Menu

Surgical Anatomy & Approaches MCQs

Practice Set 6 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 101

Topic: Surgical Anatomy & Approaches

Regarding the posterior interosseous nerve (PIN) during surgical approaches to the radial head, at what point is it most vulnerable?

. As it passes anterior to the humerus
. As it exits the radial tunnel
. As it pierces the superficial head of the supinator muscle
. Distal to the radial tuberosity
. Proximally, near the axilla

Correct Answer & Explanation

. As it pierces the superficial head of the supinator muscle

Explanation

Correct Answer: CThe posterior interosseous nerve (PIN) is a branch of the radial nerve. It becomes vulnerable as it enters and passes through the supinator muscle (often referred to as the Arcade of Frohse, the proximal edge of the superficial head of the supinator). During surgical approaches to the radial head, particularly if the dissection extends too far anterior or distal, the PIN can be at risk, especially where it pierces the superficial head of the supinator muscle within the radial tunnel. This is why the Kocher approach, staying posterior, is preferred.

Question 102

Topic: Surgical Anatomy & Approaches

A 40-year-old male sustains a posterior wall acetabular fracture with an associated posterior hip dislocation. Which neurologic deficit is most likely to be observed on physical examination?

. Inability to extend the knee (femoral nerve)
. Inability to adduct the hip (obturator nerve)
. Inability to actively plantarflex the ankle (tibial division of the sciatic nerve)
. Inability to actively dorsiflex the ankle (peroneal division of the sciatic nerve)
. Numbness over the medial aspect of the calf (saphenous nerve)

Correct Answer & Explanation

. Inability to actively dorsiflex the ankle (peroneal division of the sciatic nerve)

Explanation

Posterior hip dislocations and posterior wall acetabular fractures most commonly injure the sciatic nerve. The peroneal division is more lateral, tightly tethered, and has larger fascicles with less connective tissue, making it much more susceptible to injury than the tibial division.

Question 103

Topic: Surgical Anatomy & Approaches

A 35-year-old male presents after a fall with a posterior hip dislocation. After successful closed reduction, he complains of weakness in ankle dorsiflexion and eversion, along with numbness over the dorsum of his foot. Which nerve is most likely injured?

. Femoral nerve
. Obturator nerve
. Sciatic nerve (common peroneal division)
. Superior gluteal nerve
. Inferior gluteal nerve

Correct Answer & Explanation

. Sciatic nerve (common peroneal division)

Explanation

Correct Answer: CPosterior hip dislocations are frequently associated with sciatic nerve injuries, particularly the common peroneal (fibular) division. This division supplies the muscles responsible for ankle dorsiflexion (e.g., tibialis anterior) and eversion (e.g., peroneus longus and brevis) and provides sensation to the dorsum of the foot. The tibial division of the sciatic nerve primarily supplies plantarflexors and foot intrinsics, and sensation to the sole. Femoral and obturator nerves are typically spared in posterior dislocations. Gluteal nerves supply gluteal muscles.

Question 104

Topic: Surgical Anatomy & Approaches

A 60-year-old male undergoes an anterior lumbar interbody fusion (ALIF) at L4-L5. Postoperatively, he develops abdominal distension, absent bowel sounds, and is unable to void, requiring Foley catheterization. Which of the following is the most likely cause of his urinary retention and paralytic ileus?

. Damage to the femoral nerve during surgical approach.
. Spinal cord injury during instrumentation.
. Retrograde ejaculation due to superior hypogastric plexus injury.
. Temporary autonomic dysfunction due to surgical manipulation of the retroperitoneal structures and sympathetic plexus.
. Urinary tract infection (UTI) causing ileus.

Correct Answer & Explanation

. Temporary autonomic dysfunction due to surgical manipulation of the retroperitoneal structures and sympathetic plexus.

Explanation

Correct Answer: DAnterior lumbar interbody fusion (ALIF) involves a retroperitoneal approach, requiring mobilization of great vessels and manipulation of the anterior longitudinal ligament. This manipulation can temporarily injure or irritate the sympathetic nerve fibers and the superior hypogastric plexus, leading to transient autonomic dysfunction manifesting as paralytic ileus and urinary retention. While retrograde ejaculation is a known, more specific, and often permanent complication of superior hypogastric plexus injury during ALIF in males, generalized transient autonomic dysfunction encompassing both ileus and urinary retention is a more common immediate postoperative issue. Femoral nerve injury is less common with a proper ALIF approach. Spinal cord injury is very unlikely at the lumbar level in an ALIF. A UTI can cause urinary retention, but not typically directly cause paralytic ileus concurrently as an immediate post-op complication of this type of surgery.

Question 105

Topic: Surgical Anatomy & Approaches

A 70-year-old male undergoes a total hip arthroplasty for severe osteoarthritis. Postoperatively, he develops a foot drop and diminished sensation over the dorsum of the foot and lateral leg. Which nerve injury is most likely responsible?

. Femoral nerve
. Obturator nerve
. Sciatic nerve (common peroneal division)
. Sciatic nerve (tibial division)
. Superior gluteal nerve

Correct Answer & Explanation

. Sciatic nerve (common peroneal division)

Explanation

Correct Answer: CFoot drop and diminished sensation over the dorsum of the foot and lateral leg are classic signs of common peroneal nerve palsy. The common peroneal nerve is a division of the sciatic nerve and is particularly vulnerable during total hip arthroplasty due to traction, direct trauma, or compression, especially in cases of leg lengthening or revision surgery. Femoral nerve injury affects quadriceps strength, obturator nerve injury affects adduction, and tibial nerve injury affects plantarflexion and sensation over the sole of the foot. Superior gluteal nerve injury would affect abductor function.

Question 106

Topic: Surgical Anatomy & Approaches

A 28-year-old male sustains a posterior hip dislocation after a dashboard injury in an MVC. On examination, his hip is internally rotated, adducted, and flexed. He has diminished sensation in the plantar aspect of his foot and weakness in ankle dorsiflexion and eversion. What is the most appropriate initial management step, considering the neurovascular status?

. Obtain an immediate CT scan of the hip to rule out associated fractures.
. Attempt closed reduction under conscious sedation as soon as possible.
. Perform an emergent open reduction due to neurological deficit.
. Order an MRI to assess for labral tears and capsular integrity.
. Place the patient in skeletal traction until swelling subsides.

Correct Answer & Explanation

. Attempt closed reduction under conscious sedation as soon as possible.

Explanation

Correct Answer: BPosterior hip dislocations are orthopedic emergencies due to the high risk of avascular necrosis (AVN) of the femoral head and associated sciatic nerve injury. The most critical factor is the time to reduction. A neurological deficit (like the described sciatic nerve palsy) does NOT contraindicate immediate closed reduction. In fact, prompt reduction may allow for neurological recovery. A CT scan is important AFTER successful closed reduction to assess for incarcerated fragments or occult fractures (e.g., femoral head impaction, posterior wall acetabular fracture), but it should not delay reduction. Open reduction is reserved for failed closed reduction or irreducible dislocations. MRI is not an acute management tool.

Question 107

Topic: Surgical Anatomy & Approaches

A 25-year-old unrestrained driver suffers a posterior hip dislocation in a motor vehicle collision. Following closed reduction, the patient exhibits a foot drop and inability to extend the toes. Which nerve division is most likely injured?

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

Correct Answer & Explanation

. Peroneal division of the sciatic nerve

Explanation

The common peroneal division of the sciatic nerve is most susceptible to injury during a posterior hip dislocation. This is due to its lateral position and secure tethering at the sciatic notch and fibular neck.

Question 108

Topic: Surgical Anatomy & Approaches

A 14-year-old female with a high-grade osteosarcoma of the proximal humerus has completed neoadjuvant chemotherapy. Post-chemotherapy MRI shows a good response with significant tumor shrinkage. The surgical plan is for limb salvage. Which of the following nerves is at highest risk of injury during the surgical approach to the proximal humerus, particularly when dissecting around the surgical neck and deltoid?

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

Correct Answer & Explanation

. Axillary nerve

Explanation

Correct Answer: DExplanation:Theaxillary nerveis the nerve at highest risk of injury during surgical approaches to the proximal humerus, especially when the dissection involves the surgical neck and the deltoid muscle. The axillary nerve originates from the posterior cord of the brachial plexus (C5, C6), passes posteriorly around the surgical neck of the humerus, and innervates the deltoid and teres minor muscles. Damage to this nerve results in paralysis of the deltoid, leading to significant impairment of shoulder abduction and external rotation, and sensory loss over the lateral shoulder.A. Radial nerve:The radial nerve also originates from the posterior cord and spirals around the posterior aspect of the humerus in the radial groove, making it vulnerable in mid-shaft humeral fractures or approaches to the posterior humerus, but less so in the immediate proximal humeral surgical neck region compared to the axillary nerve.B. Ulnar nerve:The ulnar nerve runs medially in the arm and is typically not at high risk during proximal humeral approaches unless dissection extends significantly medially or distally.C. Median nerve:The median nerve runs with the brachial artery in the anterior compartment of the arm and is generally not at high risk during standard proximal humeral approaches.E. Musculocutaneous nerve:This nerve innervates the anterior compartment muscles of the arm (biceps, brachialis) and is typically more anterior and distal to the immediate surgical neck area.

Question 109

Topic: Surgical Anatomy & Approaches

An orthopedic surgeon is performing a deltoid-splitting approach for an open rotator cuff repair. To avoid denervating the anterior deltoid, the split must not extend too far distally. What is the approximate safe distance from the lateral edge of the acromion before risking injury to the axillary nerve?

. 1 cm
. 3 cm
. 5 cm
. 8 cm
. 10 cm

Correct Answer & Explanation

. 5 cm

Explanation

The axillary nerve runs transversely across the deep surface of the deltoid muscle, approximately 5 cm distal to the lateral edge of the acromion. Extending a deltoid split beyond this distance places the nerve at high risk of iatrogenic injury.

Question 110

Topic: Surgical Anatomy & Approaches

A 28-year-old male volleyball player presents with insidious onset of posterior shoulder pain and isolated weakness in external rotation. An MRI reveals a paralabral cyst. Where is this cyst most likely located, and what nerve is compressed?

. Suprascapular notch, compressing the suprascapular nerve
. Spinoglenoid notch, compressing the suprascapular nerve
. Quadrilateral space, compressing the axillary nerve
. Triangular interval, compressing the radial nerve
. Spinoglenoid notch, compressing the dorsal scapular nerve

Correct Answer & Explanation

. Spinoglenoid notch, compressing the suprascapular nerve

Explanation

A paralabral cyst in the spinoglenoid notch compresses the distal branch of the suprascapular nerve, causing isolated denervation and weakness of the infraspinatus. Compression at the suprascapular notch would affect both the supraspinatus and infraspinatus.

Question 111

Topic: Surgical Anatomy & Approaches

During your explanation of a complex surgical approach, the examiner repeatedly interrupts with challenging follow-up questions. What is the MOST effective strategy to maintain composure and demonstrate mastery?

. Becoming visibly flustered, losing your train of thought, and showing frustration.
. Ignoring the interruptions and attempting to complete your original explanation regardless.
. Pausing briefly, acknowledging the interruption, concisely answering the specific follow-up question, and then subtly and smoothly returning to your original structured answer.
. Asking the examiner politely but firmly to hold their questions until you have finished your monologue.
. Shifting focus entirely to the examiner's line of questioning, abandoning your planned structure and depth.

Correct Answer & Explanation

. Pausing briefly, acknowledging the interruption, concisely answering the specific follow-up question, and then subtly and smoothly returning to your original structured answer.

Explanation

Correct Answer: CExaminers often use interruptions to test a candidate's ability to think on their feet, manage pressure, and maintain a structured thought process. The most effective strategy is to acknowledge the interruption, address the specific question concisely, and then gracefully pivot back to your original, planned answer structure. This demonstrates flexibility, responsiveness, and an ability to stay organized under pressure. Ignoring or directly challenging the examiner is unprofessional and detrimental to the candidate's perceived professionalism and ability to handle pressure.

Question 112

Topic: Surgical Anatomy & Approaches

When addressing a terrible triad injury surgically, what is the primary advantage of utilizing the Kaplan approach (extensor digitorum communis splitting) over the Kocher approach (ECU and anconeus interval)?

. Improved access to the medial collateral ligament
. Decreased risk to the posterior interosseous nerve
. Better visualization of the anteromedial coronoid facet
. Direct access to the sublime tubercle
. Enhanced exposure of the proximal radioulnar joint avoiding LCL detachment

Correct Answer & Explanation

. Better visualization of the anteromedial coronoid facet

Explanation

The Kaplan approach is located more anteriorly than the Kocher approach, providing better direct visualization of the anteromedial coronoid for fixation. However, it carries a higher theoretical risk to the PIN if dissection is extended too far distally.

Question 113

Topic: Surgical Anatomy & Approaches

When utilizing the standard volar approach (modified Henry) for open reduction and internal fixation of a distal radius fracture, the surgeon initially develops an interval between which two structures to safely access the deeper pronator quadratus?

. Flexor carpi radialis (FCR) tendon and the radial artery
. Flexor carpi radialis (FCR) and palmaris longus (PL) tendons
. Brachioradialis and the radial artery
. Flexor pollicis longus (FPL) and flexor digitorum superficialis (FDS)
. Abductor pollicis longus (APL) and extensor pollicis brevis (EPB)

Correct Answer & Explanation

. Flexor carpi radialis (FCR) tendon and the radial artery

Explanation

The modified Henry approach utilizes the internervous plane between the median nerve (supplying FCR) and the radial nerve (supplying brachioradialis). Superficially, the surgeon develops the interval between the FCR tendon and the radial artery to safely retract the neurovascular structures.

Question 114

Topic: Surgical Anatomy & Approaches

During a surgical approach to the proximal ulna for a diaphyseal fracture, a surgeon utilizes the posterior (dorsal) subcutaneous approach. Which of the following structures is the most significant concern for iatrogenic injury with this specific approach?

. Ulnar nerve.
. Posterior interosseous nerve.
. Radial artery.
. Superficial radial nerve.
. No major neurovascular structures are at significant risk with this approach.

Correct Answer & Explanation

. No major neurovascular structures are at significant risk with this approach.

Explanation

Correct Answer: EThe posterior (dorsal) subcutaneous approach to the ulna shaft is generally considered the safest and most direct because the ulna is largely subcutaneous along its posterior border. This approach requires minimal muscle dissection, thereby significantly reducing the risk of injury to major neurovascular structures. The ulnar nerve, radial artery, and radial nerve branches are located more anteriorly or laterally in the forearm, away from the direct path of this approach to the ulna.Incorrect Options:A. Ulnar nerve:The ulnar nerve is located medially and volarly in the forearm, not typically at risk with a direct posterior approach to the ulna shaft.B. Posterior interosseous nerve:The posterior interosseous nerve (PIN) is a branch of the radial nerve and is located in the dorsal compartment of the forearm, but it is typically deep and lateral, not directly in the field of a posterior subcutaneous ulnar approach. It is more at risk with dorsal approaches to the radius.C. Radial artery:The radial artery is located on the volar-radial aspect of the forearm and is at risk with the Henry (anterior) approach to the radius, not the posterior ulna.D. Superficial radial nerve:The superficial radial nerve is also on the radial side of the forearm, deep to the brachioradialis, and is at risk with radial approaches, not the posterior ulna.

Question 115

Topic: Surgical Anatomy & Approaches

When utilizing the dorsal (Thompson) approach to expose the proximal radius, the surgeon develops the internervous plane between which of the following muscle groups?

. Brachioradialis and Pronator Teres
. Extensor Carpi Radialis Brevis and Extensor Digitorum Communis
. Flexor Carpi Radialis and Palmaris Longus
. Extensor Carpi Ulnaris and Flexor Carpi Ulnaris
. Extensor Carpi Radialis Longus and Extensor Carpi Radialis Brevis

Correct Answer & Explanation

. Extensor Carpi Radialis Brevis and Extensor Digitorum Communis

Explanation

The Thompson approach accesses the radius dorsally through the internervous plane between the extensor carpi radialis brevis (supplied by the radial nerve) and the extensor digitorum communis (supplied by the posterior interosseous nerve).

Question 116

Topic: Surgical Anatomy & Approaches

When performing a volar (Henry) approach to the mid-shaft radius, the surgeon develops the internervous plane between the brachioradialis and the flexor carpi radialis. Which nerves supply these respective muscles?

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

Correct Answer & Explanation

. Radial and Median

Explanation

The distal portion of the Henry approach utilizes the internervous plane between the brachioradialis, which is innervated by the radial nerve, and the flexor carpi radialis, which is innervated by the median nerve.

Question 117

Topic: Surgical Anatomy & Approaches

During the distal extension of the Henry approach to the radius, the surgeon must carefully mobilize and retract a specific artery to safely expose the underlying pronator quadratus. Which artery is this, and in which direction is it retracted?

. Ulnar artery, retracted ulnarly
. Radial artery, retracted radially
. Ulnar artery, retracted radially
. Anterior interosseous artery, retracted radially
. Radial artery, retracted ulnarly

Correct Answer & Explanation

. Radial artery, retracted radially

Explanation

In the distal Henry approach, the radial artery lies medial to the brachioradialis. It must be carefully mobilized and retracted radially, along with the brachioradialis tendon, to expose the pronator quadratus and distal radius.

Question 118

Topic: Surgical Anatomy & Approaches

A surgeon elects to use the dorsal Thompson approach for open reduction and internal fixation of a proximal third radial shaft fracture. This approach utilizes an internervous plane between which two muscles?

. Extensor carpi radialis brevis and Extensor digitorum communis
. Brachioradialis and Pronator teres
. Extensor carpi ulnaris and Flexor carpi ulnaris
. Extensor digitorum communis and Extensor carpi ulnaris
. Flexor carpi radialis and Palmaris longus

Correct Answer & Explanation

. Extensor carpi radialis brevis and Extensor digitorum communis

Explanation

The Thompson approach utilizes the internervous plane between the extensor carpi radialis brevis (radial nerve) and the extensor digitorum communis (posterior interosseous nerve).

Question 119

Topic: Surgical Anatomy & Approaches

When extending the volar (Henry) approach proximally to address a fracture of the proximal third of the radius, the surgeon must carefully identify and protect a key neural structure. To do so safely, which maneuver is most appropriate?

. Identify the median nerve between the two heads of the pronator teres.
. Supinate the forearm to rotate the posterior interosseous nerve (PIN) laterally away from the surgical field.
. Pronate the forearm to move the posterior interosseous nerve (PIN) medially.
. Release the brachioradialis insertion completely to visualize the superficial radial nerve.
. Elevate the flexor digitorum profundus off the ulna to protect the anterior interosseous nerve.

Correct Answer & Explanation

. Supinate the forearm to rotate the posterior interosseous nerve (PIN) laterally away from the surgical field.

Explanation

When exposing the proximal radius via the Henry approach, the forearm must be supinated. This rotates the radius and moves the supinator muscle and the enclosed posterior interosseous nerve (PIN) laterally, protecting it from injury.

Question 120

Topic: Surgical Anatomy & Approaches

During an anterior (Henry) approach to the proximal radius, the surgeon develops the internervous plane. Between which two muscles is the proximal portion of this plane located?

. Brachioradialis and flexor carpi radialis
. Brachioradialis and pronator teres
. Flexor carpi ulnaris and flexor digitorum superficialis
. Extensor carpi radialis brevis and extensor digitorum communis
. Flexor carpi radialis and palmaris longus

Correct Answer & Explanation

. Brachioradialis and pronator teres

Explanation

The proximal internervous plane for the Henry approach lies between the brachioradialis (innervated by the radial nerve) and the pronator teres (innervated by the median nerve). Distally, the plane transitions between the brachioradialis and the flexor carpi radialis.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page