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Surgical Anatomy & Approaches MCQs

Practice Set 97 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 1921

Topic: Surgical Anatomy & Approaches
A 60-year-old woman undergoes a ligament reconstruction and tendon interposition (LRTI) procedure for Eaton-Littler Stage III thumb carpometacarpal (CMC) arthritis via a dorsal approach. Which nerve is most at risk of injury during the surgical dissection down to the CMC joint capsule?
. Palmar cutaneous branch of the median nerve
. Deep motor branch of the ulnar nerve
. Superficial branch of the radial nerve
. Lateral antebrachial cutaneous nerve
. Posterior interosseous nerve

Correct Answer & Explanation

. Superficial branch of the radial nerve

Explanation

The dorsal surgical approach to the thumb CMC joint typically exploits the interval between the first extensor compartment (APL, EPB) and the third extensor compartment (EPL). The superficial branch of the radial nerve runs directly over this region to supply sensation to the dorsal-radial aspect of the hand and thumb, making it highly susceptible to iatrogenic injury or traction neuritis during CMC arthroplasty.

Question 1922

Topic: Surgical Anatomy & Approaches

During a volar Henry approach to fix a distal radius fracture, the surgeon develops the interval between the flexor carpi radialis (FCR) and the radial artery. Which muscle must be elevated from the radius to directly expose the volar fracture fragments?

. Pronator teres
. Flexor pollicis longus
. Pronator quadratus
. Brachioradialis
. Flexor digitorum superficialis

Correct Answer & Explanation

. Pronator quadratus

Explanation

The pronator quadratus natively covers the volar aspect of the distal radius. In the volar Henry approach, an L-shaped incision is made to release the pronator quadratus from its radial and distal borders, reflecting it ulnarly to expose the bone.

Question 1923

Topic: Surgical Anatomy & Approaches

What is the recommended approach for managing a PJI caused by multiple organisms (polymicrobial infection) versus a monomicrobial infection?

. Polymicrobial infections are generally easier to treat due to broader antibiotic susceptibility.
. Polymicrobial infections typically require a more aggressive surgical approach (e.g., two-stage revision) and broader antibiotic coverage.
. Monomicrobial infections always require implant removal, whereas polymicrobial can be treated with DAIR.
. The choice of antibiotics is simpler for polymicrobial infections.
. Polymicrobial infections carry a better prognosis than monomicrobial.

Correct Answer & Explanation

. Polymicrobial infections typically require a more aggressive surgical approach (e.g., two-stage revision) and broader antibiotic coverage.

Explanation

Polymicrobial infections are generally more challenging to treat than monomicrobial infections and are associated with a poorer prognosis. They often require a more aggressive surgical approach (typically two-stage revision) and broader, carefully selected antibiotic coverage to target all identified organisms. Their complexity makes them harder to eradicate. DAIR is less likely to succeed. Monomicrobial infections by virulent organisms can also necessitate implant removal. The choice of antibiotics is more complex, not simpler.

Question 1924

Topic: Surgical Anatomy & Approaches

A 40-year-old patient with chronic lateral ankle instability is found to have significant tendinosis and longitudinal tears of the peroneal brevis tendon on MRI. How might this influence the surgical management strategy for her instability?

. It suggests that a primary repair of the lateral ligaments will be sufficient.
. It necessitates the use of a Chrisman-Snook or Watson-Jones procedure for reconstruction.
. It complicates the repair and may require concomitant peroneal tendon debridement or repair.
. It indicates that the patient likely has a medial ankle instability instead.
. It means non-operative management is the only viable option.

Correct Answer & Explanation

. It complicates the repair and may require concomitant peroneal tendon debridement or repair.

Explanation

Concomitant peroneal tendon pathology (tendinosis, tears, or subluxation) is common in patients with chronic lateral ankle instability. If present, it must be addressed during the same surgical setting, typically through debridement, repair, or tenodesis of the peroneal tendons, in addition to the lateral ligament stabilization. Ignoring significant peroneal pathology can lead to continued pain, weakness, and potentially compromise the outcome of the instability repair. It does not necessarily preclude a primary ligament repair, but it adds another component to the surgical plan. Chrisman-Snook/Watson-Jones use healthy peroneal tendons, not torn ones.

Question 1925

Topic: Surgical Anatomy & Approaches

In a viva, you've explained your reasoning for using a particular surgical approach. The examiner challenges, 'But why would you choose that approach when XYZ approach has a demonstrably lower infection rate in some series?' What is the BEST way to respond to this challenge?

. Admit that you might be wrong and retract your initial choice.
. Defensively state that your chosen approach is what you were taught and are most comfortable with.
. Acknowledge the examiner's point about infection rates, then articulate specific patient-related factors, anatomical considerations, or biomechanical advantages that, inthis specific case, led you to favor your chosen approach, while briefly addressing how you mitigate the stated risk.
. Change the topic to another aspect of the case, avoiding the direct challenge.
. State that your institution's data shows no difference in infection rates, without further elaboration.

Correct Answer & Explanation

. Acknowledge the examiner's point about infection rates, then articulate specific patient-related factors, anatomical considerations, or biomechanical advantages that, inthis specific case, led you to favor your chosen approach, while briefly addressing how you mitigate the stated risk.

Explanation

When challenged, a confident and knowledgeable candidate acknowledges the validity of the examiner's point (if appropriate) but then provides a reasoned, case-specific justification for their decision. This demonstrates critical thinking, awareness of controversies, and the ability to apply evidence to individual patients. Avoiding defensiveness (B) or immediate retraction (A) is crucial. Changing the topic (D) is a significant viva error. Simply quoting institutional data (E) without explanation is insufficient.

Question 1926

Topic: Surgical Anatomy & Approaches

You are informed that your viva will heavily feature long cases. On the day before, which activity is most beneficial?

. Reviewing only short-answer facts for rapid recall.
. Practicing the systematic presentation of a patient history, examination, investigations, differential diagnosis, and management plan.
. Memorizing the entire pharmacology of osteoporotic drugs.
. Watching complex surgical videos without actively participating.
. Engaging in an intense debate about a controversial surgical approach.

Correct Answer & Explanation

. Practicing the systematic presentation of a patient history, examination, investigations, differential diagnosis, and management plan.

Explanation

Long cases require a structured approach to patient presentation and management. Practicing this systematic flow ensures all key elements are covered logically and efficiently, which is critical for scoring well in this format.

Question 1927

Topic: Surgical Anatomy & Approaches

When presented with an image of a complex periarticular fracture, what should be your FIRST step in verbalizing its interpretation?

. Immediately stating the specific classification system.
. Giving your opinion on the best surgical approach.
. Identify the patient demographics (if available), the anatomical location, type of imaging, and systematically describe the fracture characteristics (e.g., comminution, displacement, joint involvement, neurovascular status if implied) before classifying or discussing management.
. Asking the examiner what they want you to focus on.
. Comparing it to a similar case you've seen.

Correct Answer & Explanation

. Identify the patient demographics (if available), the anatomical location, type of imaging, and systematically describe the fracture characteristics (e.g., comminution, displacement, joint involvement, neurovascular status if implied) before classifying or discussing management.

Explanation

A systematic approach to imaging interpretation is paramount. Before classification or management, one must accurately and comprehensively describe what is seen. This includes basic patient/image information, precise anatomical localization, and detailed fracture characteristics. This structured description demonstrates thoroughness and ensures all critical elements are identified before moving to higher-level analysis like classification or treatment planning.

Question 1928

Topic: Surgical Anatomy & Approaches

Compression in the quadrilateral space typically leads to atrophy of the teres minor and deltoid. Which artery travels through this space alongside the affected nerve?

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

Correct Answer & Explanation

. Poster humeral circumflex artery

Explanation

The quadrilateral space contains the axillary nerve and the posterior humeral circumflex artery. It is bordered by the teres minor (superior), teres major (inferior), long head of the triceps (medial), and surgical neck of the humerus (lateral).

Question 1929

Topic: Surgical Anatomy & Approaches

During a total hip arthroplasty using the direct anterior approach (DAA), the surgeon exploits the internervous plane between the sartorius and the tensor fasciae latae (TFL). Which nerve provides the motor innervation to the muscle located immediately lateral to this interval?

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

Correct Answer & Explanation

. Superior gluteal nerve

Explanation

The direct anterior approach to the hip utilizes the internervous plane between the sartorius (medial) and the tensor fasciae latae (lateral). The sartorius is innervated by the femoral nerve. The tensor fasciae latae (TFL), located lateral to the interval, is innervated by the superior gluteal nerve. Understanding this plane prevents denervation of the key abductor musculature.

Question 1930

Topic: Surgical Anatomy & Approaches

A patient sustains a closed midshaft humerus fracture resulting in a radial nerve palsy. According to Seddon's classification of nerve injuries, a neurapraxia is characterized by which of the following?

. Complete axonal disruption with intact endoneurium
. Complete axonal disruption with disrupted endoneurium
. Focal demyelination with intact axons and no Wallerian degeneration
. Disruption of the epineurium, perineurium, and endoneurium
. Irreversible Wallerian degeneration distal to the injury

Correct Answer & Explanation

. Focal demyelination with intact axons and no Wallerian degeneration

Explanation

Neurapraxia (comparable to Sunderland Grade I) is a temporary physiological conduction block caused by focal demyelination. Because the axons themselves remain physically intact, Wallerian degeneration does not occur distal to the lesion. Recovery is usually spontaneous and complete within days to weeks. Axonal disruption defines axonotmesis, and complete nerve transection defines neurotmesis.

Question 1931

Topic: Surgical Anatomy & Approaches

A patient sustains a closed midshaft humerus fracture and presents with a dense radial nerve palsy. Electromyography at 4 weeks shows fibrillation potentials but no motor unit action potentials. If the nerve injury is classified as a Sunderland Grade II (axonotmesis), what key histological structure remains intact to allow for predictable axonal regeneration?

. Epineurium only
. Epineurium and perineurium only
. Endoneurium, perineurium, and epineurium
. Myelin sheath only
. Axolemma

Correct Answer & Explanation

. Endoneurium, perineurium, and epineurium

Explanation

In a Sunderland Grade II injury (axonotmesis), the axon is disrupted, leading to Wallerian degeneration distal to the injury site. However, the entire connective tissue framework (endoneurium, perineurium, and epineurium) remains completely intact, guiding the regenerating axon to its appropriate target at roughly 1 mm per day.

Question 1932

Topic: Surgical Anatomy & Approaches

During the anterior intrapelvic (modified Stoppa) approach for fixation of an acetabular fracture, the surgeon must identify and ligate the 'corona mortis' to prevent life-threatening hemorrhage. This structure is an anastomosis between which two vascular systems?

. Internal iliac and internal pudendal vessels
. Superior gluteal and internal iliac vessels
. Inferior gluteal and obturator vessels
. Internal pudendal and obturator vessels
. External iliac (or inferior epigastric) and obturator vessels

Correct Answer & Explanation

. External iliac (or inferior epigastric) and obturator vessels

Explanation

The corona mortis is a vascular anastomosis between the external iliac system (specifically the inferior epigastric vessels) and the obturator vessels. It crosses the superior pubic ramus and is highly susceptible to iatrogenic injury during anterior pelvic approaches.

Question 1933

Topic: Surgical Anatomy & Approaches

A patient sustains a closed midshaft humerus fracture and presents with a wrist drop. If the radial nerve injury is classified as an axonotmesis, which of the following components of the nerve remains intact?

. Axon only
. Axon and Myelin
. Endoneurium, perineurium, and epineurium
. Epineurium only
. No components remain intact

Correct Answer & Explanation

. Endoneurium, perineurium, and epineurium

Explanation

In axonotmesis (Sunderland second degree), the axon and myelin sheath are disrupted, causing Wallerian degeneration distal to the injury. However, the connective tissue framework (endoneurium, perineurium, and epineurium) remains completely intact, allowing for spontaneous axonal regeneration at approximately 1 mm/day.

Question 1934

Topic: Surgical Anatomy & Approaches

During the direct anterior approach (Smith-Petersen) to the hip, the superficial surgical interval exploits a true internervous plane between which two muscles?

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

Correct Answer & Explanation

. Sartorius and Tensor fasciae latae

Explanation

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

Question 1935

Topic: Surgical Anatomy & Approaches

A patient sustains a closed midshaft humerus fracture and presents with a radial nerve palsy. Three months later, EMG demonstrates fibrillation potentials but no motor unit action potentials (MUAPs). Based on Sunderland's classification, a 3rd-degree nerve injury involves disruption of which of the following structures?

. Myelin sheath only
. Axon only
. Axon and endoneurium
. Axon, endoneurium, and perineurium
. Entire nerve trunk including epineurium

Correct Answer & Explanation

. Axon only

Explanation

Sunderland classification: 1st degree (neuropraxia) = local myelin block; 2nd degree (axonotmesis) = axon severed, endoneurium intact; 3rd degree = axon and endoneurium severed, perineurium intact; 4th degree = axon, endoneurium, perineurium severed, epineurium intact; 5th degree (neurotmesis) = complete transection.

Question 1936

Topic: Surgical Anatomy & Approaches

A patient sustains a closed midshaft humerus fracture and presents with a secondary radial nerve palsy. An EMG at 4 weeks shows fibrillation potentials, but surgical exploration reveals an intact epineurium, perineurium, and endoneurium. According to the Seddon classification, this nerve injury is best classified as:

. Neuropraxia
. Axonotmesis
. Neurotmesis
. Sunderland Grade IV
. Sunderland Grade V

Correct Answer & Explanation

. Axonotmesis

Explanation

Axonotmesis involves disruption of the axon and myelin sheath with Wallerian degeneration (causing fibrillation potentials on EMG), but the supporting connective tissue frameworks (endoneurium, perineurium, epineurium) remain completely intact.

Question 1937

Topic: Surgical Anatomy & Approaches

A 35-year-old man with a chronic high radial nerve palsy undergoes functional tendon transfers. The surgeon transfers the pronator teres (PT) to the extensor carpi radialis brevis (ECRB) to restore wrist extension, and the flexor carpi ulnaris (FCU) to the extensor digitorum communis (EDC) to restore finger extension. Which of the following is the most appropriate transfer to restore thumb extension in this patient?

. Flexor carpi radialis to extensor digitorum communis
. Palmaris longus to extensor pollicis longus
. Pronator teres to extensor carpi radialis longus
. Flexor digitorum superficialis to extensor pollicis brevis
. Extensor indicis proprius to extensor pollicis longus

Correct Answer & Explanation

. Palmaris longus to extensor pollicis longus

Explanation

In a high radial nerve palsy, the palmaris longus (PL) to extensor pollicis longus (EPL) transfer is the gold standard for restoring thumb extension. The extensor indicis proprius (EIP) to EPL transfer is commonly used for spontaneous EPL ruptures, but it cannot be used in a radial nerve palsy because the EIP is innervated by the posterior interosseous nerve (PIN), which is nonfunctional in this scenario.

Question 1938

Topic: Surgical Anatomy & Approaches

During a direct anterior approach for a total hip arthroplasty, the surgeon develops the superficial internervous plane between the sartorius and the tensor fasciae latae (TFL). What are the respective motor innervations of these two muscles?

. Sartorius: Obturator nerve; TFL: Inferior gluteal nerve
. Sartorius: Femoral nerve; TFL: Inferior gluteal nerve
. Sartorius: Sciatic nerve; TFL: Superior gluteal nerve
. Sartorius: Femoral nerve; TFL: Femoral nerve
. Sartorius: Femoral nerve; TFL: Superior gluteal nerve

Correct Answer & Explanation

. Sartorius: Femoral nerve; TFL: Superior gluteal nerve

Explanation

The direct anterior approach (Smith-Petersen) to the hip utilizes a true internervous plane. Superficial to the fascia, the plane is between the sartorius (innervated by the femoral nerve) and the tensor fasciae latae (TFL, innervated by the superior gluteal nerve). Deep to the fascia, the plane is between the rectus femoris (femoral nerve) and gluteus medius (superior gluteal nerve).

Question 1939

Topic: Surgical Anatomy & Approaches

Following a closed humerus fracture, a patient develops a radial nerve palsy. According to the Sunderland classification of nerve injury, a Grade II injury (axonotmesis) is best defined by which of the following?

. Disruption of myelin with an intact axon
. Disruption of the axon with an intact endoneurium
. Disruption of the axon and endoneurium with an intact perineurium
. Disruption of the perineurium with an intact epineurium
. Complete physical transection of the nerve trunk

Correct Answer & Explanation

. Disruption of the axon with an intact endoneurium

Explanation

Sunderland Grade II (axonotmesis) involves disruption of the axon and myelin sheath, but the connective tissue framework (endoneurium, perineurium, epineurium) remains intact. This provides a clear tube for axonal regeneration, offering a good prognosis for recovery.

Question 1940

Topic: Surgical Anatomy & Approaches

During a direct lateral (deltoid-splitting) approach to the proximal humerus, the distal extent of the deltoid split must be carefully limited to no more than 5 cm distal to the acromion to prevent injury to which of the following structures?

. Musculocutaneous nerve
. Radial nerve
. Axillary nerve
. Suprascapular nerve
. Thoracodorsal nerve

Correct Answer & Explanation

. Axillary nerve

Explanation

The axillary nerve courses circumferentially around the proximal humerus deep to the deltoid muscle, typically 5 to 7 cm distal to the lateral edge of the acromion. Extending a deltoid split beyond this safe zone risks permanent denervation of the anterior deltoid.

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