Henry) approach.

During the approach, the supinator muscle must be elevated off the radius. To safely reflect the supinator and protect the posterior interosseous nerve (PIN), how should the forearm be positioned during muscle elevation?

. Full pronation
. Neutral rotation
. Full supination
. 45 degrees of pronation
. Variable depending on the fracture plane

Correct Answer & Explanation

. Full supination

Explanation

During the anterior (Henry) approach to the proximal radius, the forearm should be placed in full supination when reflecting the supinator muscle laterally. Full supination shifts the posterior interosseous nerve (PIN) further laterally and posteriorly, pulling it away from the anterior surgical field and minimizing the risk of traction or transection.

Question 8584

Topic: 2. Trauma

A 22-year-old male develops acute compartment syndrome of the lower leg following a high-energy tibial plateau fracture. The surgeon opts for a standard two-incision, four-compartment fasciotomy. Through the lateral incision, both the anterior and lateral compartments are released. Which key anatomic structure serves as the boundary dividing these two compartments and must be identified to ensure precise and complete release of both?

. Deep posterior fascia
. Anterior intermuscular septum
. Transverse intermuscular septum
. Interosseous membrane
. Superficial peroneal nerve

Correct Answer & Explanation

. Anterior intermuscular septum

Explanation

The anterior intermuscular septum anatomically separates the anterior compartment from the lateral compartment in the leg. During a lateral fasciotomy incision, the surgeon must identify this septum to confidently incise the fascia anterior to it (releasing the anterior compartment) and posterior to it (releasing the lateral compartment). The superficial peroneal nerve courses within the lateral compartment and must be protected, but the septum itself is the defining boundary.

Question 8585

Topic: 2. Trauma

A 28-year-old man develops acute compartment syndrome of the forearm following a crush injury. A volar Henry approach is utilized for fasciotomy. In the proximal third of the forearm, the radial artery must be identified and protected. Between which two muscles does the radial artery run in this specific proximal segment?

. Flexor carpi radialis and Palmaris longus
. Flexor digitorum superficialis and Flexor carpi ulnaris
. Pronator teres and Flexor carpi radialis
. Brachioradialis and Flexor carpi radialis
. Brachioradialis and Pronator teres

Correct Answer & Explanation

. Brachioradialis and Flexor carpi radialis

Explanation

In the proximal third of the forearm, the radial artery courses between the brachioradialis (laterally) and the pronator teres (medially). In the middle third, it lies between the brachioradialis and the flexor carpi radialis (FCR). In the distal third, it becomes more superficial between the tendons of the brachioradialis and FCR.

Question 8586

Topic: 2. Trauma

A 45-year-old female is undergoing an anterolateral approach to the distal tibia for a pilon fracture plating. To avoid iatrogenic injury to the superficial peroneal nerve, the surgeon must be aware of its typical anatomical course. At what approximate distance from the tip of the lateral malleolus does the superficial peroneal nerve typically pierce the crural fascia to become subcutaneous?

. 2 to 4 cm
. 5 to 8 cm
. 10 to 12 cm
. 15 to 18 cm
. 20 to 22 cm

Correct Answer & Explanation

. 10 to 12 cm

Explanation

The superficial peroneal nerve typically pierces the deep crural fascia to become subcutaneous in the distal third of the leg, approximately 10 to 12 cm (about 4.5 inches) proximal to the tip of the lateral malleolus. After piercing the fascia, it divides into the medial and intermediate dorsal cutaneous nerves to supply sensation to the dorsum of the foot. Awareness of this transition is crucial to prevent nerve injury during anterolateral approaches.

Question 8587

Topic: Upper Extremity Trauma

A 31-year-old male presents with a suspected Essex-Lopresti injury after a fall on an outstretched hand. He has pain at the elbow and wrist. Which portion of the interosseous membrane of the forearm is the primary stabilizer against longitudinal radioulnar translation?

. Distal oblique bundle
. Central band
. Proximal oblique cord
. Dorsal oblique accessory cord
. Triangular fibrocartilage complex

Correct Answer & Explanation

. Central band

Explanation

The central band of the interosseous membrane (IOM) is the thickest and most critical portion for providing longitudinal stability to the forearm, transferring force from the radius to the ulna. In an Essex-Lopresti injury, which consists of a radial head fracture, disruption of the DRUJ, and a longitudinal tear of the IOM, the central band is disrupted, leading to proximal migration of the radius if the radial head is not reconstructed or replaced.

Question 8588

Topic: 2. Trauma

A 24-year-old man presents with a closed distal third diaphyseal humerus fracture (Holstein-Lewis fracture) and an associated wrist drop on presentation. During surgical exploration via a posterior approach, the radial nerve is identified. In the posterior compartment of the arm, the radial nerve travels in the spiral groove between which two muscles?

. Brachialis and brachioradialis
. Lateral head of the triceps and medial head of the triceps
. Long head of the triceps and lateral head of the triceps
. Coracobrachialis and medial head of the triceps
. Biceps brachii and brachialis

Correct Answer & Explanation

. Lateral head of the triceps and medial head of the triceps

Explanation

In the posterior aspect of the arm, the radial nerve travels in the spiral (radial) groove of the humerus. It lies directly on the periosteum and passes between the medial and lateral heads of the triceps before piercing the lateral intermuscular septum to enter the anterior compartment. The lateral head forms the roof of the groove.

Question 8589

Topic: 2. Trauma

A surgeon is applying a fine wire circular external fixator for a complex tibial plateau fracture. When placing transfixion wires in the proximal third of the tibia, which anatomic structures dictate the safe zone boundary posteromedially to avoid iatrogenic neurovascular injury?

. Saphenous nerve and great saphenous vein
. Common peroneal nerve
. Anterior tibial artery
. Deep peroneal nerve
. Sural nerve and small saphenous vein

Correct Answer & Explanation

. Saphenous nerve and great saphenous vein

Explanation

When placing pins and wires in the proximal tibia, the posteromedial safe zone is bounded posteriorly by the pes anserinus tendons, the saphenous nerve, and the great saphenous vein. Wires inserted from anterolateral to posteromedial must exit anterior to these structures to avoid injury. The common peroneal nerve is at risk laterally near the fibular neck.

Question 8590

Topic: 2. Trauma

A 68-year-old woman sustains a displaced femoral neck fracture. Which of the following vessels is the primary contributor to the blood supply of the femoral head in an adult and is most at risk of disruption in this injury?

. Artery of the ligamentum teres
. Ascending branch of the lateral femoral circumflex artery
. Lateral epiphyseal branches of the medial femoral circumflex artery
. Inferior gluteal artery
. Deep branch of the superior gluteal artery

Correct Answer & Explanation

. Lateral epiphyseal branches of the medial femoral circumflex artery

Explanation

The primary blood supply to the adult femoral head comes from the lateral epiphyseal (retinacular) branches of the medial femoral circumflex artery (MFCA). The MFCA courses posterior to the femoral neck and provides the dominant blood supply. The artery of the ligamentum teres (a branch of the obturator artery) supplies only a small, variable portion of the femoral head in adults.

Question 8591

Topic: Upper Extremity Trauma

A 28-year-old cyclist sustains a severe type V acromioclavicular (AC) joint separation after being thrown over the handlebars. He fails conservative management and undergoes an anatomic coracoclavicular (CC) ligament reconstruction. To accurately recreate the biomechanics of the native ligaments, the surgeon must drill the clavicular tunnels mimicking the anatomic footprints. Which of the following accurately describes the anatomic orientation of the conoid and trapezoid ligaments?

. The conoid is medial and posterior; the trapezoid is lateral and anterior
. The conoid is medial and anterior; the trapezoid is lateral and posterior
. The conoid is lateral and posterior; the trapezoid is medial and anterior
. The conoid is lateral and anterior; the trapezoid is medial and posterior
. Both ligaments insert symmetrically along the midline of the clavicle

Correct Answer & Explanation

. The conoid is medial and posterior; the trapezoid is lateral and anterior

Explanation

The coracoclavicular (CC) ligament complex consists of the conoid and trapezoid ligaments, which are the primary vertical restraints of the AC joint. The conoid ligament is cone-shaped and attaches to the conoid tubercle on the posteromedial aspect of the inferior clavicle. The trapezoid ligament is broad and attaches anterolaterally to the trapezoid ridge. Therefore, relative to each other, the conoid is medial and posterior, while the trapezoid is lateral and anterior. Recreating this footprint is essential during anatomic CC reconstructions.

Question 8592

Topic: 2. Trauma

A 22-year-old soccer player sustains a twisting knee injury. Radiographs demonstrate a small avulsion fracture of the lateral tibial plateau just distal to the articular surface (Segond fracture). Biomechanical studies demonstrate that the structure avulsed in this injury pattern primarily resists which of the following forces?

. Valgus opening
. Internal tibial rotation
. External tibial rotation
. Posterior tibial translation
. Varus opening in extension

Correct Answer & Explanation

. Internal tibial rotation

Explanation

The Segond fracture is a pathognomonic avulsion fracture of the anterolateral complex (specifically the anterolateral ligament [ALL] or anterolateral capsule). This injury is highly associated with an anterior cruciate ligament (ACL) tear. Biomechanically, the ALL acts as an important secondary stabilizer to internal tibial rotation, especially at higher flexion angles.

Question 8593

Topic: Upper Extremity Trauma

A 30-year-old competitive weightlifter feels a sudden 'pop' in his anterior chest while performing a heavy bench press, followed by immediate weakness and ecchymosis over the anterior axillary fold. He is diagnosed with a complete rupture of the pectoralis major tendon. During surgical repair, a thorough understanding of the insertional anatomy is essential. How does the sternocostal head insert relative to the clavicular head on the lateral lip of the bicipital groove?

. Distal and anterior
. Distal and posterior
. Proximal and anterior
. Proximal and posterior
. Co-joined and indistinguishable

Correct Answer & Explanation

. Distal and posterior

Explanation

The pectoralis major has a complex twisted insertion on the proximal humerus. The clavicular head inserts anteriorly and distally, while the sternocostal head twists 180 degrees upon itself such that its inferior-most fibers insert most proximally and posteriorly (deep) to the clavicular head. The sternocostal head is placed under maximum tension during the eccentric phase of a bench press and is the most commonly ruptured segment.

Question 8594

Topic: Upper Extremity Trauma
A 25-year-old cyclist falls directly onto his shoulder. Radiographs demonstrate 150% superior displacement of the distal clavicle relative to the acromion. Physical examination notes a severe clinical deformity and the MRI shows disruption of the deltotrapezial fascia along with torn acromioclavicular and coracoclavicular ligaments. According to the Rockwood classification, what type of injury is this and what is the generally recommended treatment?
. Type III; conservative management with a sling
. Type III; surgical reconstruction
. Type V; conservative management with a sling
. Type V; surgical reconstruction
. Type IV; surgical reconstruction

Correct Answer & Explanation

. Type V; surgical reconstruction

Explanation

This is a Rockwood Type V acromioclavicular (AC) joint injury. It is characterized by 100-300% superior displacement of the clavicle, complete rupture of the AC and CC ligaments, and gross disruption of the deltotrapezial fascia resulting in severe soft tissue stripping. Type V injuries are generally treated with surgical reconstruction to restore shoulder biomechanics. Type III injuries have up to 100% displacement and are often managed conservatively, whereas Type IV injuries involve posterior displacement of the clavicle into or through the trapezius.

Question 8595

Topic: Upper Extremity Trauma
A 31-year-old male cyclist falls directly onto his right shoulder. Clinical examination reveals a prominent distal clavicle. Radiographs demonstrate 150% superior displacement of the distal clavicle relative to the acromion, with a significantly increased coracoclavicular distance. Which of the following structures must be completely disrupted to result in this radiographic appearance?
. Acromioclavicular ligaments only
. Acromioclavicular and coracoclavicular ligaments with an intact deltotrapezial fascia
. Acromioclavicular and coracoclavicular ligaments with disruption of the deltotrapezial fascia
. Coracoacromial ligament and coracoclavicular ligaments
. Sternoclavicular ligaments and costoclavicular ligaments

Correct Answer & Explanation

. Acromioclavicular and coracoclavicular ligaments with disruption of the deltotrapezial fascia

Explanation

Superior displacement of the distal clavicle between 100% and 300% relative to the acromion represents a Rockwood Type V acromioclavicular (AC) joint separation. This severe degree of displacement is only biomechanically possible when there is a complete disruption of the acromioclavicular ligaments, the coracoclavicular ligaments (conoid and trapezoid), and the deltotrapezial fascia. A Type III injury (up to 100% displacement) retains an intact deltotrapezial fascia.

Question 8596

Topic: Upper Extremity Trauma

A 22-year-old collegiate baseball pitcher presents with posterior elbow pain during the deceleration phase of throwing and a progressive loss of terminal extension. Exam shows posteromedial tenderness and pain with forced elbow extension while valgus stress is applied.

Radiographs demonstrate posteromedial olecranon osteophytes. If operative management is chosen, what is a critical technical consideration?

. Performing a generous 10 mm wedge resection of the olecranon to ensure full extension
. Limiting olecranon resection to less than 3 mm to avoid increasing strain on the UCL
. Performing a prophylactic lateral ulnar collateral ligament (LUCL) reconstruction
. Resecting the coronoid tip to decompress the anterior capsule
. Transposing the ulnar nerve subcutaneously in all cases

Correct Answer & Explanation

. Limiting olecranon resection to less than 3 mm to avoid increasing strain on the UCL

Explanation

Valgus extension overload (VEO) results in posteromedial olecranon impingement and osteophyte formation, often coexisting with chronic ulnar collateral ligament (UCL) insufficiency. Resecting more than 3 mm of the posteromedial olecranon removes a secondary bony constraint to valgus stress, which significantly increases strain on the UCL and can unmask or worsen frank valgus instability.

Question 8597

Topic: Upper Extremity Trauma

A 26-year-old mountain biker sustains a fall onto his shoulder. Clinical examination reveals a prominent distal clavicle.

Radiographs confirm a Type V acromioclavicular (AC) joint separation. The surgeon plans an anatomic coracoclavicular (CC) ligament reconstruction. To accurately recreate the native anatomy, where should the clavicular tunnel for the conoid ligament be placed?

. 4.5 cm medial to the distal clavicle and centered anterior-to-posterior
. 4.5 cm medial to the distal clavicle and slightly posterior to the midline
. 3.0 cm medial to the distal clavicle and slightly anterior to the midline
. 1.5 cm medial to the distal clavicle and centered anterior-to-posterior
. 1.5 cm medial to the distal clavicle and slightly posterior to the midline

Correct Answer & Explanation

. 4.5 cm medial to the distal clavicle and slightly posterior to the midline

Explanation

Anatomic reconstruction of the CC ligaments requires precise tunnel placement. The native conoid ligament inserts approximately 4.5 cm medial to the distal end of the clavicle and slightly posterior to its midline. The trapezoid ligament inserts approximately 3.0 cm medial to the distal end and slightly anterior. Correct placement optimizes the biomechanical stability of the construct.

Question 8598

Topic: Upper Extremity Trauma
A 28-year-old male cyclist falls directly onto his right shoulder. Radiographs show a 150% superior displacement of the distal clavicle relative to the acromion. Physical exam reveals severe soft tissue tenting and pain. According to the Rockwood classification, what is the injury type and most appropriate management?
. Rockwood Type III, nonoperative management
. Rockwood Type II, sling and early physical therapy
. Rockwood Type V, surgical reconstruction of the coracoclavicular ligaments
. Rockwood Type IV, closed reduction and spica casting
. Rockwood Type VI, surgical reconstruction of the acromioclavicular capsule only

Correct Answer & Explanation

. Rockwood Type V, surgical reconstruction of the coracoclavicular ligaments

Explanation

This is a Rockwood Type V acromioclavicular (AC) joint separation, characterized by >100% (typically 100-300%) superior displacement of the distal clavicle into the trapezius fascia, presenting with gross deformity and soft tissue tenting. Surgical reconstruction of the coracoclavicular (CC) ligaments is the indicated treatment for Type V injuries, whereas Type III injuries (up to 100% displacement) often undergo an initial trial of nonoperative management.

Question 8599

Topic: Upper Extremity Trauma

A 30-year-old competitive weightlifter feels a sudden 'pop' and tearing sensation in his anterior axilla while performing a heavy bench press. Examination reveals extensive ecchymosis over the medial arm and a loss of the normal anterior axillary fold contour. Weakness is most pronounced with internal rotation and adduction of the arm. Which of the following describes the most common anatomical location of this specific injury?

. Avulsion of the clavicular head from its humeral insertion
. Avulsion of the sternal head from its humeral insertion
. Tear of the sternal head at the musculotendinous junction
. Tear of the clavicular head at the musculotendinous junction
. Mid-substance rupture of the combined muscle belly

Correct Answer & Explanation

. Avulsion of the sternal head from its humeral insertion

Explanation

The patient has sustained a pectoralis major rupture, classically occurring during the eccentric phase of a bench press. The most common site of injury is an avulsion of the sternal head from its insertion on the proximal humerus, lateral to the bicipital groove. Because the sternal head inserts deep and proximal to the clavicular head, extreme tension is placed selectively on the inferior (sternal) fibers when the arm is extended and externally rotated, making it highly susceptible to isolated tearing or avulsion.

Question 8600

Topic: 2. Trauma

A 21-year-old collegiate distance runner complains of bilateral, dull, aching anterolateral leg pain that reliably begins 15 minutes into a run and resolves after 30 minutes of rest. Intracompartmental pressure testing is performed to evaluate for chronic exertional compartment syndrome (CECS). According to the Pedowitz criteria, which of the following compartment pressure measurements confirms the diagnosis?

. Resting pressure > 10 mm Hg
. 1-minute post-exercise pressure > 30 mm Hg
. 5-minute post-exercise pressure > 15 mm Hg
. 15-minute post-exercise pressure > 10 mm Hg
. 1-minute post-exercise pressure > 20 mm Hg

Correct Answer & Explanation

. 1-minute post-exercise pressure > 30 mm Hg

Explanation

The diagnosis of chronic exertional compartment syndrome (CECS) is typically confirmed using the Pedowitz criteria for intracompartmental pressure measurements. The criteria are: 1) a pre-exercise (resting) pressure >= 15 mm Hg, 2) a 1-minute post-exercise pressure >= 30 mm Hg, or 3) a 5-minute post-exercise pressure >= 20 mm Hg. Meeting any one of these criteria is considered diagnostic for CECS.

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