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Surgical Anatomy & Approaches MCQs

Practice Set 81 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 1601

Topic: Surgical Anatomy & Approaches

A surgeon is performing an anterior (Smith-Petersen) approach to the hip. The superficial surgical interval lies between two muscles innervated by different nerves. What are the respective nerve innervations of these two muscles?

. Femoral nerve and Superior gluteal nerve
. Femoral nerve and Obturator nerve
. Superior gluteal nerve and Inferior gluteal nerve
. Sciatic nerve and Superior gluteal nerve
. Femoral nerve and Sciatic nerve

Correct Answer & Explanation

. Femoral nerve and Superior gluteal nerve

Explanation

The anterior (Smith-Petersen) approach utilizes a superficial internervous plane between the Sartorius (innervated by the femoral nerve) and the Tensor Fasciae Latae (innervated by the superior gluteal nerve). The deep plane lies between the Rectus Femoris (femoral nerve) and Gluteus Medius (superior gluteal nerve).

Question 1602

Topic: Surgical Anatomy & Approaches

A 30-year-old male sustains a midshaft humerus fracture resulting in a complete radial nerve palsy. Closed reduction is performed. Based on the expected rate of axonal regeneration following Wallerian degeneration, what is the approximate rate of nerve recovery once the distal segment is prepared?

. 0.1 mm per day
. 1 mm per day
. 5 mm per day
. 1 cm per day
. 5 cm per day

Correct Answer & Explanation

. 1 mm per day

Explanation

Following a nerve injury (axonotmesis) and subsequent Wallerian degeneration of the distal segment, axonal regeneration occurs at a relatively constant rate of approximately 1 mm per day (or 1 inch per month) after an initial delay period.

Question 1603

Topic: Surgical Anatomy & Approaches

A patient sustains a closed midshaft humerus fracture with an associated radial nerve palsy. According to Seddon's classification, if the nerve injury is characterized by axonal disruption with an intact endoneurium, what is the specific classification of this injury?

. Neurapraxia
. Axonotmesis
. Neurotmesis
. Sunderland Grade IV
. Sunderland Grade V

Correct Answer & Explanation

. Axonotmesis

Explanation

Axonotmesis involves disruption of the axon and myelin sheath, but preservation of the supporting connective tissue framework (endoneurium, perineurium, and epineurium). This allows for potential spontaneous nerve regeneration along the intact endoneurial tubes at a rate of 1 mm/day.

Question 1604

Topic: Surgical Anatomy & Approaches
Following a severe crush injury to the arm resulting in a Sunderland Grade IV injury of the radial nerve, Wallerian degeneration ensues. Which of the following best describes the classical process of Wallerian degeneration?
. Degeneration of the axon extending proximally from the injury site all the way to the anterior horn cell
. Anterograde degeneration of the axon and surrounding myelin sheath distal to the site of injury
. Primary demyelination of the nerve with complete preservation of the underlying axoplasm
. Programmed apoptosis of the Schwann cells predominantly at the injury site
. Retrograde chromatolysis without any visible morphological changes in the distal axon

Correct Answer & Explanation

. Anterograde degeneration of the axon and surrounding myelin sheath distal to the site of injury

Explanation

Wallerian degeneration is the active process of anterograde degeneration of the axon and its myelin sheath distal to the site of a severe nerve injury (axotmesis or neurotmesis). Macrophages and Schwann cells subsequently clear the debris, leaving endoneurial tubes (bands of Büngner) to guide potential regenerating axons.

Question 1605

Topic: Surgical Anatomy & Approaches

During an anterior intrapelvic (modified Stoppa) approach for a complex acetabular fracture, massive hemorrhage occurs while dissecting bluntly over the superior pubic ramus. This bleeding most likely originates from an anastomosis between which two vascular systems?

. Internal pudendal and inferior gluteal systems
. External iliac and obturator systems
. Superior gluteal and lateral sacral systems
. Internal iliac and deep circumflex iliac systems
. Femoral and medial circumflex femoral systems

Correct Answer & Explanation

. External iliac and obturator systems

Explanation

The 'corona mortis' is a critical vascular anastomosis between the external iliac (or inferior epigastric) and obturator vessels. It crosses the superior pubic ramus and is highly vulnerable during the modified Stoppa or ilioinguinal approaches.

Question 1606

Topic: Surgical Anatomy & Approaches

A 32-year-old unrestrained driver presents with a shortened, adducted, and internally rotated right leg following a motor vehicle accident. Post-reduction CT shows a 3 mm incarcerated intra-articular acetabular fragment. What is the most critical rationale for urgent surgical extraction?

. To prevent sciatic nerve stretch palsy
. To mitigate rapid onset of chondral damage and avascular necrosis
. To allow for earlier weight-bearing rehabilitation
. To prevent deep vein thrombosis formation in the iliac vein
. To avoid the development of heterotopic ossification

Correct Answer & Explanation

. To mitigate rapid onset of chondral damage and avascular necrosis

Explanation

Incarcerated intra-articular fragments following a posterior hip dislocation prevent congruent reduction, creating excessive focal capsular tension and mechanical joint destruction. Urgent arthrotomy or arthroscopy is required to prevent rapid chondrolysis and minimize AVN risk.

Question 1607

Topic: Surgical Anatomy & Approaches

A surgeon performs an anterolateral approach to the distal humerus to plate a shaft fracture. During deep dissection separating the brachialis from the brachioradialis, which nerve-artery combination must be carefully identified and protected?

. Median nerve and brachial artery
. Ulnar nerve and superior ulnar collateral artery
. Radial nerve and radial recurrent artery
. Musculocutaneous nerve and anterior circumflex humeral artery
. Axillary nerve and posterior circumflex humeral artery

Correct Answer & Explanation

. Radial nerve and radial recurrent artery

Explanation

In the anterolateral approach to the distal humerus, the interval is between the brachialis (musculocutaneous/radial nerves) and brachioradialis (radial nerve). The radial nerve and the accompanying radial recurrent artery must be protected here.

Question 1608

Topic: Surgical Anatomy & Approaches

During a minimally invasive plate osteosynthesis (MIPO) via an anterior approach for a humeral shaft fracture, the plate is passed submuscularly beneath the brachialis. Which structure is at greatest risk of impingement if the plate drifts excessively medial in the mid-arm?

. Radial nerve
. Musculocutaneous nerve
. Brachial artery
. Profunda brachii artery
. Axillary nerve

Correct Answer & Explanation

. Brachial artery

Explanation

In an anterior MIPO approach to the humerus, medial deviation of the plate or instrumentation risks injury to the brachial artery and median nerve, which course medial to the biceps and brachialis muscles.

Question 1609

Topic: Surgical Anatomy & Approaches

During a lateral approach to the distal humerus, the surgeon must identify and protect the radial nerve. Anatomically, at what average distance from the lateral epicondyle does the radial nerve pierce the lateral intermuscular septum to enter the anterior compartment of the arm?

. 3 cm
. 5 cm
. 10 cm
. 15 cm
. 20 cm

Correct Answer & Explanation

. 10 cm

Explanation

The radial nerve pierces the lateral intermuscular septum to pass from the posterior to the anterior compartment approximately 10 cm (range 9-12 cm) proximal to the lateral epicondyle. Identifying this precise anatomic landmark is crucial for safe distal humerus exposures.

Question 1610

Topic: Surgical Anatomy & Approaches

A patient undergoes an ilioinguinal approach for an anterior column acetabular fracture. Severe hemorrhage is encountered over the posterior aspect of the superior pubic ramus. This bleeding is most likely originating from the Corona Mortis, which is an anastomosis between which two vascular systems?

. Internal iliac and internal pudendal
. External iliac and obturator
. Femoral and superficial epigastric
. Internal iliac and superior gluteal
. Superior vesical and inferior epigastric

Correct Answer & Explanation

. External iliac and obturator

Explanation

The Corona Mortis is a life-threatening vascular anastomosis between the external iliac (or inferior epigastric) system and the obturator (internal iliac) system. It is reliably found traversing the posterior aspect of the superior pubic ramus, averaging 5 cm from the symphysis pubis.

Question 1611

Topic: Surgical Anatomy & Approaches

A 30-year-old male sustains a posterior hip dislocation. Post-reduction examination reveals complete weakness in ankle dorsiflexion and great toe extension, but normal ankle plantar flexion. Which specific nerve structure is injured, and what is its most common anatomic relationship to the piriformis muscle?

. Tibial division; passes superior to the piriformis
. Peroneal division; passes superior to or through the piriformis
. Tibial division; passes inferior to the piriformis
. Peroneal division; passes inferior to the piriformis
. Femoral nerve; passes anterior to the piriformis

Correct Answer & Explanation

. Tibial division; passes inferior to the piriformis

Explanation

Posterior hip dislocations most commonly selectively injure the common peroneal division of the sciatic nerve. Anatomically, in the majority of the population (approx. 85%), both divisions of the sciatic nerve exit the pelvis together inferior to the piriformis muscle.

Question 1612

Topic: Surgical Anatomy & Approaches

Which of the following vessels provides the primary blood supply to the adult femoral head and is most at risk during a posterior approach to the hip?

. Ascending branch of the lateral femoral circumflex artery
. Deep branch of the medial femoral circumflex artery
. Artery of the ligamentum teres
. Inferior gluteal artery
. Superior gluteal artery

Correct Answer & Explanation

. Deep branch of the medial femoral circumflex artery

Explanation

The deep branch of the medial femoral circumflex artery (MFCA) provides the predominant blood supply to the adult femoral head. It courses posterior to the femoral neck, making it highly vulnerable during posterior surgical approaches and posterior hip dislocations.

Question 1613

Topic: Surgical Anatomy & Approaches

A patient presents to the emergency department after a motor vehicle collision with a right hip dislocation. The affected leg is shortened, flexed, adducted, and internally rotated. Which nerve is at highest risk of injury in this scenario?

. Femoral nerve
. Sciatic nerve
. Obturator nerve
. Superior gluteal nerve
. Lateral femoral cutaneous nerve

Correct Answer & Explanation

. Sciatic nerve

Explanation

The clinical presentation describes a posterior hip dislocation, which accounts for up to 90% of all hip dislocations. The sciatic nerve, particularly its peroneal division, is positioned immediately posterior to the hip joint and is at highest risk of traumatic injury.

Question 1614

Topic: Surgical Anatomy & Approaches

In the posterior compartment of the arm, the profunda brachii (deep brachial) artery travels in intimate association with which of the following nerves?

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

Correct Answer & Explanation

. Radial nerve

Explanation

The profunda brachii artery travels alongside the radial nerve through the spiral groove in the posterior compartment of the arm. Both structures are vulnerable to injury in midshaft humerus fractures and lateral surgical approaches.

Question 1615

Topic: Surgical Anatomy & Approaches

During surgical approaches to the anterior acetabulum, the "Corona Mortis" is a significant vascular hazard. Which of the following best describes this structure?

. An anastomosis between the external iliac and internal iliac venous systems
. An anastomosis between the obturator vessels and the external iliac or inferior epigastric vessels
. An aberrant branch of the internal pudendal artery crossing the symphysis
. A circumflex vascular ring traversing directly over the anterior femoral neck
. A high-flow venous plexus located within the space of Retzius

Correct Answer & Explanation

. An anastomosis between the obturator vessels and the external iliac or inferior epigastric vessels

Explanation

The corona mortis (crown of death) is a highly variable vascular anastomosis between the obturator system and the external iliac or inferior epigastric vessels. It crosses over the superior pubic ramus and is at severe risk of catastrophic bleeding during anterior intrapelvic approaches.

Question 1616

Topic: Surgical Anatomy & Approaches

During a standard deltopectoral approach to the proximal humerus, meticulous retraction must be used near the coracoid process. Where does the axillary nerve course relative to the conjoint tendon?

. Anterior to the conjoint tendon
. Superior to the conjoint tendon
. Inferior to the conjoint tendon
. Medial to the conjoint tendon
. Directly through the substance of the conjoint tendon

Correct Answer & Explanation

. Inferior to the conjoint tendon

Explanation

The axillary nerve courses inferior to the conjoint tendon as it travels from the posterior cord of the brachial plexus toward the quadrilateral space. Aggressive retraction inferior to the coracoid process places the axillary nerve at significant risk for neuropraxia.

Question 1617

Topic: Surgical Anatomy & Approaches

The anterior (Smith-Petersen) approach to the hip is a true internervous plane. Which two muscles form the superficial surgical interval for this approach?

. Gluteus medius and Tensor fasciae latae
. Sartorius and Tensor fasciae latae
. Gluteus maximus and Gluteus medius
. Rectus femoris and Vastus lateralis
. Pectineus and Adductor longus

Correct Answer & Explanation

. Sartorius and Tensor fasciae latae

Explanation

The superficial internervous plane of the anterior (Smith-Petersen) approach is between the sartorius, which is innervated by the femoral nerve, and the tensor fasciae latae (TFL), which is innervated by the superior gluteal nerve.

Question 1618

Topic: Surgical Anatomy & Approaches

During a posterior approach to the humerus for internal fixation of a distal third shaft fracture, the surgeon visualizes the radial nerve. Which vascular structure runs directly with the radial nerve in the spiral groove?

. Anterior circumflex humeral artery
. Brachial artery
. Profunda brachii artery
. Superior ulnar collateral artery
. Radial collateral artery

Correct Answer & Explanation

. Profunda brachii artery

Explanation

The profunda brachii (deep brachial) artery travels with the radial nerve through the spiral groove of the posterior humerus. It subsequently divides into the radial collateral and middle collateral arteries.

Question 1619

Topic: Surgical Anatomy & Approaches

During an anterior intrapelvic (modified Stoppa) approach for an acetabular fracture, significant hemorrhage occurs near the superior pubic ramus. This is most likely due to injury to the "corona mortis", which is an anastomosis between which two vascular systems?

. External iliac and obturator
. Internal iliac and inferior pudendal
. Superior gluteal and internal pudendal
. Inferior epigastric and superficial circumflex iliac
. Femoral and medial femoral circumflex

Correct Answer & Explanation

. External iliac and obturator

Explanation

The "corona mortis" is a vascular anastomosis between the external iliac (or inferior epigastric) and the obturator vessels. It lies on the posterior aspect of the superior pubic ramus and is highly vulnerable during anterior intrapelvic approaches.

Question 1620

Topic: Surgical Anatomy & Approaches

When performing a Smith-Petersen (anterior) approach to the hip, which internervous plane is utilized for the superficial dissection?

. Femoral and Superior Gluteal nerves
. Femoral and Obturator nerves
. Sciatic and Inferior Gluteal nerves
. Superior Gluteal and Inferior Gluteal nerves
. Femoral and Sciatic nerves

Correct Answer & Explanation

. Femoral and Superior Gluteal nerves

Explanation

The Smith-Petersen approach utilizes the superficial internervous plane between the sartorius (innervated by the femoral nerve) and the tensor fasciae latae (innervated by the superior gluteal nerve).

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