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Surgical Anatomy & Approaches MCQs

Practice Set 67 of 102

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

Question 1321

Topic: Surgical Anatomy & Approaches

A 30-year-old male sustains a posterior hip dislocation in a motor vehicle collision. After closed reduction, he exhibits a foot drop and decreased sensation over the dorsum of his foot. Which nerve division is most likely injured?

. Femoral nerve
. Tibial division of sciatic nerve
. Peroneal division of sciatic nerve
. Obturator nerve
. Superior gluteal nerve

Correct Answer & Explanation

. Peroneal division of sciatic nerve

Explanation

Posterior hip dislocations most commonly injure the sciatic nerve. The common peroneal division is more susceptible to injury than the tibial division because of its more lateral position and tighter tethering at the fibular head.

Question 1322

Topic: Surgical Anatomy & Approaches

A 35-year-old male sustains an anterior column and anterior wall acetabular fracture. The surgeon elects to use an ilioinguinal approach. Which structure is located in the middle window of this surgical approach?

. Iliopsoas muscle and femoral nerve
. External iliac artery and vein
. Spermatic cord (or round ligament)
. Obturator artery and nerve
. Sciatic nerve

Correct Answer & Explanation

. External iliac artery and vein

Explanation

The ilioinguinal approach has three windows. The middle window contains the external iliac vessels, positioned between the iliopectineal fascia and the conjoint tendon.

Question 1323

Topic: Surgical Anatomy & Approaches

A primary THA is performed via the direct anterior approach. The internervous plane utilized is between muscles innervated by which of the following nerves?

. Superior gluteal and femoral nerves
. Superior gluteal and inferior gluteal nerves
. Femoral and obturator nerves
. Sciatic and superior gluteal nerves
. Inferior gluteal and obturator nerves

Correct Answer & Explanation

. Superior gluteal and femoral nerves

Explanation

The direct anterior approach uses the true internervous plane between the tensor fasciae latae (superior gluteal nerve) and the sartorius (femoral nerve). This preserves the abductor mechanism and minimizes denervation.

Question 1324

Topic: Surgical Anatomy & Approaches

A 35-year-old man presents with vague posterior shoulder pain and numbness over the lateral deltoid. An MRI of the shoulder demonstrates isolated atrophy of the teres minor. Which of the following structures is most likely compressed?

. Radial nerve and profunda brachii artery
. Suprascapular nerve and artery
. Axillary nerve and posterior circumflex humeral artery
. Musculocutaneous nerve and anterior circumflex humeral artery
. Thoracodorsal nerve and artery

Correct Answer & Explanation

. Axillary nerve and posterior circumflex humeral artery

Explanation

Quadrilateral space syndrome is caused by compression of the axillary nerve and posterior circumflex humeral artery. It classically leads to isolated teres minor atrophy and lateral shoulder paresthesia.

Question 1325

Topic: Surgical Anatomy & Approaches

During a Latarjet procedure, the coracoid process is transferred to the anterior glenoid. Which nerve is at greatest risk of injury during the coracoid preparation and transfer of the conjoined tendon?

. Axillary nerve
. Musculocutaneous nerve
. Suprascapular nerve
. Radial nerve
. Median nerve

Correct Answer & Explanation

. Musculocutaneous nerve

Explanation

The musculocutaneous nerve enters the coracobrachialis 5-8 cm distal to the coracoid process. It is tethered to the conjoined tendon and is at significant risk during retraction and transfer in a Latarjet procedure.

Question 1326

Topic: Surgical Anatomy & Approaches

A 32-year-old overhead athlete presents with poorly localized posterior shoulder pain and paresthesias over the lateral deltoid. Angiography demonstrates occlusion of the posterior circumflex humeral artery with the arm in abduction and external rotation. Which nerve is most likely compressed?

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

Correct Answer & Explanation

. Axillary nerve

Explanation

Quadrilateral space syndrome involves the compression of the axillary nerve and posterior circumflex humeral artery within the quadrilateral space. It is often caused by fibrous bands or hypertrophy of the adjacent teres minor muscle.

Question 1327

Topic: Surgical Anatomy & Approaches

A 32-year-old professional volleyball player presents with poorly localized posterior shoulder pain and paresthesias over the lateral deltoid. An MRI demonstrates isolated atrophy of the teres minor muscle. Which of the following structures is most likely being compressed?

. Suprascapular nerve in the spinoglenoid notch
. Axillary nerve in the quadrilateral space
. Radial nerve in the triangular interval
. Circumflex scapular artery in the triangular space
. Long thoracic nerve at the first rib

Correct Answer & Explanation

. Axillary nerve in the quadrilateral space

Explanation

Quadrilateral space syndrome involves compression of the axillary nerve and posterior humeral circumflex artery. It typically presents with localized teres minor atrophy, as the anterior branch of the axillary nerve supplying the deltoid may be spared.

Question 1328

Topic: Surgical Anatomy & Approaches

A 35-year-old man presents with vague posterior shoulder pain and numbness over the lateral aspect of the deltoid. MRI of the shoulder demonstrates isolated atrophy and fatty infiltration of the teres minor muscle. Which of the following structures is most likely compressed?

. Suprascapular nerve
. Axillary nerve and posterior circumflex humeral artery
. Radial nerve and profunda brachii artery
. Musculocutaneous nerve
. Spinal accessory nerve

Correct Answer & Explanation

. Axillary nerve and posterior circumflex humeral artery

Explanation

Quadrilateral space syndrome involves compression of the axillary nerve and the posterior circumflex humeral artery. It classically presents with teres minor atrophy, deltoid weakness, and lateral shoulder paresthesias.

Question 1329

Topic: Surgical Anatomy & Approaches

A 40-year-old male presents with vague posterior shoulder pain and weakness in external rotation. An MRI demonstrates fatty infiltration and atrophy isolated to the teres minor muscle. Which structure is most likely compressed?

. Suprascapular nerve
. Axillary nerve
. Radial nerve
. Musculocutaneous nerve
. Spinal accessory nerve

Correct Answer & Explanation

. Axillary nerve

Explanation

Quadrilateral space syndrome involves compression of the axillary nerve and posterior humeral circumflex artery. This typically results in isolated atrophy of the teres minor, though the deltoid may also be affected.

Question 1330

Topic: Surgical Anatomy & Approaches

A 24-year-old male undergoes a Latarjet procedure. Postoperatively, he exhibits profound weakness in elbow flexion and supination, along with numbness over the lateral forearm. Which nerve was most likely injured by vigorous retractor placement deep to the conjoined tendon?

. Axillary nerve
. Musculocutaneous nerve
. Radial nerve
. Median nerve
. Ulnar nerve

Correct Answer & Explanation

. Musculocutaneous nerve

Explanation

The musculocutaneous nerve enters the coracobrachialis approximately 3-8 cm distal to the coracoid tip. Vigorous medial retraction of the conjoined tendon during the Latarjet procedure places this nerve at high risk for a traction neuropathy.

Question 1331

Topic: Surgical Anatomy & Approaches

A 26-year-old elite volleyball player complains of vague posterior shoulder pain and fatigue with overhead activities. Physical exam reveals isolated atrophy of the teres minor. An MRI shows isolated fatty infiltration of the teres minor and a cystic structure in the quadrilateral space. Which vascular structure is most likely compressed alongside the affected nerve?

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

Correct Answer & Explanation

. Posterior humeral circumflex artery

Explanation

Quadrilateral space syndrome involves compression of the axillary nerve and the posterior humeral circumflex artery. This typically results in isolated teres minor atrophy and poorly localized posterior shoulder pain.

Question 1332

Topic: Surgical Anatomy & Approaches

A 35-year-old man sustains a midshaft humerus fracture resulting in an isolated radial nerve palsy. Electromyography at 4 weeks shows fibrillation potentials in the brachioradialis but no voluntary motor unit action potentials. What is the underlying pathophysiological process occurring at the distal axon?

. Neuropraxia with localized myelin conduction block
. Segmental demyelination without axonal disruption
. Wallerian degeneration due to axoplasmic flow disruption
. Retrograde chromatolysis at the anterior horn cell
. Schwann cell proliferation without axonal changes

Correct Answer & Explanation

. Wallerian degeneration due to axoplasmic flow disruption

Explanation

The presence of fibrillation potentials on electromyography indicates denervation, meaning axonal disruption has occurred (axonotmesis or neurotmesis). This disruption interrupts axoplasmic flow, leading to Wallerian degeneration of the distal nerve segment. Neuropraxia (focal demyelination) does not result in fibrillation potentials. Retrograde chromatolysis occurs in the neuronal cell body, not the distal axon.

Question 1333

Topic: Surgical Anatomy & Approaches
During a surgical approach to the humerus, the radial nerve is identified in the spiral groove. A traction injury occurs, resulting in axonal disruption but preservation of the endoneurium, perineurium, and epineurium. According to Seddon's classification, this type of injury is termed:
. Neuropraxia
. Axonotmesis
. Neurotmesis
. Sunderland Grade III
. Sunderland Grade IV

Correct Answer & Explanation

. Axonotmesis

Explanation

Seddon classified nerve injuries into three categories. Axonotmesis involves disruption of the axon and myelin sheath, but the surrounding connective tissue frameworks (endoneurium, perineurium, and epineurium) remain intact. This allows for Wallerian degeneration distally followed by potential guided regeneration. This corresponds to a Sunderland Grade II injury. Neuropraxia is a local conduction block without axonal disruption.

Question 1334

Topic: Surgical Anatomy & Approaches

A patient sustains a mid-shaft humerus fracture and presents with a dense radial nerve palsy. Electromyography (EMG) performed at 3 weeks shows fibrillation potentials and positive sharp waves in the brachioradialis. This finding is indicative of which of the following?

. Early reinnervation
. A neuropraxia injury
. Wallerian degeneration of the distal nerve segment
. Intact axons with a conduction block
. Successful collateral sprouting

Correct Answer & Explanation

. Wallerian degeneration of the distal nerve segment

Explanation

Fibrillation potentials and positive sharp waves on an EMG typically appear 2-3 weeks after a nerve injury and indicate denervation of the muscle fibers. This means the axon has been physically disrupted (as seen in axonotmesis or neurotmesis) and has undergone Wallerian degeneration distal to the site of injury. A neuropraxia (conduction block) leaves the axon intact and does not produce fibrillation potentials.

Question 1335

Topic: Surgical Anatomy & Approaches

A surgeon is performing a standard deltopectoral approach to the shoulder. Which of the following best defines the internervous plane utilized in this approach?

. Axillary nerve and Pectoral nerves
. Axillary nerve and Suprascapular nerve
. Musculocutaneous nerve and Radial nerve
. There is no true internervous plane in this approach
. Spinal accessory nerve and Axillary nerve

Correct Answer & Explanation

. Axillary nerve and Pectoral nerves

Explanation

The deltopectoral approach uses the internervous plane between the deltoid (innervated by the axillary nerve) and the pectoralis major (innervated by the medial and lateral pectoral nerves). This minimizes risk of denervating the anterior shoulder musculature.

Question 1336

Topic: Surgical Anatomy & Approaches

During an anterior intrapelvic (Stoppa) approach for an acetabular fracture, life-threatening hemorrhage occurs from an avulsed vascular anastomosis bridging over the superior pubic ramus. Which two vascular systems are connected by this "corona mortis"?

. Internal iliac and common femoral systems
. Obturator (internal iliac) and external iliac/inferior epigastric systems
. Superior gluteal and internal pudendal systems
. Inferior epigastric and internal pudendal systems
. Femoral and internal pudendal systems

Correct Answer & Explanation

. Obturator (internal iliac) and external iliac/inferior epigastric systems

Explanation

The corona mortis is a vascular connection between the obturator (internal iliac system) and the external iliac or inferior epigastric vessels. It crosses the superior pubic ramus and is highly vulnerable during anterior pelvic surgical approaches.

Question 1337

Topic: Surgical Anatomy & Approaches

A 35-year-old competitive weightlifter presents with vague posterior shoulder pain and paresthesias over the lateral deltoid, diagnosed as quadrangular space syndrome. What are the correct anatomical boundaries of this space?

. Teres minor (superior), teres major (inferior), long head of triceps (medial), surgical neck of humerus (lateral)
. Teres minor (superior), teres major (inferior), lateral head of triceps (medial), surgical neck of humerus (lateral)
. Infraspinatus (superior), teres minor (inferior), long head of triceps (medial), humerus (lateral)
. Subscapularis (superior), teres major (inferior), short head of biceps (medial), humerus (lateral)
. Teres major (superior), latissimus dorsi (inferior), long head of triceps (medial), humerus (lateral)

Correct Answer & Explanation

. Teres minor (superior), teres major (inferior), long head of triceps (medial), surgical neck of humerus (lateral)

Explanation

The quadrangular space is bounded superiorly by the teres minor, inferiorly by the teres major, medially by the long head of the triceps, and laterally by the surgical neck of the humerus. It contains the axillary nerve and posterior circumflex humeral artery.

Question 1338

Topic: Surgical Anatomy & Approaches

During a regional block in the femoral triangle prior to anterior cruciate ligament reconstruction, the anesthesiologist identifies the vascular structures to avoid intravascular injection. What is the anatomical relationship of the femoral nerve to the femoral artery in this region?

. Medial
. Lateral
. Anterior
. Posterior
. Superior

Correct Answer & Explanation

. Lateral

Explanation

Within the femoral triangle, structures are oriented from lateral to medial according to the mnemonic NAVEL: Nerve, Artery, Vein, Empty space, Lymphatics. Thus, the femoral nerve is strictly lateral to the femoral artery.

Question 1339

Topic: Surgical Anatomy & Approaches

When performing an anterior (Smith-Petersen) approach to the hip, what is the superficial internervous plane utilized?

. Sartorius and tensor fasciae latae
. Rectus femoris and gluteus medius
. Pectineus and adductor longus
. Tensor fasciae latae and gluteus medius
. Gracilis and adductor magnus

Correct Answer & Explanation

. Sartorius and tensor fasciae latae

Explanation

The superficial internervous plane of the anterior (Smith-Petersen) approach lies between the sartorius (femoral nerve) and the tensor fasciae latae (superior gluteal nerve). The deep plane is between the rectus femoris and the gluteus medius.

Question 1340

Topic: Surgical Anatomy & Approaches

A 28-year-old overhead athlete presents with poorly localized shoulder pain and deltoid weakness. An MRI reveals atrophy of the teres minor. Entrapment of the involved nerve typically occurs within a space bounded medially by which of the following structures?

. Humeral shaft
. Teres major
. Teres minor
. Long head of the triceps brachii
. Lateral head of the triceps brachii

Correct Answer & Explanation

. Humeral shaft

Explanation

Quadrilateral space syndrome involves compression of the axillary nerve and posterior circumflex humeral artery. The space is bounded medially by the long head of the triceps, laterally by the humeral shaft, superiorly by the teres minor, and inferiorly by the teres major.

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