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Surgical Anatomy & Approaches MCQs

Practice Set 26 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 501

Topic: Surgical Anatomy & Approaches

Recent literature regarding the fixation of posterior malleolus fractures in the setting of rotational ankle injuries emphasizes which of the following as the primary indication for open reduction and internal fixation of the posterior fragment?

. Fragment size greater than 25% of the articular surface
. Presence of an associated medial malleolus fracture
. Restoration of the incisura fibularis and syndesmotic stability
. Prevention of anterior talar translation
. Need to utilize a posterolateral surgical approach

Correct Answer & Explanation

. Restoration of the incisura fibularis and syndesmotic stability

Explanation

Historically, a fragment size >25-30% of the articular surface was the main indication for fixing the posterior malleolus. However, recent biomechanical and clinical studies emphasize that fixation of the posterior malleolus directly restores the posterior inferior tibiofibular ligament (PITFL) footprint, reconstituting the incisura fibularis and providing superior syndesmotic stability compared to trans-syndesmotic screws alone, regardless of the fragment's articular size.

Question 502

Topic: Surgical Anatomy & Approaches

A 22-year-old man presents with severe crush injury to his right forearm and is diagnosed with acute compartment syndrome. A volar approach for fasciotomy (extensile Henry approach) is planned. During deep dissection, which critical neurovascular structure must be carefully protected as it passes between the two heads of the pronator teres?

. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve
. Median nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Median nerve

Explanation

The median nerve classically runs between the humeral and ulnar heads of the pronator teres muscle in the proximal forearm. During the volar forearm fasciotomy (which utilizes the Henry approach extending from the distal humerus to the wrist), careful identification and release of the pronator teres aponeurosis and the FDS arch is necessary to thoroughly decompress the deep volar compartment and prevent secondary median nerve entrapment.

Question 503

Topic: Surgical Anatomy & Approaches

A 40-year-old man undergoes a single-incision anterior approach for repair of a complete acute distal biceps tendon rupture using a cortical button technique. Postoperatively, he complains of burning pain and numbness over the radial aspect of the mid-to-distal volar forearm. His motor function is completely intact. Which nerve was most likely injured during the surgical approach?

. Superficial radial nerve
. Posterior interosseous nerve
. Lateral antebrachial cutaneous nerve
. Medial antebrachial cutaneous nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Lateral antebrachial cutaneous nerve

Explanation

The lateral antebrachial cutaneous nerve (LABC), the terminal sensory branch of the musculocutaneous nerve, exits the deep fascia lateral to the biceps tendon and runs near the cephalic vein. It provides sensation to the radial half of the volar forearm. It is highly susceptible to traction or transection injury during the anterior single-incision approach to the distal biceps. The posterior interosseous nerve (PIN) is at risk during a two-incision approach or with deep retractors, but it provides motor innervation (which is intact here).

Question 504

Topic: Surgical Anatomy & Approaches
A 28-year-old male sustains a sharp complete transection of his radial nerve at the mid-humeral level. Within 24-48 hours post-injury, Wallerian degeneration begins. Which of the following best describes the pathophysiological process of Wallerian degeneration distal to the injury site?
. Schwann cells undergo rapid apoptosis and are completely cleared by local macrophages
. Axons and myelin degrade while macrophages clear the debris, and Schwann cells proliferate to form Bands of Büngner
. Complete loss of the endoneurial tubes occurs, requiring surgical grafting to direct regenerating axons
. Degeneration proceeds in a proximal-to-distal direction solely driven by osteoclastic enzyme release
. Retrograde degeneration extends entirely back to the spinal cord, leading to death of the anterior horn cell

Correct Answer & Explanation

. Axons and myelin degrade while macrophages clear the debris, and Schwann cells proliferate to form Bands of Büngner

Explanation

Wallerian degeneration occurs in the distal stump of a transected nerve. The axons and myelin sheath rapidly degrade, and macrophages migrate in to clear the debris. Crucially, the Schwann cells do not die; rather, they dedifferentiate, proliferate, and align to form longitudinal columns known as Bands of Büngner within the preserved endoneurial tubes. These bands secrete neurotrophic factors and provide a physical pathway to guide regenerating axonal sprouts from the proximal stump.

Question 505

Topic: Surgical Anatomy & Approaches
What nerve is at greatest risk when developing the superficial plane between the tensor fascia lata and sartorius during the anterior (Smith-Peterson) approach to the hip?
. Lateral femoral cutaneous
. Superior gluteal
. Inferior gluteal
. Obturator
. Femoral

Correct Answer & Explanation

. Lateral femoral cutaneous

Explanation

DISCUSSION: The lateral femoral cutaneous nerve pierces the fascia between the tensor fascia lata and the sartorius approximately 2.5 cm distal to the anterosuperior iliac spine and is at risk when the interval is defined. The superior gluteal and femoral nerves define the internervous plane between the tensor fascia lata and the sartorius and are not at risk for injury.

Question 506

Topic: Surgical Anatomy & Approaches

During an ilioinguinal or Stoppa approach for open reduction and internal fixation of an acetabular fracture, the surgeon must identify the 'corona mortis' to prevent catastrophic hemorrhage. This structure is classically defined as a vascular anastomosis between which two systems?

. External iliac (or inferior epigastric) and obturator
. Internal iliac and superior gluteal
. External pudendal and internal pudendal
. Inferior epigastric and femoral
. Obturator and internal pudendal

Correct Answer & Explanation

. External iliac (or inferior epigastric) and obturator

Explanation

The corona mortis (crown of death) is a highly variable but frequent vascular anastomosis between the external iliac system (or its branch, the inferior epigastric artery/vein) and the obturator system. It typically crosses over the superior pubic ramus at an average distance of 5-6 cm from the pubic symphysis and is at significant risk of iatrogenic injury during anterior pelvic approaches.

Question 507

Topic: Surgical Anatomy & Approaches

During open reduction and internal fixation of a severe proximal humerus fracture using an extended deltopectoral approach, the surgeon decides to split the deltoid muscle longitudinally to improve distal exposure. Which of the following structures is at greatest risk, and what is its approximate distance from the lateral tip of the acromion?

. Radial nerve; 10 cm
. Axillary nerve; 5 to 7 cm
. Musculocutaneous nerve; 3 to 5 cm
. Axillary nerve; 2 to 3 cm
. Radial nerve; 14 cm

Correct Answer & Explanation

. Axillary nerve; 5 to 7 cm

Explanation

The axillary nerve runs transversely across the deep surface of the deltoid muscle, typically 5 to 7 cm distal to the lateral tip of the acromion. A longitudinal deltoid split should not extend more distal than this threshold to avoid denervating the anterior portion of the deltoid.

Question 508

Topic: Surgical Anatomy & Approaches

During a modified Stoppa approach for the treatment of an anterior column acetabular fracture, the surgeon must carefully identify and potentially ligate the 'corona mortis' to prevent catastrophic hemorrhage. This structure represents a vascular anastomosis between which two systems?

. Internal pudendal and superior gluteal vessels
. Inferior epigastric (or external iliac) and obturator vessels
. Superior epigastric and internal pudendal vessels
. Deep circumflex iliac and internal pudendal vessels
. Inferior gluteal and obturator vessels

Correct Answer & Explanation

. Inferior epigastric (or external iliac) and obturator vessels

Explanation

The corona mortis ('crown of death') is a critical vascular anastomosis connecting the external iliac or inferior epigastric system to the obturator system. It traverses the superior pubic ramus and is highly vulnerable to iatrogenic injury during the intrapelvic (modified Stoppa or ilioinguinal) approach to the acetabulum.

Question 509

Topic: Surgical Anatomy & Approaches

A 35-year-old female sustains a Bryan-Morrey Type I capitellum fracture. The surgeon elects to perform an open reduction and internal fixation utilizing the Kaplan approach. Which inter-nervous/inter-muscular interval is utilized in this approach, and which nerve is most at risk during distal dissection?

. Interval between ECU and Anconeus; PIN at risk
. Interval between ECRB and EDC; PIN at risk
. Interval between ECRL and ECRB; Radial nerve at risk
. Interval between Brachioradialis and Triceps; Radial nerve at risk
. Interval between FCU and FCR; Ulnar nerve at risk

Correct Answer & Explanation

. Interval between ECRB and EDC; PIN at risk

Explanation

The Kaplan approach to the lateral elbow utilizes the interval between the extensor carpi radialis brevis (ECRB) and the extensor digitorum communis (EDC). During distal dissection, the posterior interosseous nerve (PIN) is at risk as it courses through the supinator muscle. The Kocher approach uses the interval between the anconeus and the extensor carpi ulnaris (ECU).

Question 510

Topic: Surgical Anatomy & Approaches
A 35-year-old male sustains a posterior hip dislocation following a high-speed motor vehicle collision. CT imaging post-reduction reveals an associated fracture of the femoral head that is located inferior to the fovea capitis. According to the Pipkin classification, what type of fracture is this, and what is the preferred surgical approach if open reduction and internal fixation is indicated?
. Type I; Anterior approach (Smith-Petersen or Hueter)
. Type II; Anterior approach (Smith-Petersen or Hueter)
. Type I; Posterior approach (Kocher-Langenbeck)
. Type III; Posterior approach (Kocher-Langenbeck)
. Type IV; Surgical hip dislocation (Ganz approach)

Correct Answer & Explanation

. Type I; Anterior approach (Smith-Petersen or Hueter)

Explanation

According to the Pipkin classification, a Type I fracture involves the femoral head inferior to the fovea capitis (non-weight-bearing portion). If ORIF is indicated (e.g., irreducible fragment, joint incongruity), an anterior approach (Smith-Petersen or Hueter) is preferred. A posterior approach in the setting of a posterior dislocation further jeopardizes the already tenuous medial femoral circumflex artery (MFCA) blood supply, significantly increasing the risk of avascular necrosis.

Question 511

Topic: Surgical Anatomy & Approaches

During a modified Stoppa (anterior intrapelvic) approach for fixation of an anterior column acetabular fracture, significant hemorrhage occurs when dissecting superior to the superior pubic ramus. Which vascular anastomosis was most likely injured?

. External iliac artery to the internal pudendal artery
. Deep circumflex iliac artery to the obturator artery
. Inferior epigastric artery (or external iliac) to the obturator artery
. Superior gluteal artery to the internal pudendal artery
. Internal pudendal artery to the inferior vesicular artery

Correct Answer & Explanation

. Inferior epigastric artery (or external iliac) to the obturator artery

Explanation

The 'corona mortis' (crown of death) is a vascular anastomosis between the obturator system (internal iliac) and the external iliac system (most commonly the inferior epigastric artery or vein). It typically crosses the superior pubic ramus at an average distance of 5-6 cm from the pubic symphysis. Dissection in this area during ilioinguinal or modified Stoppa approaches must be done meticulously to identify and ligate these vessels to prevent life-threatening hemorrhage.

Question 512

Topic: Surgical Anatomy & Approaches

During an anterior intrapelvic (modified Stoppa) approach for acetabular fracture fixation, significant arterial bleeding is encountered near the superior pubic ramus. This bleeding is most likely originating from an anastomosis between which two vessels?

. Internal pudendal and superior gluteal arteries
. External iliac and obturator arteries
. Internal iliac and inferior epigastric arteries
. External iliac and inferior gluteal arteries
. Obturator and internal pudendal arteries

Correct Answer & Explanation

. External iliac and obturator arteries

Explanation

The corona mortis is a vascular anastomosis between the external iliac (or inferior epigastric) and the obturator vessels. It is located over the superior pubic ramus and is highly vulnerable during the anterior intrapelvic approach.

Question 513

Topic: Surgical Anatomy & Approaches
A 30-year-old man presents with a posterior hip dislocation and a femoral head fracture located superior to the fovea capitis. According to the Pipkin classification, what type of fracture is this, and what is the preferred surgical approach for fixation?
. Pipkin I, anterior approach
. Pipkin I, posterior approach
. Pipkin II, anterior approach
. Pipkin II, posterior approach
. Pipkin III, lateral approach

Correct Answer & Explanation

. Pipkin II, anterior approach

Explanation

A femoral head fracture superior to the fovea capitis (involving the primary weight-bearing portion) is a Pipkin Type II fracture. The anterior (Smith-Petersen) approach is generally preferred for optimal visualization and perpendicular screw fixation of anterior/superior femoral head fragments.

Question 514

Topic: Surgical Anatomy & Approaches

When performing the extended volar (Henry) approach to the distal radius and forearm, the surgeon exploits the internervous plane in the proximal forearm between the flexor carpi radialis (FCR) and the brachioradialis. This represents a safe interval between the territories of which two nerves?

. Median and Ulnar nerves
. Radial and Musculocutaneous nerves
. Median and Radial nerves
. Anterior Interosseous and Radial nerves
. Radial and Ulnar nerves

Correct Answer & Explanation

. Median and Radial nerves

Explanation

The volar Henry approach to the radius utilizes the internervous plane between the brachioradialis (innervated by the radial nerve) and the flexor carpi radialis (innervated by the median nerve). Retracting the brachioradialis laterally and the FCR medially provides access to the pronator teres and flexor pollicis longus, beneath which the radius lies.

Question 515

Topic: Surgical Anatomy & Approaches

During a primary THA using the direct anterior (Smith-Petersen) approach, the surgeon develops the internervous plane between the sartorius and the tensor fasciae latae. Which of the following nerves is at greatest risk of injury during this superficial dissection?

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

Correct Answer & Explanation

. Lateral femoral cutaneous nerve

Explanation

The lateral femoral cutaneous nerve (LFCN) crosses the anterior thigh and is at significant risk of injury during the superficial dissection of the direct anterior approach. The internervous plane is between the sartorius (femoral n.) and the tensor fasciae latae (superior gluteal n.).

Question 516

Topic: Surgical Anatomy & Approaches

Figure 25 shows an arthroscopic thermal capsular shrinkage device being used in the anterior inferior quadrant of a patient with a subluxating shoulder. Which of the following neurologic complications is most frequently reported with this technique?

Anatomy Board Review 2002: High-Yield MCQs (Set 2) - Figure 26

. Axillary nerve dysesthesia
. Axillary nerve motor partial paralysis
. Suprascapular nerve neurapraxia
. Musculocutaneous nerve neurapraxia
. Radial nerve sensory dysesthesia

Correct Answer & Explanation

. Axillary nerve dysesthesia

Explanation

The axillary nerve lies within millimeters of the anterior inferior capsule. The inferior capsule is of varying thickness, and thermal energy used in shortening the ligament can cause damage to the sensory fibers of the axillary nerve. Clinically, this is manifested as a burnt skin sensation in the axillary nerve distribution area. The motor branch of the axillary nerve is usually spared. The suprascapular nerve and the radial nerve are far from the shrinkage zone. The musculocutaneous nerve, frequently at risk with open procedures, lies well anterior. Fanton GS: Arthroscopic electrothermal surgery of the shoulder. Op Tech Sports Med 1998;6:157-160.

Question 517

Topic: Surgical Anatomy & Approaches

A 68-year-old man reports a 1-year history of debilitating neck pain without neurologic symptoms. History reveals a C5-6 anterior diskectomy and bone grafting 10 years ago that provided good relief of arm and neck pain. Radiographs show evidence of fibrous union at C5-6, spondylotic disk narrowing at C4-5 and C6-7, and a fixed 2-mm subluxation at C3-4. Examination reveals cervical stiffness and discomfort at the extremes of movement. His neurologic examination is normal. Treatment should now consist of

Spine Surgery 2006 Practice Questions: Set 1 (Solved) - Figure 4

. posterior fusion at C3-C7.
. anterior fusion at C3-7 with plate fixation through the same scar.
. anterior fusion at C3-7 with plate fixation through a right-sided incision.
. an epidural steroid injection.
. patient education, exercise, and nonnarcotic medication.

Correct Answer & Explanation

. patient education, exercise, and nonnarcotic medication.

Explanation

Axial pain can be difficult to manage. Pain management is not always successful, and surgical approaches may provide disappointing results unless there is discrete pathology. Whereas planning of a surgical approach should consider prior approaches and preexisting laryngeal dysfunction, no compelling case for surgical intervention can be made for this patient. Therefore, management should consist of patient education, exercise, and nonnarcotic medication. Ahn NU, Ahn UM, Andersson GB, et al: Operative treatment of the patient with neck pain. Phys Med Rehabil Clin N Am 2003;14:675-692. Algers G, Pettersson K, Hildingsson C, et al: Surgery for chronic symptoms after whiplash injury: Follow-up of 20 cases. Acta Orthop Scand 1993;64:654-656.

Question 518

Topic: Surgical Anatomy & Approaches

A 32-year-old man has a closed oblique displaced fracture at the junction of the lower and middle third of the humeral shaft and a complete radial nerve palsy. Closed reduction is performed and is felt to be acceptable. Management of the radial nerve palsy should consist of

. exploration and repair of the radial nerve if clinical findings or electromyographic studies show no improvement at 2 to 3 weeks.
. exploration and repair of the radial nerve if clinical findings or electromyographic studies show no improvement at 14 weeks.
. transfer of the pronator teres to the extensor carpi radialis brevis if clinical findings or electromyographic studies show no improvement at 14 weeks.
. immediate exploration and repair of the radial nerve, along with internal fixation with a plate and screws.
. immediate exploration and repair of the radial nerve, along with internal fixation with an intramedullary nail.

Correct Answer & Explanation

. exploration and repair of the radial nerve if clinical findings or electromyographic studies show no improvement at 14 weeks.

Explanation

In patients who have radial nerve dysfunction associated with a closed humeral fracture, nerve function usually will return to normal without surgical exploration. If clinical findings or electromyographic studies show no improvement at 3 months, surgical exploration and repair can be performed. Tendon transfers are performed if nerve repair is deemed unsuccessful. Pollock FH, Drake D, Bovill EG, et al: Treatment of radial neuropathy associated with fractures of the humerus. J Bone Joint Surg Am 1981;63:239-243.

Question 519

Topic: Surgical Anatomy & Approaches

A 35-year-old man has profound deltoid weakness after sustaining a traumatic anterior shoulder dislocation 6 weeks ago. Electromyographic (EMG) studies confirm an axillary nerve injury. Follow-up examination at 3 months reveals no recovery of function. What is the best course of action?

. Surgical repair of the Bankart lesion
. Exploration of the axillary nerve
. MRI neurography
. Repeat EMG studies
. Continued observation and physical therapy

Correct Answer & Explanation

. Repeat EMG studies

Explanation

Documenting the status of recovery at this time is appropriate; therefore, repeat EMG studies should be conducted to check for early signs of reinnervation. Timing of nerve exploration in this setting is debated, with authors suggesting exploration if there is no sign of recovery at 6 to 9 months. Perlmutter GS: Axillary nerve injury. Clin Orthop 1999;368:28-36. Artico M, Salvati M, D'Andrea V, et al: Isolated lesions of the axillary nerves: Surgical treatment and outcome in twelve cases. Neurosurgery 1991;29:697-700. Vissar CP, Coene LN, Brand R, et al: The incidence of nerve injury in anterior dislocation of the shoulder and its influence on functional recovery: A prospective clinical and EMG study. J Bone Joint Surg Br 1999;81:679-685.

Question 520

Topic: Surgical Anatomy & Approaches

An adult patient has a closed humeral fracture that was treated nonsurgically and a concomitant radial nerve injury. Six weeks after injury, electromyography shows no evidence of recovery. Management should now consist of

. exploration and neurolysis/repair.
. MRI of the arm.
. functional electrical stimulation.
. radial nerve tendon transfers.
. observation.

Correct Answer & Explanation

. observation.

Explanation

In patients with radial nerve injuries with closed humeral fractures, it has been reported that 85% to 95% spontaneously recover. Based on this premise, most surgeons favor expectant management of these injuries. Even if there is no evidence of recovery at 6 weeks, repeat electromyography at 12 weeks is advocated. If there is no clinical or electromyographic signs of recovery at 6 months, exploration is recommended. If the nerve is in continuity at the time of exploration, nerve action potentials are useful in helping determine the need for neurolysis, excision, and grafting, or if excision and repair is the best option. Pollock FH, Drake D, Bovill EG, et al: Treatment of radial neuropathy associated with fractures of the humerus. J Bone Joint Surg Am 1981;63:239-243.

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