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Upper Extremity Trauma MCQs

Practice Set 23 of 24

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

Question 441

Topic: Upper Extremity Trauma

Current anatomical studies evaluating the vascular supply to the proximal humerus demonstrate that the principal blood supply to the humeral head is derived primarily from which of the following vessels?

. Anterior humeral circumflex artery
. Posterior humeral circumflex artery
. Thoracoacromial artery
. Subscapular artery
. Profunda brachii artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

Historically, the anterior humeral circumflex artery (via its anterolateral ascending branch, the arcuate artery) was thought to be the main blood supply. However, more recent quantitative anatomical studies (e.g., Brooks et al., and Hettrich et al.) have demonstrated that the posterior humeral circumflex artery actually provides the majority (up to 64%) of the blood supply to the humeral head.

Question 442

Topic: Upper Extremity Trauma

During a coracoclavicular (CC) ligament reconstruction for a chronic Type V acromioclavicular joint separation, the surgeon must replicate the native anatomy of the conoid and trapezoid ligaments. Which of the following best describes the anatomical orientation of the conoid ligament insertion on the clavicle relative to the trapezoid ligament?

. Posterior and medial
. Posterior and lateral
. Anterior and medial
. Anterior and lateral
. Directly inferior

Correct Answer & Explanation

. Posterior and medial

Explanation

The coracoclavicular (CC) ligaments consist of the conoid and trapezoid. The conoid ligament is positioned medial and posterior to the trapezoid ligament. It inserts on the conoid tubercle of the posterior-inferior clavicle, while the trapezoid inserts anterolaterally on the trapezoid line.

Question 443

Topic: Upper Extremity Trauma

A 45-year-old bodybuilder feels a 'pop' in his posterior distal arm while performing heavy bench presses. MRI confirms a complete triceps tendon rupture. During surgical repair, an anatomical understanding of the triceps footprint is essential. The normal triceps insertion is best described as:

. A narrow transverse strip located strictly at the proximal tip of the olecranon
. A broad, dome-shaped area covering the posterior-proximal olecranon, extending distally
. A split insertion onto the coronoid process and proximal ulna
. An attachment onto the lateral epicondyle merging with the anconeus fascia
. A focal insertion solely within the olecranon fossa of the humerus

Correct Answer & Explanation

. A broad, dome-shaped area covering the posterior-proximal olecranon, extending distally

Explanation

The triceps tendon does not insert merely on the tip of the olecranon. Its anatomic footprint is broad, dome-shaped, and covers a wide area on the posterior-proximal olecranon. Restoring this broad footprint during repair (often using transosseous-equivalent double-row or strong single-row techniques) is important to recreate normal biomechanical pull and strength.

Question 444

Topic: Upper Extremity Trauma

A 22-year-old collegiate baseball pitcher complains of posterior elbow pain that is worse during the deceleration phase of throwing. Examination reveals a 15-degree flexion contracture and point tenderness over the posteromedial olecranon. If a conservative program fails, what is the best initial surgical intervention?

. Medial ulnar collateral ligament reconstruction
. Open reduction and internal fixation of the olecranon
. Arthroscopic excision of the posteromedial olecranon osteophyte
. Ulnar nerve anterior transposition
. Arthroscopic capsular release of the anterior capsule

Correct Answer & Explanation

. Arthroscopic excision of the posteromedial olecranon osteophyte

Explanation

This patient has valgus extension overload (Pitcher's elbow), which results from repetitive valgus stress and extreme extension during the deceleration phase of throwing. This leads to posteromedial impingement and the formation of a posteromedial olecranon osteophyte. The appropriate surgical treatment is excision of the osteophyte. Care must be taken not to resect too much olecranon (typically limiting resection to <3 mm), as over-resection dramatically increases the strain on the anterior bundle of the MUCL, potentially causing iatrogenic valgus instability.

Question 445

Topic: Upper Extremity Trauma

A 25-year-old cyclist falls directly onto his shoulder. Radiographs demonstrate the distal clavicle is displaced superiorly by 200% compared to the uninjured side. Which structures are disrupted in this specific grade of acromioclavicular (AC) joint injury?

. AC ligaments are ruptured; CC ligaments are intact
. AC ligaments and CC ligaments are ruptured; deltotrapezial fascia is intact
. AC ligaments, CC ligaments, and the deltotrapezial fascia are completely ruptured
. AC ligaments are intact; CC ligaments are ruptured
. Only the conoid ligament is ruptured

Correct Answer & Explanation

. AC ligaments, CC ligaments, and the deltotrapezial fascia are completely ruptured

Explanation

This describes a Rockwood Type V AC joint separation, characterized by >100% (up to 300%) superior displacement of the distal clavicle. Pathologically, it involves rupture of the AC ligaments, the coracoclavicular (CC) ligaments, and extensive detachment/tearing of the deltotrapezial fascia, allowing the clavicle to severely elevate subcutaneously.

Question 446

Topic: Upper Extremity Trauma

A 40-year-old male develops severe elbow stiffness secondary to heterotopic ossification (HO) following a terrible triad injury. When planning surgical excision of the HO to restore motion, what is the most reliable clinical and radiographic indicator that the ectopic bone is mature enough for safe resection?

. Exactly 6 months of elapsed time from the injury
. Normalization of serum alkaline phosphatase levels
. Cold uptake on a technetium-99m bone scan
. Sharp, distinct trabecular margins seen on plain radiographs with cessation of ROM changes
. Resolution of all soft tissue swelling

Correct Answer & Explanation

. Sharp, distinct trabecular margins seen on plain radiographs with cessation of ROM changes

Explanation

Historically, alkaline phosphatase and bone scans were used to determine HO maturity, but these have been shown to be unreliable. The current gold standard for timing surgical excision is clinical (cessation of progressive stiffness) and radiographic (appearance of sharp, distinct trabecular margins indicating mature bone on plain radiographs).

Question 447

Topic: Upper Extremity Trauma

A 32-year-old bodybuilder ruptures his pectoralis major tendon at its insertion during a heavy bench press. Which of the following accurately describes the anatomical orientation of the normal pectoralis major tendon at its insertion on the proximal humerus?

. The clavicular head inserts deep and proximal to the sternal head
. The sternal head twists 180 degrees so its lowest fibers insert highest (proximal) and deep to the clavicular head
. Both heads blend completely, making it impossible to distinguish layers at the footprint
. The clavicular head inserts deep and distal to the sternal head
. The sternal head inserts superficial and distal to the clavicular head

Correct Answer & Explanation

. The sternal head twists 180 degrees so its lowest fibers insert highest (proximal) and deep to the clavicular head

Explanation

The pectoralis major tendon consists of two main heads: clavicular and sternocostal. As the tendon courses laterally to insert on the lateral lip of the bicipital groove, it twists 180 degrees. The clavicular head inserts proximally and superficially, while the sternocostal head twists such that its most inferior fibers insert the most superiorly (proximally) and deep to the clavicular head.

Question 448

Topic: Upper Extremity Trauma
A 28-year-old cyclist falls directly onto his shoulder. Radiographs demonstrate a displaced acromioclavicular (AC) joint injury. The clavicle is displaced superiorly by 150% of the normal joint space relative to the acromion. The deltotrapezial fascia is clinically disrupted. Which Rockwood classification type best describes this injury?
. Type II
. Type III
. Type IV
. Type V
. Type VI

Correct Answer & Explanation

. Type V

Explanation

Rockwood Type V AC joint separations are characterized by complete tearing of the AC and CC ligaments, severe disruption of the deltotrapezial fascia, and severe superior displacement of the distal clavicle by >100% (often up to 300%) compared to the normal contralateral side.

Question 449

Topic: Upper Extremity Trauma

A surgeon performs an anatomic coracoclavicular (CC) ligament reconstruction for a chronic Type V acromioclavicular joint separation. To accurately reproduce the native biomechanics, drill holes are placed in the clavicle corresponding to the native footprints of the conoid and trapezoid ligaments. What are the approximate distances of these insertions from the distal aspect of the clavicle?

. Conoid at 15 mm, Trapezoid at 30 mm
. Conoid at 25 mm, Trapezoid at 15 mm
. Conoid at 45 mm, Trapezoid at 25 mm
. Conoid at 25 mm, Trapezoid at 45 mm
. Both tunnels placed symmetrically at exactly 30 mm

Correct Answer & Explanation

. Conoid at 45 mm, Trapezoid at 25 mm

Explanation

The native footprints of the CC ligaments are critical for anatomic reconstruction. The conoid ligament is positioned more medial and slightly posterior, inserting approximately 45 mm from the distal clavicle. The trapezoid ligament is more lateral and anterior, inserting approximately 25 to 30 mm from the distal clavicle.

Question 450

Topic: Upper Extremity Trauma
A 28-year-old male presents after falling directly onto his left shoulder during a rugby match. On examination, there is obvious superior displacement of the distal clavicle relative to the acromion, and a significant 'step-off' deformity. The patient experiences severe pain with any arm movement, and the piano key sign is positive. Radiographs show complete disruption of the AC ligaments and coracoclavicular ligaments, with significant superior displacement of the clavicle but no posterior displacement or involvement of the deltoid/trapezius fascia. According to the Rockwood classification, what type of AC joint injury is most likely present?
. Type II
. Type III
. Type IV
. Type V
. Type VI

Correct Answer & Explanation

. Type III

Explanation

The clinical presentation describes a complete disruption of both the acromioclavicular (AC) and coracoclavicular (CC) ligaments, with significant superior displacement of the clavicle, consistent with a Rockwood Type III injury. Type II involves AC ligament disruption and sprain/partial CC ligament injury, with only partial superior displacement. Type IV involves posterior displacement of the clavicle into the trapezius. Type V involves severe superior displacement (>25-100% of acromial height) with extensive deltoid and trapezius fascial stripping. Type VI involves inferior displacement of the clavicle.

Question 451

Topic: Upper Extremity Trauma

Which anatomical structure is primarily responsible for preventing superior migration of the distal clavicle?

. Acromioclavicular capsule
. Coracoclavicular ligaments (conoid and trapezoid)
. Deltoid muscle
. Trapezius muscle
. Pectoralis minor muscle

Correct Answer & Explanation

. Coracoclavicular ligaments (conoid and trapezoid)

Explanation

The coracoclavicular (CC) ligaments, composed of the conoid and trapezoid ligaments, are the primary vertical stabilizers of the AC joint. While the AC capsule and surrounding musculature (deltoid, trapezius) contribute to overall stability, the CC ligaments are critical in preventing significant superior displacement of the clavicle relative to the acromion.

Question 452

Topic: Upper Extremity Trauma
What is the primary differentiating feature between a Rockwood Type II and a Type III AC joint injury?
. Complete vs. partial tear of the deltoid and trapezius fascia.
. Partial vs. complete tear of the acromioclavicular ligaments.
. Presence vs. absence of a 'step-off' deformity.
. Partial vs. complete tear of the coracoclavicular ligaments.
. Anterior vs. posterior displacement of the clavicle.

Correct Answer & Explanation

. Partial vs. complete tear of the coracoclavicular ligaments.

Explanation

The key differentiation between Rockwood Type II and Type III lies in the integrity of the coracoclavicular ligaments. In Type II, the AC ligaments are torn, and the CC ligaments are sprained or partially torn, leading to subluxation but not complete dislocation of the clavicle from the acromion (CC distance is normal or minimally increased <25%). In Type III, both AC and CC ligaments are completely torn, resulting in frank dislocation and a significant increase in the CC distance (>25% compared to contralateral) and a distinct 'step-off' deformity. AC ligaments are torn in both to varying degrees, but CC ligament integrity is the critical differentiator for superior migration.

Question 453

Topic: Upper Extremity Trauma
A patient with a suspected AC joint injury has no visible deformity, minimal pain with direct palpation over the AC joint, and pain primarily with cross-body adduction. Radiographs are normal. What Rockwood type is this most consistent with?
. Type 0
. Type I
. Type II
. Type III
. Type IV

Correct Answer & Explanation

. Type I

Explanation

This presentation describes a Rockwood Type I injury. It involves a sprain of the AC ligaments without significant tearing, minimal to no displacement, and normal radiographs (AC and CC distances are normal). Pain is localized to the AC joint, often exacerbated by specific movements like cross-body adduction. Type 0 is not a standard Rockwood classification category. Type II would show subluxation and some CC ligament injury, with mild radiographic changes.

Question 454

Topic: Upper Extremity Trauma

Which of the following ligaments provides the primary horizontal stability to the AC joint?

. Conoid ligament
. Trapezoid ligament
. Acromioclavicular ligaments (superior and inferior)
. Coracoacromial ligament
. Capsular ligaments of the glenohumeral joint

Correct Answer & Explanation

. Acromioclavicular ligaments (superior and inferior)

Explanation

The acromioclavicular (AC) ligaments, particularly the superior and inferior AC ligaments, are the primary stabilizers against horizontal translation (anterior-posterior shear) of the AC joint. The coracoclavicular ligaments (conoid and trapezoid) provide vertical stability. The coracoacromial ligament forms part of the coracoacromial arch and is not a direct stabilizer of the AC joint itself.

Question 455

Topic: Upper Extremity Trauma

The coracoclavicular distance is measured on an AP radiograph. What structures does this measurement assess the integrity of?

. Acromioclavicular ligaments
. Coracoacromial ligament
. Coracoclavicular ligaments
. Glenohumeral ligaments
. Sternoclavicular joint capsule

Correct Answer & Explanation

. Coracoclavicular ligaments

Explanation

The coracoclavicular (CC) distance, measured from the superior aspect of the coracoid process to the inferior cortex of the clavicle, directly reflects the integrity of the coracoclavicular ligaments (conoid and trapezoid). An increase in this distance compared to the contralateral side indicates tearing of these ligaments and superior displacement of the clavicle. While AC ligaments are also involved in injury, the CC distance specifically evaluates the CC ligaments.

Question 456

Topic: Upper Extremity Trauma
Which of the following describes the anatomical structures involved in a Rockwood Type II AC joint injury?
. AC ligaments sprained, CC ligaments intact.
. AC ligaments torn, CC ligaments sprained or partially torn, mild superior subluxation.
. AC ligaments and CC ligaments completely torn, significant superior dislocation.
. AC ligaments and CC ligaments completely torn, posterior displacement of clavicle.
. AC ligaments and CC ligaments completely torn, inferior displacement of clavicle.

Correct Answer & Explanation

. AC ligaments torn, CC ligaments sprained or partially torn, mild superior subluxation.

Explanation

A Rockwood Type II injury involves a torn acromioclavicular (AC) capsule and ligaments, with a sprain or partial tear of the coracoclavicular (CC) ligaments. This results in subluxation of the AC joint, meaning there is some superior displacement, but not a complete dislocation, and the CC distance is only minimally increased (less than 25% compared to the contralateral side). Type I has only sprained AC ligaments and intact CC ligaments. Type III has complete tears of both AC and CC ligaments.

Question 457

Topic: Upper Extremity Trauma

The Rockwood classification system primarily describes AC joint injuries based on the degree of displacement and the integrity of which two ligamentous structures?

. Glenohumeral ligaments and joint capsule
. Coracoacromial ligament and deltoid fascia
. Acromioclavicular (AC) ligaments and coracoclavicular (CC) ligaments
. Transverse humeral ligament and rotator cuff tendons
. Superior glenohumeral ligament and inferior glenohumeral ligament

Correct Answer & Explanation

. Acromioclavicular (AC) ligaments and coracoclavicular (CC) ligaments

Explanation

The Rockwood classification system for AC joint injuries is fundamentally based on the progressive disruption of the acromioclavicular (AC) ligaments and the coracoclavicular (CC) ligaments (conoid and trapezoid), and the resulting displacement of the clavicle. The integrity of these two ligament groups dictates the stability and classification type.

Question 458

Topic: Upper Extremity Trauma
A patient presents with pain over the AC joint. On examination, there is no obvious deformity or step-off. Palpation over the AC joint elicits tenderness. Cross-body adduction test is positive. Radiographs, including stress views, show no abnormal widening of the AC joint or increased coracoclavicular distance. This clinical picture is most consistent with which Rockwood classification type?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type I

Explanation

This presentation is consistent with a Rockwood Type I AC joint injury. It involves a sprain of the AC ligaments with no significant tearing, thus no radiographic changes (normal AC and CC distances, even on stress views), and no visible deformity. Tenderness over the AC joint and a positive cross-body adduction test are typical. Type II would show some subluxation and minimal radiographic changes, and Type III would show frank dislocation and clear radiographic abnormalities.

Question 459

Topic: Upper Extremity Trauma
A patient presents with a palpable gap between the distal clavicle and the acromion, and significant pain on palpation. Radiographs show a widened AC joint space but the coracoclavicular distance is within normal limits. This suggests disruption of the AC ligaments, but intact CC ligaments. What Rockwood type is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

This describes a Rockwood Type II injury. There is a complete tear of the acromioclavicular ligaments, causing widening of the AC joint space and superior subluxation. However, the coracoclavicular ligaments are intact or only partially sprained, meaning the coracoclavicular distance remains normal or only minimally increased (<25% of contralateral), preventing frank dislocation. Type I would have normal radiographs. Type III would have increased CC distance.

Question 460

Topic: Upper Extremity Trauma

Which ligament, if torn, allows for the 'piano key' sign and significant superior displacement of the clavicle?

. Coracoacromial ligament
. Transverse humeral ligament
. Coracoclavicular ligaments
. Superior glenohumeral ligament
. Acromioclavicular ligaments

Correct Answer & Explanation

. Coracoclavicular ligaments

Explanation

The 'piano key' sign and significant superior displacement are hallmark signs of complete disruption of the coracoclavicular ligaments (conoid and trapezoid). These ligaments are the primary restraints to superior migration of the clavicle. While AC ligaments are also torn in these injuries, it is the CC ligament disruption that permits the dramatic vertical instability.

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