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1. General Principles & Basic Science MCQs

Practice Set 441 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 8801

Topic: Surgical Anatomy & Approaches

During the deltopectoral approach to the shoulder, the cephalic vein is typically identified in the internervous plane between the deltoid and pectoralis major. To minimize the risk of bleeding from its major tributaries, the cephalic vein should ideally be retracted in which direction?

. Medially
. Laterally
. Superiorly
. Inferiorly
. Ligated routinely

Correct Answer & Explanation

. Laterally

Explanation

The cephalic vein is typically retracted laterally with the deltoid to preserve its major deltoid tributaries. Medial retraction risks avulsing these branches, leading to significant bleeding.

Question 8802

Topic: 1. General Principles & Basic Science

A 32-year-old competitive weightlifter feels a "pop" in his anterior axilla while performing a heavy bench press. Examination shows loss of the normal anterior axillary contour. In an acute complete rupture, which anatomic portion is most commonly avulsed and where is its normal insertion?

. Clavicular head; inserts deep to the sternal head
. Sternal head; inserts deep and proximal to the clavicular head
. Sternal head; inserts superficial and distal to the clavicular head
. Clavicular head; inserts superficial to the sternal head
. Costal head; inserts at the coracoid process

Correct Answer & Explanation

. Sternal head; inserts deep and proximal to the clavicular head

Explanation

Pectoralis major ruptures most commonly involve the sternal head avulsing from its humeral insertion. The sternal head twists 180 degrees to insert deep and proximal to the clavicular head on the humerus.

Question 8803

Topic: Physiology & Rehabilitation

A 28-year-old weightlifter feels a "pop" and tearing sensation in his anterior chest wall while performing a heavy bench press. Examination reveals loss of the anterior axillary fold and weakness in internal rotation. Which of the following is true regarding this injury?

. Most commonly involves the clavicular head of the pectoralis major
. Most commonly occurs at the musculotendinous junction
. Nonoperative treatment yields similar strength to surgical repair
. Avulsion of the sternocostal head from the humerus is the most common tear pattern
. MRI is contraindicated

Correct Answer & Explanation

. Avulsion of the sternocostal head from the humerus is the most common tear pattern

Explanation

Pectoralis major ruptures typically occur during eccentric contraction, such as a bench press, and most commonly involve avulsion of the sternocostal head from its humeral insertion. Surgical repair is recommended in active patients to restore strength.

Question 8804

Topic: 1. General Principles & Basic Science

A 32-year-old weightlifter feels a "pop" in his anterior axilla while performing a heavy bench press. Examination reveals an asymmetric axillary fold and weakness in internal rotation. MRI confirms a complete rupture of the pectoralis major tendon at its humeral insertion. Which of the following statements regarding this injury is true?

. The sternal head is primarily injured when the arm is extended and externally rotated.
. Nonoperative management yields equal strength outcomes compared to surgery in athletes.
. The clavicular head is most commonly injured.
. Repair should be delayed at least 6 months to allow tissue maturation.
. The musculocutaneous nerve is at highest risk during the standard deltopectoral approach for repair.

Correct Answer & Explanation

. The sternal head is primarily injured when the arm is extended and externally rotated.

Explanation

Pectoralis major ruptures typically occur during eccentric contraction, such as a bench press. The sternal head is under maximal tension when the arm is extended and externally rotated, making it the most frequently torn component.

Question 8805

Topic: Surgical Anatomy & Approaches

A 35-year-old recreational tennis player presents with vague posterior shoulder pain and paresthesias over the lateral deltoid. An MRI of the shoulder reveals isolated atrophy and fatty infiltration of the teres minor muscle. Which of the following structures is most likely compressed?

. Suprascapular nerve
. Long thoracic nerve
. Axillary nerve
. Radial nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Axillary nerve

Explanation

Quadrilateral space syndrome involves compression of the axillary nerve and posterior circumflex humeral artery. It classically presents with deltoid or teres minor weakness and is most specifically seen as isolated teres minor fatty infiltration on MRI.

Question 8806

Topic: 1. General Principles & Basic Science

A 19-year-old male is tackled during a rugby match and sustains a posterior sternoclavicular joint dislocation. He complains of shortness of breath and difficulty swallowing. Closed reduction in the operating room is planned. Which of the following surgical subspecialties MUST be immediately available during this procedure?

. Vascular surgery
. Cardiothoracic surgery
. Otorhinolaryngology (ENT)
. Neurosurgery
. Plastic surgery

Correct Answer & Explanation

. Cardiothoracic surgery

Explanation

Posterior sternoclavicular dislocations can compress or injure critical mediastinal structures, including the trachea, esophagus, and great vessels. Cardiothoracic or vascular surgery must be on standby during reduction in case of catastrophic vascular injury.

Question 8807

Topic: Surgical Anatomy & Approaches

A 28-year-old professional volleyball player presents with isolated weakness in external rotation of the dominant shoulder. Abduction strength is 5/5. MRI reveals a paralabral cyst. Where is the cyst most likely located and which nerve is compressed?

. Suprascapular notch; Suprascapular nerve
. Spinoglenoid notch; Suprascapular nerve
. Quadrilateral space; Axillary nerve
. Triangular interval; Radial nerve
. Spiral groove; Radial nerve

Correct Answer & Explanation

. Spinoglenoid notch; Suprascapular nerve

Explanation

Compression of the suprascapular nerve at the spinoglenoid notch affects only the infraspinatus, causing isolated external rotation weakness. Compression at the suprascapular notch would affect both the supraspinatus and infraspinatus, causing weakness in both abduction and external rotation.

Question 8808

Topic: 1. General Principles & Basic Science

A 48-year-old construction worker presents with a symptomatic Type II superior labrum anterior and posterior (SLAP) tear confirmed on MRI. He has failed 6 months of physical therapy. Based on recent literature, what is the recommended surgical management for this patient?

. Arthroscopic SLAP repair with suture anchors
. Open SLAP repair via a deltopectoral approach
. Arthroscopic debridement of the labrum without stabilization
. Biceps tenodesis
. Arthroscopic thermal capsulorrhaphy

Correct Answer & Explanation

. Biceps tenodesis

Explanation

In patients over 40 years old, biceps tenodesis has been shown to yield higher patient satisfaction, better functional outcomes, and lower revision rates compared to arthroscopic SLAP repair. SLAP repair in this demographic is associated with significant postoperative stiffness.

Question 8809

Topic: 1. General Principles & Basic Science

A 30-year-old bodybuilder experiences a sudden "pop" in his anterior axilla while performing a heavy bench press. Examination reveals loss of the anterior axillary fold and weakness in internal rotation. MRI confirms a rupture of the sternal head of the pectoralis major. Which of the following describes the correct anatomic relationship of the sternal head insertion?

. It inserts deep and proximal to the clavicular head on the humerus
. It inserts superficial and distal to the clavicular head on the humerus
. It inserts onto the coracoid process deep to the short head of the biceps
. It inserts onto the lesser tuberosity
. It blends with the conjoined tendon before inserting onto the humerus

Correct Answer & Explanation

. It inserts deep and proximal to the clavicular head on the humerus

Explanation

The pectoralis major tendon undergoes a 180-degree twist before inserting onto the lateral lip of the bicipital groove. The sternal head twists to insert deep and proximal to the clavicular head, placing it under maximal tension during the terminal eccentric phase of a bench press.

Question 8810

Topic: Surgical Anatomy & Approaches

A 35-year-old overhead athlete complains of poorly localized posterior shoulder pain and fatigue with throwing. MRI demonstrates isolated atrophy and fatty infiltration of the teres minor muscle. Compression of the neurovascular bundle in the quadrilateral space is suspected. What structures are at risk in this anatomic space?

. Suprascapular nerve and suprascapular artery
. Radial nerve and profound brachii artery
. Axillary nerve and posterior circumflex humeral artery
. Musculocutaneous nerve and anterior circumflex humeral artery
. Thoracodorsal nerve and thoracodorsal artery

Correct Answer & Explanation

. Axillary nerve and posterior circumflex humeral artery

Explanation

Quadrilateral space syndrome involves compression of the axillary nerve and posterior circumflex humeral artery. The space is bounded by the teres minor, teres major, long head of the triceps, and the surgical neck of the humerus.

Question 8811

Topic: 1. General Principles & Basic Science

A 28-year-old weightlifter felt a sudden "pop" in his anterior chest while performing a heavy bench press. Examination reveals ecchymosis over the anterior axillary fold and weakness in internal rotation and adduction. MRI confirms a complete rupture of the sternal head of the pectoralis major at its insertion. What is the most appropriate management?

. Sling immobilization for 6 weeks followed by strengthening
. Corticosteroid injection and immediate physical therapy
. Platelet-rich plasma (PRP) injection into the myotendinous junction
. Surgical repair of the tendon to the humeral insertion
. Tendon transfer using the latissimus dorsi

Correct Answer & Explanation

. Surgical repair of the tendon to the humeral insertion

Explanation

Pectoralis major ruptures most commonly occur at the sternal head insertion during eccentric loading. Surgical repair is recommended for young, active individuals to restore adduction and internal rotation strength and improve cosmetic contour.

Question 8812

Topic: 1. General Principles & Basic Science

An 18-year-old hockey player sustains a direct blow to his medial clavicle. He presents with severe pain, a palpable depression at the sternoclavicular joint, dysphagia, and mild dyspnea. What is the most appropriate next step in management?

. Discharge with a figure-of-eight brace and outpatient follow-up
. Immediate blind closed reduction in the emergency department
. CT scan of the chest and urgent closed reduction in the OR with cardiothoracic backup
. MRI of the brachial plexus to rule out nerve root avulsion
. Open reduction and internal fixation with Kirschner wires

Correct Answer & Explanation

. CT scan of the chest and urgent closed reduction in the OR with cardiothoracic backup

Explanation

Posterior sternoclavicular dislocations are orthopedic emergencies due to the risk of airway, vascular, or esophageal compression. A CT scan of the chest is diagnostic, and urgent reduction in the OR with cardiothoracic surgery backup is required.

Question 8813

Topic: Surgical Anatomy & Approaches

A 65-year-old female sustains a displaced 3-part proximal humerus fracture. Examination reveals decreased sensation over the lateral aspect of the deltoid. Which nerve is most likely injured, and what primary muscle function should be tested?

. Suprascapular nerve; external rotation
. Axillary nerve; shoulder abduction
. Musculocutaneous nerve; elbow flexion
. Radial nerve; wrist extension
. Long thoracic nerve; scapular protraction

Correct Answer & Explanation

. Axillary nerve; shoulder abduction

Explanation

The axillary nerve is frequently injured in proximal humerus fractures, presenting with numbness over the lateral deltoid (regimental badge area) and weakness in shoulder abduction due to deltoid denervation.

Question 8814

Topic: 1. General Principles & Basic Science

A 19-year-old male presents to the emergency department after a high-speed motor vehicle collision complaining of severe chest pain and dyspnea. Physical exam reveals a palpable depression over the medial clavicle. A CT scan confirms a posterior sternoclavicular dislocation. What is the most appropriate immediate management?

. Nonoperative management with a sling
. Closed reduction in the emergency department using procedural sedation
. Closed reduction in the operating room with cardiothoracic surgery on standby
. Immediate open reduction and internal fixation with a plate
. Excision of the medial clavicle

Correct Answer & Explanation

. Closed reduction in the operating room with cardiothoracic surgery on standby

Explanation

Posterior sternoclavicular dislocations are orthopedic emergencies due to the risk of compression to the trachea, esophagus, and great vessels. Closed reduction should be attempted in the operating room with cardiothoracic surgery available in case of vascular injury.

Question 8815

Topic: 1. General Principles & Basic Science

According to recent quantitative anatomic studies, which of the following arteries provides the dominant blood supply to the native humeral head?

. Anterior circumflex humeral artery
. Posterior circumflex humeral artery
. Suprascapular artery
. Thoracoacromial artery
. Circumflex scapular artery

Correct Answer & Explanation

. Posterior circumflex humeral artery

Explanation

While historically the anterior circumflex humeral artery was thought to be the primary supply, modern quantitative studies demonstrate that the posterior circumflex humeral artery provides the dominant blood supply to the humeral head.

Question 8816

Topic: 1. General Principles & Basic Science

A 32-year-old male weightlifter feels a pop in his anterior chest while bench pressing. Examination reveals a loss of the anterior axillary fold. If surgical repair is undertaken, the surgeon must recognize that the sternal head of the pectoralis major inserts in which orientation relative to the clavicular head?

. Proximal and anterior
. Distal and posterior
. Proximal and posterior
. Distal and anterior
. Directly medial

Correct Answer & Explanation

. Proximal and posterior

Explanation

The pectoralis major tendon undergoes a 180-degree twist before insertion. Consequently, the sternal head inserts proximal and posterior to the clavicular head on the lateral lip of the bicipital groove.

Question 8817

Topic: 1. General Principles & Basic Science

The superior transverse scapular ligament overlies the suprascapular notch. Which of the following correctly describes the anatomic relationship of the neurovascular structures at this level?

. Both the suprascapular artery and nerve pass superior to the ligament
. Both the suprascapular artery and nerve pass inferior to the ligament
. The suprascapular artery passes superior to the ligament, while the nerve passes inferiorly
. The suprascapular nerve passes superior to the ligament, while the artery passes inferiorly
. The suprascapular vein passes inferior to the ligament, with the artery and nerve passing superiorly

Correct Answer & Explanation

. The suprascapular artery passes superior to the ligament, while the nerve passes inferiorly

Explanation

At the suprascapular notch, the suprascapular artery passes over (superior to) the superior transverse scapular ligament, while the suprascapular nerve passes under (inferior to) the ligament. This is often remembered by the mnemonic "Army over, Navy under".

Question 8818

Topic: 1. General Principles & Basic Science

A 17-year-old male sustains a posterior sternoclavicular joint dislocation during a rugby match. He presents with mild dyspnea and dysphagia. What is the most appropriate next step in management?

. Immediate closed reduction in the emergency department under conscious sedation
. CT scan of the chest and consultation with a cardiothoracic surgeon prior to reduction
. Application of a figure-of-eight brace and early physical therapy
. Open reduction and internal fixation with K-wires
. MRI of the brachial plexus

Correct Answer & Explanation

. CT scan of the chest and consultation with a cardiothoracic surgeon prior to reduction

Explanation

Posterior sternoclavicular dislocations can fatally compress vital mediastinal structures. A CT scan is required to evaluate the position of the clavicle relative to the great vessels, and cardiothoracic surgery backup is mandated during reduction.

Question 8819

Topic: 1. General Principles & Basic Science

A 28-year-old bodybuilder experiences a sudden "pop" in his anterior axilla while performing a heavy bench press. Examination reveals loss of the normal anterior axillary fold. Which of the following best describes the most common anatomical location of a pectoralis major rupture?

. Clavicular head at the muscle belly
. Sternal head at the musculotendinous junction
. Clavicular head at its insertion on the humerus
. Sternal head at its tendinous insertion on the humerus
. Sternal head at the sternocostal origin

Correct Answer & Explanation

. Sternal head at its tendinous insertion on the humerus

Explanation

The vast majority of pectoralis major ruptures occur during eccentric loading (like heavy bench pressing) and involve the sternal head at its tendinous insertion on the humerus. Surgical repair is indicated in active patients to restore adduction and internal rotation strength.

Question 8820

Topic: Biology, Genetics & Bone Healing

Which of the following best describes the intracellular signaling pathway activated by Bone Morphogenetic Protein (BMP) to promote osteoblast differentiation?

. Activation of the Wnt/beta-catenin pathway
. Phosphorylation of Smad 1, 5, and 8
. Inhibition of RANKL expression
. Activation of the JAK/STAT pathway
. Binding to toll-like receptors (TLRs)

Correct Answer & Explanation

. Phosphorylation of Smad 1, 5, and 8

Explanation

BMPs bind to serine/threonine kinase receptors, leading to the phosphorylation of Smad 1, 5, and 8. These form a complex with Smad 4 and translocate to the nucleus to regulate gene expression for osteoblast differentiation.

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