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Upper Extremity Trauma MCQs

Practice Set 19 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 361

Topic: Upper Extremity Trauma

What is the most appropriate method to confirm proper screw length and avoid neurovascular injury or joint penetration when placing screws in a distal humerus locking plate?

. Using a depth gauge after drilling, without fluoroscopic assistance.
. Relying solely on tactile feel during screw insertion.
. Employing a combination of depth gauge measurements and intraoperative fluoroscopy in multiple planes.
. Placing screws bicortically regardless of surrounding anatomy.
. Using only monocortical screws to minimize risk.

Correct Answer & Explanation

. Employing a combination of depth gauge measurements and intraoperative fluoroscopy in multiple planes.

Explanation

In complex anatomical regions like the distal humerus, where neurovascular structures are abundant and articular penetration is a significant risk, a combination of precise depth gauge measurements and intraoperative fluoroscopy in multiple planes (AP, lateral, obliques) is essential to confirm appropriate screw length, bicortical purchase (if desired), and to ensure no penetration of the joint surface or compromise of neurovascular structures. Relying solely on depth gauge or tactile feel is insufficient. While monocortical screws may be used in specific scenarios, they are not the general rule, and bicortical screws are often desired for strength, requiring careful measurement.

Question 362

Topic: Upper Extremity Trauma

What is the typical position of the elbow for applying a posterior approach with an olecranon osteotomy during distal humerus fracture repair?

. Full extension
. Full flexion
. Semi-flexion (approximately 30 degrees)
. Flexion to 90 degrees
. Variable, depending on surgeon preference

Correct Answer & Explanation

. Flexion to 90 degrees

Explanation

For a posterior approach with an olecranon osteotomy, the elbow is typically positioned in approximately 90 degrees of flexion. This allows for optimal exposure of the posterior distal humerus, provides access to the ulnar nerve, and facilitates the performance and subsequent fixation of the olecranon osteotomy. It also puts the triceps under slight tension which can aid in dissection. Full extension or full flexion might hinder certain steps of the exposure or reduction.

Question 363

Topic: Upper Extremity Trauma

What is the typical anatomical location of the primary blood supply to the distal humerus?

. Branches from the anterior humeral circumflex artery
. The nutrient artery originating from the brachial artery, entering proximally
. Direct branches from the ulnar collateral arteries
. The posterior interosseous artery
. The recurrent radial artery

Correct Answer & Explanation

. The nutrient artery originating from the brachial artery, entering proximally

Explanation

The primary blood supply to the distal humerus, as with the rest of the humerus, typically comes from the nutrient artery, a branch of the brachial artery, which enters the shaft proximally and sends branches distally. Additional supply comes from periosteal vessels and contributions from collateral arteries (superior ulnar collateral, inferior ulnar collateral, radial collateral) that form an anastomotic network around the elbow. The anterior humeral circumflex artery supplies the proximal humerus. The posterior interosseous and recurrent radial arteries are primarily forearm vessels.

Question 364

Topic: Upper Extremity Trauma

What is the most common approach to assess the integrity of the interosseous membrane (IOM) when an Essex-Lopresti lesion is suspected?

. Direct visualization during open surgery
. Standard wrist radiographs
. MRI of the forearm
. Ultrasound of the forearm
. CT scan of the elbow

Correct Answer & Explanation

. MRI of the forearm

Explanation

MRI of the forearm is the most effective imaging modality for directly assessing the integrity of the interosseous membrane (IOM). It can visualize tears, avulsions, or other disruptions of the IOM that are critical for diagnosing an Essex-Lopresti lesion. Standard radiographs might show proximal radial migration (indirect sign), but MRI provides direct visualization of the soft tissue injury. CT is good for bone, ultrasound is less reliable for deep IOM structures.

Question 365

Topic: Upper Extremity Trauma

The articular surface of the olecranon forms part of which joint?

. Humeroradial joint
. Proximal radioulnar joint
. Distal radioulnar joint
. Ulnohumeral joint
. Acromioclavicular joint

Correct Answer & Explanation

. Ulnohumeral joint

Explanation

The articular surface of the olecranon forms the proximal portion of the trochlear notch, which articulates with the trochlea of the humerus to form the ulnohumeral joint (D). This is the primary articulation responsible for elbow flexion and extension.

Question 366

Topic: Upper Extremity Trauma

The anconeus muscle plays a role in elbow function and stability. Where does it primarily originate and insert relative to the olecranon?

. Origin: medial epicondyle; Insertion: olecranon fossa
. Origin: lateral epicondyle; Insertion: lateral aspect of olecranon and proximal ulna
. Origin: coracoid process; Insertion: olecranon
. Origin: radial head; Insertion: coronoid process
. Origin: medial supracondylar ridge; Insertion: medial aspect of olecranon

Correct Answer & Explanation

. Origin: lateral epicondyle; Insertion: lateral aspect of olecranon and proximal ulna

Explanation

The anconeus muscle originates from the posterior surface of the lateral epicondyle of the humerus and inserts onto the lateral aspect of the olecranon and the proximal ulna (B). It assists in elbow extension and stabilizes the ulnohumeral joint, particularly during pronation and supination.

Question 367

Topic: Upper Extremity Trauma

The vascular supply to the olecranon is primarily from branches of which artery?

. Brachial artery
. Radial artery
. Ulnar artery
. Posterior interosseous artery
. Anterior interosseous artery

Correct Answer & Explanation

. Ulnar artery

Explanation

The vascular supply to the olecranon and proximal ulna is robust, primarily deriving from a periosteal network fed by recurrent branches of the ulnar artery (C), specifically the posterior ulnar recurrent artery, and to a lesser extent, the interosseous arteries. The brachial (A) artery is more proximal, and radial (B) artery branches are more lateral/distal.

Question 368

Topic: Upper Extremity Trauma

A 27-year-old male sustains an acromioclavicular (AC) joint separation following a fall onto the point of his shoulder. Radiographs demonstrate 150% superior displacement of the clavicle relative to the acromion.

Regarding the coracoclavicular (CC) ligaments ruptured in this injury, which statement accurately reflects their anatomy and biomechanical function?

. The conoid ligament is anterolateral and primarily restrains anterior-posterior translation
. The trapezoid ligament is posteromedial and primarily restrains superior-inferior translation
. The conoid ligament is posteromedial and provides the primary restraint to superior-inferior translation
. The trapezoid ligament is posteromedial and provides the primary restraint to axial compression
. Both ligaments blend together identically to provide equal restraint against posterior translation of the distal clavicle

Correct Answer & Explanation

. The conoid ligament is posteromedial and provides the primary restraint to superior-inferior translation

Explanation

The coracoclavicular (CC) ligaments consist of the conoid and trapezoid. The conoid ligament is located posteromedial and is the primary restraint to superior translation of the clavicle. The trapezoid ligament is located anterolateral and is the primary restraint to axial compression (resisting medial displacement of the scapula relative to the clavicle).

Question 369

Topic: Upper Extremity Trauma

A 26-year-old cyclist sustains a Type V acromioclavicular (AC) joint separation requiring surgical reconstruction. The surgeon plans to drill tunnels mimicking the native coracoclavicular (CC) ligaments. Which of the following accurately describes the anatomic relationship of the CC ligaments?

. The trapezoid is lateral and the conoid is medial
. The trapezoid is medial and the conoid is lateral
. Both ligaments attach strictly to the acromion
. The conoid inserts on the coracoid apex while the trapezoid inserts on the base
. The trapezoid blends seamlessly with the coracoacromial ligament

Correct Answer & Explanation

. The trapezoid is lateral and the conoid is medial

Explanation

The coracoclavicular (CC) ligaments consist of the lateral trapezoid ligament and the medial conoid ligament. The trapezoid attaches to the clavicle approximately 1.5-2.5 cm from the distal end, and the conoid attaches more medially, approximately 3.0-4.5 cm from the distal end.

Question 370

Topic: Upper Extremity Trauma

A 45-year-old male loses his footing and falls directly onto a flexed elbow. He is unable to actively extend his elbow against gravity, and a palpable gap is felt posteriorly. During operative repair of this distal triceps tendon rupture, understanding the native footprint is crucial. Which of the following describes the normal anatomic insertion of the triceps tendon on the olecranon?

. A narrow transverse band immediately adjacent to the proximal articular margin
. A V-shaped insertion blending completely with the anconeus fascia on the lateral ulna
. A broad, dome-shaped area approximately 1.1 to 1.4 cm distal to the tip of the olecranon
. A dual insertion with the medial head attaching to the sublime tubercle and the lateral head to the supinator crest
. A single discrete circular footprint exactly at the apogee of the olecranon process

Correct Answer & Explanation

. A broad, dome-shaped area approximately 1.1 to 1.4 cm distal to the tip of the olecranon

Explanation

Anatomic studies demonstrate that the triceps tendon does not insert precisely at the tip of the olecranon. The footprint is broad and dome-shaped, beginning approximately 1.1 to 1.4 cm distal to the tip of the olecranon. Repairing the tendon to the absolute tip can lead to prominent hardware and abnormal kinematics.

Question 371

Topic: Upper Extremity Trauma

During the surgical reconstruction of a chronic type V acromioclavicular (AC) joint separation, the surgeon reconstructs the coracoclavicular (CC) ligaments. The native conoid ligament inserts on the clavicle at what distance from the distal clavicle, and what is its primary biomechanical role?

. 4.5 cm / Resists anterior translation
. 4.5 cm / Resists superior translation
. 4.5 cm / Resists axial compression
. 2.5 cm / Resists posterior translation
. 2.5 cm / Resists superior translation

Correct Answer & Explanation

. 4.5 cm / Resists superior translation

Explanation

The conoid ligament inserts approximately 4.5 cm medial to the distal clavicle and primarily resists superior translation of the clavicle. The trapezoid ligament inserts more distally (approximately 2.5 cm) and primarily resists axial compression.

Question 372

Topic: Upper Extremity Trauma

A 19-year-old collegiate baseball pitcher undergoes ulnar collateral ligament (UCL) reconstruction using a palmaris longus autograft. Which bundle of the native UCL is the primary restraint to valgus stress between 30 and 120 degrees of flexion, and where does it insert?

. Anterior bundle / Sublime tubercle
. Posterior bundle / Sublime tubercle
. Transverse bundle / Olecranon
. Anterior bundle / Coronoid tip
. Posterior bundle / Radial neck

Correct Answer & Explanation

. Anterior bundle / Sublime tubercle

Explanation

The anterior bundle of the UCL is the primary restraint to valgus stress from 30 to 120 degrees of elbow flexion. It originates on the medial epicondyle and inserts on the sublime tubercle located on the anteromedial coronoid facet.

Question 373

Topic: Upper Extremity Trauma

Recent anatomical studies regarding the vascular supply of the proximal humerus demonstrate that the predominant blood supply to the humeral head is provided by which of the following vessels?

. Anterior humeral circumflex artery
. Posterior humeral circumflex artery
. Arcuate artery
. Thoracoacromial artery
. Subscapular artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

Classic teaching highlighted the anterior humeral circumflex artery as the primary supply via its arcuate branch. However, recent quantitative studies prove the posterior humeral circumflex artery provides approximately 64% of the blood supply to the humeral head.

Question 374

Topic: Upper Extremity Trauma

Recent anatomical studies have redefined the primary blood supply to the proximal humerus. Which of the following vessels is now considered to supply the majority of the humeral head?

. Anterolateral branch of the anterior humeral circumflex artery
. Arcuate artery
. Posterior humeral circumflex artery
. Thoracoacromial artery
. Subscapular artery

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

Historically, the anterior humeral circumflex artery (via the arcuate artery) was thought to provide the main blood supply. However, recent quantitative studies demonstrate that the posterior humeral circumflex artery supplies up to 64% of the humeral head.

Question 375

Topic: Upper Extremity Trauma

During a deltopectoral approach for proximal humerus plating, the cephalic vein is identified. To preserve the primary venous drainage of the deltoid muscle and minimize bleeding, the vein is typically retracted in which direction, and which artery's branch travels in this same interval?

. Medially; acromial branch of the thoracoacromial artery
. Laterally; deltoid branch of the thoracoacromial artery
. Medially; deltoid branch of the thoracoacromial artery
. Laterally; acromial branch of the thoracoacromial artery
. Laterally; anterior circumflex humeral artery

Correct Answer & Explanation

. Laterally; deltoid branch of the thoracoacromial artery

Explanation

The cephalic vein receives numerous small tributaries from the deltoid muscle. Therefore, it is typically retracted laterally with the deltoid to prevent avulsing these branches, taking care to preserve the deltoid branch of the thoracoacromial artery.

Question 376

Topic: Upper Extremity Trauma

A 45-year-old woman is evaluated for a new painful mass in her proximal humerus. She has a known history of Ollier disease. Radiographs show a destructive lesion arising from a pre-existing calcified intramedullary tumor. Which of the following genetic mutations is most strongly associated with her underlying syndrome?

. EXT1
. GNAS
. IDH1
. RB1
. USP6

Correct Answer & Explanation

. IDH1

Explanation

Ollier disease (multiple enchromatosis) and Maffucci syndrome are strongly associated with somatic mutations in the IDH1 or IDH2 genes. EXT1 mutations are associated with hereditary multiple exostoses.

Question 377

Topic: Upper Extremity Trauma

A 22-year-old male presents with a slow-growing, painless mass on his proximal humerus.

Imaging reveals a 2.5 cm surface lesion causing saucerization of the underlying cortex with a sclerotic margin. What is the definitive treatment to minimize local recurrence?

. Observation with serial radiographs
. Intralesional curettage and bone grafting
. Marginal excision including the underlying sclerotic cortical bone
. Wide en bloc resection with 2 cm margins
. Neoadjuvant radiation followed by excision

Correct Answer & Explanation

. Marginal excision including the underlying sclerotic cortical bone

Explanation

The clinical and radiographic presentation is classic for a periosteal chondroma. To minimize recurrence, treatment requires marginal excision that includes the underlying sclerotic cortex.

Question 378

Topic: Upper Extremity Trauma

A 70-year-old male develops a septic olecranon bursitis. He has no systemic signs of infection. Which of the following is the most appropriate initial management?

. Oral antibiotics and NSAIDs.
. Aspiration of the bursa and local steroid injection.
. Aspiration of the bursa and initiation of oral antibiotics.
. Surgical excision of the bursa.
. Intravenous antibiotics and immobilization.

Correct Answer & Explanation

. Aspiration of the bursa and initiation of oral antibiotics.

Explanation

For suspected septic olecranon bursitis without systemic signs of infection, the initial management typically involves aspiration of the bursa to confirm the diagnosis (Gram stain, cell count, culture) and initiation of empiric oral antibiotics covering common skin flora (e.g., Staphylococcus aureus). If the infection is severe, unresponsive to oral antibiotics, or if there are systemic signs, intravenous antibiotics and potentially surgical debridement/excision may be required. Steroid injection is contraindicated in septic bursitis. Surgical excision is usually reserved for chronic, recurrent, or refractory cases. IV antibiotics and immobilization might be too aggressive as initial management without systemic signs.

Question 379

Topic: Upper Extremity Trauma
A 25-year-old cyclist is struck by a vehicle and lands directly on the acromion of his shoulder. Radiographs reveal an acromioclavicular (AC) joint injury. The distal clavicle is displaced 200% superiorly relative to the acromion, and the coracoclavicular distance is more than double the contralateral side. According to the Rockwood classification, what type of injury is this?
. Type II
. Type III
. Type IV
. Type V
. Type VI

Correct Answer & Explanation

. Type III

Explanation

The Rockwood classification of AC joint injuries is based on the direction and degree of clavicular displacement. Type III involves 25-100% superior displacement. Type V involves 100-300% superior displacement of the distal clavicle, accompanied by severe disruption of the deltotrapezial fascia. Type IV is posterior displacement into or through the trapezius. Type VI is inferior displacement (subcoracoid or subacromial).

Question 380

Topic: Upper Extremity Trauma
A 28-year-old cyclist falls directly onto his shoulder. X-rays show a Rockwood Type III acromioclavicular (AC) joint separation. What defines a Type III injury?
. AC ligaments torn, CC ligaments intact, clavicle minimally displaced.
. AC ligaments torn, CC ligaments torn, clavicle displaced superiorly 25-100% of the normal CC distance.
. AC ligaments torn, CC ligaments torn, clavicle displaced posteriorly into the trapezius.
. AC ligaments torn, CC ligaments torn, clavicle displaced superiorly >100% of the normal CC distance.
. AC ligaments torn, CC ligaments intact, clavicle displaced inferiorly.

Correct Answer & Explanation

. AC ligaments torn, CC ligaments torn, clavicle displaced superiorly 25-100% of the normal CC distance.

Explanation

A Rockwood Type III AC joint separation involves tearing of both the acromioclavicular (AC) and coracoclavicular (CC) ligaments, with the distal clavicle displaced superiorly between 25% and 100% of the normal CC distance compared to the contralateral side.

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