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Surgical Anatomy & Approaches MCQs

Practice Set 82 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 1621

Topic: Surgical Anatomy & Approaches

A 35-year-old sustains a closed, spiral fracture of the distal third of the humeral shaft. Initial exam shows intact radial nerve function. Following closed reduction and splinting, the patient develops a complete wrist drop. What is the most appropriate next step in management?

. Immediate surgical exploration and internal fixation
. Observation and functional bracing
. Electromyography at 3 weeks
. Ultrasound of the radial nerve
. Casting in extension

Correct Answer & Explanation

. Immediate surgical exploration and internal fixation

Explanation

A secondary radial nerve palsy that develops after closed reduction of a humeral shaft fracture is an indication for immediate surgical exploration. This presentation suggests the nerve may have become entrapped within the fracture site during the reduction maneuver.

Question 1622

Topic: Surgical Anatomy & Approaches

A 40-year-old male sustains a traumatic posterior hip dislocation. Following closed reduction, he exhibits foot drop and an inability to actively extend his great toe. Which division of the sciatic nerve is most commonly injured in this scenario, and what sensory deficit is expected?

. Tibial division; loss of sensation over the plantar foot
. Tibial division; loss of sensation over the medial malleolus
. Peroneal division; loss of sensation over the first dorsal web space
. Peroneal division; loss of sensation over the posterior calf
. Femoral nerve; loss of sensation over the anterior thigh

Correct Answer & Explanation

. Peroneal division; loss of sensation over the first dorsal web space

Explanation

The sciatic nerve is injured in 10-20% of posterior hip dislocations. The peroneal (fibular) division is far more susceptible to stretch injury due to its lateral position and secure tethering at the fibular neck, leading to foot drop and dorsal foot/first web space sensory loss.

Question 1623

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 the:

. External iliac and internal iliac systems via the obturator and inferior epigastric vessels
. Femoral artery and the internal pudendal artery
. Superior gluteal artery and the medial circumflex femoral artery
. Obturator artery and the pudendal nerve
. Deep circumflex iliac artery and the superior epigastric artery

Correct Answer & Explanation

. External iliac and internal iliac systems via the obturator and inferior epigastric vessels

Explanation

The 'corona mortis' (crown of death) is a highly variable vascular anastomosis between the external iliac system (usually via inferior epigastric vessels) and the internal iliac system (obturator vessels). It crosses the superior pubic ramus and is highly vulnerable during anterior pelvic surgical approaches.

Question 1624

Topic: Surgical Anatomy & Approaches

When performing a lateral approach to the distal humerus, understanding the course of the radial nerve is critical. On average, at what distance proximal to the lateral epicondyle does the radial nerve pierce the lateral intermuscular septum to enter the anterior compartment?

. 2-4 cm
. 5-7 cm
. 10-12 cm
. 14-16 cm
. 18-20 cm

Correct Answer & Explanation

. 10-12 cm

Explanation

The radial nerve courses from posterior to anterior by piercing the lateral intermuscular septum on average 10-12 cm proximal to the lateral epicondyle. Identifying this landmark is essential to safely dissect and protect the nerve during lateral or anterolateral approaches.

Question 1625

Topic: Surgical Anatomy & Approaches

During open reduction and internal fixation of a posterior glenoid rim fracture via a classic posterior approach, the surgeon dissects near the quadrangular space. Which vascular structure passes through this space alongside the axillary nerve?

. Anterior circumflex humeral artery
. Posterior circumflex humeral artery
. Profunda brachii artery
. Suprascapular artery
. Circumflex scapular artery

Correct Answer & Explanation

. Posterior circumflex humeral artery

Explanation

The posterior circumflex humeral artery travels with the axillary nerve through the quadrangular space. This space is bordered by the teres minor (superior), teres major (inferior), long head of the triceps (medial), and surgical neck of the humerus (lateral).

Question 1626

Topic: Surgical Anatomy & Approaches

An orthopedic surgeon is performing an ilioinguinal approach for an anterior column acetabular fracture. Severe hemorrhage occurs over the superior pubic ramus near the symphysis. This bleeding is most likely due to injury of the corona mortis, which represents an anastomosis between which two vascular systems?

. Internal iliac and pudendal
. External iliac (or inferior epigastric) and obturator
. Deep circumflex iliac and superior gluteal
. External iliac and internal pudendal
. Femoral and inferior epigastric

Correct Answer & Explanation

. External iliac (or inferior epigastric) and obturator

Explanation

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

Question 1627

Topic: Surgical Anatomy & Approaches

During an anterolateral approach to the distal humeral shaft, the surgeon longitudinally splits the brachialis muscle. What is the primary anatomic rationale for ensuring the lateral half of the brachialis remains intact against the bone?

. It preserves the musculocutaneous nerve innervation to the lateral half
. It acts as a soft tissue buffer to protect the radial nerve from the plate
. It protects the profunda brachii artery main trunk
. It preserves the radial nerve innervation to the medial half
. It provides a vascularized muscular bed from the brachial artery

Correct Answer & Explanation

. It acts as a soft tissue buffer to protect the radial nerve from the plate

Explanation

The radial nerve runs between the brachialis and the brachioradialis. Splitting the brachialis longitudinally allows the lateral portion of the muscle to serve as a protective soft-tissue cushion between the hardware and the radial nerve.

Question 1628

Topic: Surgical Anatomy & Approaches

A 24-year-old male suffers a posterior hip dislocation. Reduction is performed 8 hours post-injury. Which pathophysiological mechanism most directly contributes to the high risk of femoral head osteonecrosis in this specific clinical scenario?

. Disruption of the ligamentum teres artery
. Mechanical kinking of the external iliac artery
. Direct stretching or intimal tearing of the medial femoral circumflex artery
. Venous stasis secondary to iliofemoral ligament tension
. Thrombosis of the inferior gluteal artery

Correct Answer & Explanation

. Direct stretching or intimal tearing of the medial femoral circumflex artery

Explanation

Osteonecrosis following posterior hip dislocation is primarily driven by direct mechanical stretching, kinking, or intimal tearing of the deep branch of the medial femoral circumflex artery (MFCA) during the dislocation event.

Question 1629

Topic: Surgical Anatomy & Approaches

A 35-year-old male requires open reduction and internal fixation of a Pipkin Type II femoral head fracture. The surgeon elects to use an anterior (Smith-Petersen) approach. Which vascular structure consistently crosses the internervous plane of this approach and typically requires ligation?

. Ascending branch of the lateral circumflex femoral artery
. Deep branch of the medial circumflex femoral artery
. Inferior gluteal artery
. Transverse branch of the lateral circumflex femoral artery
. First perforating branch of the profunda femoris

Correct Answer & Explanation

. Ascending branch of the lateral circumflex femoral artery

Explanation

The Smith-Petersen (anterior) approach utilizes the internervous plane between the sartorius (femoral nerve) and tensor fascia lata (superior gluteal nerve). The ascending branch of the lateral circumflex femoral artery transversely crosses this plane and usually requires ligation to achieve adequate deep exposure without tearing.

Question 1630

Topic: Surgical Anatomy & Approaches

A 68-year-old female undergoes open reduction and internal fixation of a 3-part proximal humerus fracture via a deltopectoral approach. To safely mobilize the proximal fragment, the surgeon must be mindful of the axillary nerve. Which vascular structure courses with this nerve through the quadrangular space, and what are the boundaries of this space?

. Anterior circumflex humeral artery; bounded by the teres minor, teres major, long head of triceps, and humeral shaft.
. Posterior circumflex humeral artery; bounded by the teres minor, teres major, long head of triceps, and humeral shaft.
. Profunda brachii artery; bounded by the teres minor, teres major, long head of triceps, and humeral shaft.
. Posterior circumflex humeral artery; bounded by the teres minor, teres major, lateral head of triceps, and humeral shaft.
. Anterior circumflex humeral artery; bounded by the subscapularis, teres major, long head of triceps, and humeral shaft.

Correct Answer & Explanation

. Posterior circumflex humeral artery; bounded by the teres minor, teres major, long head of triceps, and humeral shaft.

Explanation

The axillary nerve and posterior circumflex humeral artery exit the axilla posteriorly through the quadrangular space. The boundaries are the teres minor (superior), teres major (inferior), long head of the triceps (medial), and the surgical neck of the humerus (lateral).

Question 1631

Topic: Surgical Anatomy & Approaches

A patient presents with a wrist drop following a humeral shaft fracture. Which nerve is most likely to be injured?

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

Correct Answer & Explanation

. Radial nerve

Explanation

A 'wrist drop' is the classic sign of radial nerve palsy, which commonly occurs with humeral shaft fractures due to the proximity of the radial nerve to the humeral shaft in the spiral groove. The radial nerve innervates the extensors of the wrist and fingers. Median nerve injury would affect wrist and finger flexion and thumb opposition. Ulnar nerve injury would affect intrinsic hand muscles and sensation to the small and ulnar half of the ring finger. Axillary nerve injury affects the deltoid, leading to shoulder abduction weakness. Musculocutaneous nerve injury affects biceps and brachialis.

Question 1632

Topic: Surgical Anatomy & Approaches

Which nerve is at highest risk of injury during surgical fixation of a proximal humerus fracture via a deltopectoral approach?

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

Correct Answer & Explanation

. Axillary nerve

Explanation

The axillary nerve (C5-C6) is at highest risk of injury during surgical approaches to the proximal humerus, especially the deltopectoral approach. It courses around the surgical neck of the humerus, approximately 5-7 cm distal to the acromion, making it vulnerable during plate application, screw insertion, or excessive retraction of the deltoid. Injury can lead to deltoid paralysis and sensory loss over the lateral shoulder. The radial nerve is at risk more distally in the humerus (spiral groove). The musculocutaneous, median, and ulnar nerves are generally protected by their more medial and anterior/posterior positions relative to the deltopectoral interval.

Question 1633

Topic: Surgical Anatomy & Approaches

Which nerve is most at risk of injury during surgical exposure of the anterior column of the acetabulum through an ilioinguinal approach?

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

Correct Answer & Explanation

. Femoral nerve.

Explanation

During an ilioinguinal approach for anterior column acetabular fractures, the femoral nerve is most at risk of injury. It lies within the middle window of the ilioinguinal approach, deep to the iliopsoas muscle and lateral to the femoral artery. The sciatic nerve is posterior. The obturator nerve is more medial within the pelvis. The lateral femoral cutaneous nerve is also at risk, but femoral nerve injury can be more devastating. The superior gluteal nerve is superior and lateral, typically associated with posterior approaches.

Question 1634

Topic: Surgical Anatomy & Approaches

Which of the following is a potential late complication of chronic pelvic trauma or pelvic surgery that can lead to persistent perineal or pelvic pain?

. Meralgia paresthetica.
. Piriformis syndrome.
. Pudendal neuralgia.
. Obturator nerve entrapment.
. Sciatica.

Correct Answer & Explanation

. Pudendal neuralgia.

Explanation

Pudendal neuralgia is characterized by chronic neuropathic pain in the perineum, external genitalia, or anorectal region, often exacerbated by sitting. It can result from direct trauma, nerve compression (e.g., from scar tissue or hematoma after pelvic trauma or surgery), or entrapment in Alcock's canal. While the other listed conditions are types of nerve entrapment or pain syndromes, pudendal neuralgia specifically correlates with perineal/pelvic pain and is a known, albeit uncommon, late complication of pelvic trauma or surgery. Meralgia paresthetica involves the lateral femoral cutaneous nerve (thigh), piriformis syndrome involves the sciatic nerve (buttock/leg), obturator nerve entrapment causes groin/medial thigh pain, and sciatica is general sciatic nerve pain.

Question 1635

Topic: Surgical Anatomy & Approaches

Which surgical approach for a lumbar discectomy carries the highest risk of iatrogenic injury to the ureter?

. Posterior midline microdiscectomy.
. Transforaminal lumbar interbody fusion (TLIF).
. Posterolateral fusion.
. Direct anterior lumbar interbody fusion (ALIF).
. Oblique lumbar interbody fusion (OLIF).

Correct Answer & Explanation

. Direct anterior lumbar interbody fusion (ALIF).

Explanation

The direct anterior lumbar interbody fusion (ALIF) approach requires significant retroperitoneal dissection and mobilization of the great vessels. The ureters lie within the retroperitoneum and are at risk of injury (laceration, clamping, kinking) during this extensive exposure. While OLIF also involves a retroperitoneal approach, it is generally considered less invasive than a direct ALIF and potentially carries a lower risk for ureteral injury if carefully performed. Posterior, transforaminal, and posterolateral approaches are far removed from the ureters and thus carry negligible risk of ureteral injury.

Question 1636

Topic: Surgical Anatomy & Approaches

Which nerve is most commonly injured with a midshaft humerus fracture?

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

Correct Answer & Explanation

. Radial nerve

Explanation

The radial nerve courses in the spiral groove along the posterior aspect of the humerus shaft, making it highly susceptible to injury during midshaft humerus fractures. Injury can result in wrist drop and sensory deficits on the dorsum of the hand. The median and ulnar nerves are more medially located, and the axillary nerve is more proximal.

Question 1637

Topic: Surgical Anatomy & Approaches

A 50-year-old female presents with progressive weakness and muscle atrophy in the deltoid and biceps after a motor vehicle accident that caused a clavicle fracture. Examination reveals diminished sensation over the lateral aspect of the shoulder. Which nerve root or peripheral nerve is most likely involved?

. C5 nerve root.
. C6 nerve root.
. C7 nerve root.
. Axillary nerve.
. Musculocutaneous nerve.

Correct Answer & Explanation

. C5 nerve root.

Explanation

Weakness of the deltoid and biceps, along with sensory loss over the lateral aspect of the shoulder, points to involvement of the C5 nerve root. The deltoid is primarily innervated by the axillary nerve (C5-C6), and the biceps by the musculocutaneous nerve (C5-C7). Both of these nerves derive significant input from C5. A clavicle fracture can cause brachial plexus injury, and C5 is a common component involved. The axillary nerve is a peripheral nerve, but the question asks about nerve root or peripheral nerve and C5 is the root level providing the most prominent motor and sensory deficits described.

Question 1638

Topic: Surgical Anatomy & Approaches

A 35-year-old male presents with sudden onset excruciating left hip pain after a high-energy motor vehicle collision. He is found with his left hip flexed, adducted, and internally rotated. Pulses are palpable distally. Which of the following is the most critical immediate management step?

. Order an MRI of the hip.
. Administer strong analgesics and arrange for emergent closed reduction.
. Prepare for open reduction and internal fixation.
. Perform an arthrocentesis of the hip joint.
. Immobilize the hip in the deformed position and await elective surgery.

Correct Answer & Explanation

. Administer strong analgesics and arrange for emergent closed reduction.

Explanation

The patient's presentation is classic for a posterior hip dislocation. This is an orthopedic emergency due to the high risk of avascular necrosis (AVN) of the femoral head and sciatic nerve injury. The most critical immediate step after assessing neurovascular status and administering analgesia is emergent closed reduction, ideally within 6 hours, to minimize the risk of AVN. Delay can significantly increase the risk of complications. MRI is useful after reduction to assess for occult fractures or soft tissue injuries, but not before emergent reduction. Open reduction is considered if closed reduction fails. Arthrocentesis is not indicated. Immobilizing in the deformed position will exacerbate complications.

Question 1639

Topic: Surgical Anatomy & Approaches

A 62-year-old female presents with a small, firm, tender lump at the site of a prior laparoscopic ventral hernia repair. She has no vomiting, distention, or obstipation but reports increasing localized pain. The surgeon suspects a Richter hernia. What is the most appropriate initial surgical approach?

. Observation with pain control and bowel rest.
. Attempt manual reduction under conscious sedation.
. Urgent surgical exploration and repair.
. Prescribe broad-spectrum antibiotics and re-evaluate in 24 hours.
. Order a barium follow-through study to assess bowel patency.

Correct Answer & Explanation

. Urgent surgical exploration and repair.

Explanation

Urgent surgical exploration and repair is the most appropriate initial surgical approach for a suspected Richter hernia, especially when it is tender and firm. Richter hernias have a high risk of strangulation and perforation due to the tight constriction of the partially incarcerated bowel. Delay can lead to irreversible bowel damage, peritonitis, and sepsis. Observation, manual reduction attempts (especially if there are signs of ischemia), antibiotics alone, or diagnostic studies that delay definitive treatment are inappropriate for a suspected surgical emergency.

Question 1640

Topic: Surgical Anatomy & Approaches

A patient with a traumatic posterior shoulder dislocation presents. What nerve injury is most commonly associated with this injury?

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

Correct Answer & Explanation

. Axillary nerve

Explanation

The axillary nerve (C5, C6) is the most commonly injured nerve in association with shoulder dislocations, both anterior and posterior. It innervates the deltoid and teres minor muscles and provides sensation over the 'regimental badge' area. The radial, median, ulnar, and musculocutaneous nerves are less frequently involved in isolated shoulder dislocations.

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