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Surgical Anatomy & Approaches MCQs

Practice Set 78 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 1541

Topic: Surgical Anatomy & Approaches

A patient complains of leg pain. A positive Femoral Nerve Stretch Test (FNST) is performed, reproducing the patient's pain. This test is MOST sensitive for detecting compression of which nerve roots?

. L5 and S1
. S1 and S2
. L2 and L3
. L4 and L5
. C5 and C6

Correct Answer & Explanation

. L2 and L3

Explanation

The Femoral Nerve Stretch Test (FNST) involves extending the hip and flexing the knee with the patient prone, stretching the femoral nerve. This test is most sensitive for detecting compression of the L2, L3, and sometimes L4 nerve roots (femoral nerve distribution), typically associated with high lumbar disc herniations.

Question 1542

Topic: Surgical Anatomy & Approaches

During a straight leg raise (SLR) test, radicular pain is reproduced at 40 degrees of hip flexion. If dorsiflexion of the ankle then exacerbates the pain, what is this maneuver indicative of?

. Hamstring tightness
. Hip joint pathology
. Increased neural tension of the sciatic nerve
. Lumbar facet joint syndrome
. Piriformis muscle spasm

Correct Answer & Explanation

. Increased neural tension of the sciatic nerve

Explanation

Reproduction of radicular pain during an SLR test, especially when exacerbated by ankle dorsiflexion (Bragard's sign), is a strong indicator of increased neural tension or compression of the sciatic nerve roots (L4, L5, S1, S2). This maneuver further stretches the nerve, intensifying symptoms in the presence of irritation or compression. Hamstring tightness would cause posterior thigh pain but not typically radicular pain exacerbated by dorsiflexion.

Question 1543

Topic: Surgical Anatomy & Approaches

A patient presents with a severe post-traumatic valgus ankle with a depressed lateral tibial plafond. Mechanical axis planning demonstrates the CORA is located directly at the articular surface. Which surgical approach is necessitated by this specific CORA location to normalize the mechanical axis and restore joint congruity?

. A standard supramalleolar closing wedge osteotomy (SMO)
. A supramalleolar opening wedge osteotomy with translation
. An intra-articular osteotomy elevating the depressed segment
. A distal fibular lengthening without tibial intervention
. A focal dome osteotomy 3 cm proximal to the joint line

Correct Answer & Explanation

. An intra-articular osteotomy elevating the depressed segment

Explanation

When the CORA is located at the joint line due to a depressed articular segment, extra-articular osteotomies cannot restore joint congruity. An intra-articular osteotomy is required to elevate the fragment and simultaneously correct the mechanical axis.

Question 1544

Topic: Surgical Anatomy & Approaches

During the posterolateral approach to the distal humerus (e.g., Kocher approach), what is the interval primarily utilized?

. Between the brachialis and brachioradialis muscles
. Between the triceps and brachialis muscles
. Between the anconeus and extensor carpi ulnaris (ECU) muscles
. Between the flexor carpi ulnaris and flexor digitorum superficialis
. Between the brachioradialis and extensor carpi radialis longus

Correct Answer & Explanation

. Between the anconeus and extensor carpi ulnaris (ECU) muscles

Explanation

The posterolateral approach to the elbow, often referred to as the Kocher approach, utilizes the interval between the anconeus muscle and the extensor carpi ulnaris (ECU) muscle. This approach provides access to the lateral aspect of the elbow joint and distal humerus, particularly the capitellum, while protecting the radial nerve (which is more anterior and can be identified and protected with care). The other intervals are typically used for different approaches or expose different anatomical regions.

Question 1545

Topic: Surgical Anatomy & Approaches

Which muscle group is typically spared in a posterior interosseous nerve (PIN) palsy?

. Wrist extensors (e.g., extensor carpi radialis brevis)
. Finger extensors (e.g., extensor digitorum communis)
. Supinator
. Anconeus
. Extensor carpi radialis longus (ECRL)

Correct Answer & Explanation

. Extensor carpi radialis longus (ECRL)

Explanation

The extensor carpi radialis longus (ECRL) is typically spared in a posterior interosseous nerve (PIN) palsy because it is innervated by the radial nerve proximal to the division into superficial radial nerve and PIN. Therefore, patients with PIN palsy can still extend their wrist radially (ECRL action) but will have weakness or paralysis of finger and thumb extension, as well as ulnar wrist extension (ECU) and often weak supination (supinator). The anconeus is also innervated proximally to the PIN split.

Question 1546

Topic: Surgical Anatomy & Approaches

Which of the following describes the anatomical relationship of the FDP tendon relative to the FDS tendon in the finger?

. The FDP tendon lies superficial (more volar) to the FDS tendon.
. The FDP tendon lies deep (more dorsal) to the FDS tendon.
. The FDP and FDS tendons lie side-by-side in the flexor sheath.
. The FDP tendon passes through the split (decussation) of the FDS tendon at the DIP joint.
. The FDP tendon passes through the split (decussation) of the FDS tendon at the PIP joint.

Correct Answer & Explanation

. The FDP tendon passes through the split (decussation) of the FDS tendon at the PIP joint.

Explanation

In the finger, the FDP tendon lies deep (dorsal) to the FDS tendon until the level of the PIP joint. At the PIP joint, the FDS tendon splits (decussates) into two slips, allowing the FDP tendon to pass through this split to insert onto the distal phalanx. This anatomical relationship is critical for understanding flexor tendon mechanics and surgical approaches.

Question 1547

Topic: Surgical Anatomy & Approaches

Which of the following correctly describes the anatomical relationship of the neurovascular bundles in the fingers relative to the flexor tendons?

. The neurovascular bundles lie volar to the flexor tendons.
. The neurovascular bundles lie dorsal to the flexor tendons.
. The neurovascular bundles lie immediately radial and ulnar to the flexor tendons.
. The neurovascular bundles intertwine within the substance of the flexor tendons.
. The neurovascular bundles are located only on the dorsal aspect of the fingers.

Correct Answer & Explanation

. The neurovascular bundles lie immediately radial and ulnar to the flexor tendons.

Explanation

The digital neurovascular bundles (composed of the digital artery, nerve, and vein) run on the radial and ulnar sides of the flexor tendon sheath and phalanges within the finger. They are located just volar to the sagittal mid-axial line, making them vulnerable during surgical approaches or direct trauma. They do not lie volar or dorsal to the tendons in a consistent manner relative to the entire finger, nor do they intertwine with the tendons. They are not only dorsal.

Question 1548

Topic: Surgical Anatomy & Approaches

What is the standard surgical approach for open reduction internal fixation of an olecranon fracture?

. Anteromedial approach
. Lateral Kocher approach
. Posterior approach
. Anterior approach
. Medial approach

Correct Answer & Explanation

. Posterior approach

Explanation

The standard surgical approach for olecranon fractures is a posterior approach (C). This allows direct access to the olecranon, triceps tendon, and articular surface while carefully protecting the ulnar nerve, which is usually identified and mobilized medially.

Question 1549

Topic: Surgical Anatomy & Approaches

Regarding plate placement for diaphyseal forearm fractures, which statement is most accurate?

. The radius is ideally plated on its dorsal surface, and the ulna on its volar surface.
. Both radius and ulna are ideally plated on their dorsal surfaces.
. Both radius and ulna are ideally plated on their volar surfaces.
. The radius is ideally plated on its volar surface, and the ulna on its dorsal or medial surface.
. The plating surface depends solely on the fracture obliquity.

Correct Answer & Explanation

. The radius is ideally plated on its volar surface, and the ulna on its dorsal or medial surface.

Explanation

For the radius, the volar surface (anterior, Henry approach) is generally preferred (Option D) due to less soft tissue stripping and avoiding the posterior interosseous nerve. For the ulna, the subcutaneous dorsal surface (posterior) or the medial surface (which is also relatively subcutaneous) is preferred due to ease of access and minimal muscle dissection. Therefore, Option D, 'The radius is ideally plated on its volar surface, and the ulna on its dorsal or medial surface,' is the most accurate statement, representing optimal surgical approaches and minimizing complications.

Question 1550

Topic: Surgical Anatomy & Approaches

Which surgical approach for the ulna shaft is generally considered the safest and most direct, minimizing neurovascular risk?

. Anterior approach.
. Posterior (dorsal) subcutaneous approach.
. Medial approach.
. Lateral approach.
. Anteromedial approach.

Correct Answer & Explanation

. Posterior (dorsal) subcutaneous approach.

Explanation

The posterior (dorsal) subcutaneous approach (Option B) 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 reducing the risk of injury to neurovascular structures, which are typically located volarly or deep in the forearm. The anterior and medial approaches involve more muscle dissection and potential risks to vessels and nerves.

Question 1551

Topic: Surgical Anatomy & Approaches

Which artery is at highest risk of injury during the surgical approach to a distal radial shaft fracture via the Henry (anterior) approach?

. Ulnar artery.
. Posterior interosseous artery.
. Anterior interosseous artery.
. Radial artery.
. Brachial artery.

Correct Answer & Explanation

. Radial artery.

Explanation

The radial artery (Option D) lies in close proximity to the distal radial shaft and is directly within the surgical field of the Henry (anterior) approach. It must be carefully identified and retracted, typically ulnarward, to prevent iatrogenic injury. The ulnar artery (A), posterior interosseous artery (B), and anterior interosseous artery (C) are typically not in the direct field for a distal radial approach. The brachial artery (E) is much more proximal.

Question 1552

Topic: Surgical Anatomy & Approaches

Which approach is generally preferred for fixation of the distal radial shaft in a Galeazzi fracture due to superior exposure of the anterior radial surface and relative safety for the posterior interosseous nerve?

. Dorsal approach (Thompson approach)
. Ulnar approach
. Volar approach (Henry approach)
. Direct lateral approach
. Combined dorsal and volar approaches

Correct Answer & Explanation

. Volar approach (Henry approach)

Explanation

The volar approach (Henry approach) is generally preferred for fixation of distal radial shaft fractures, including Galeazzi fractures. It provides excellent exposure of the volar surface of the radius, where the plates are typically applied, and minimizes the risk to the posterior interosseous nerve (PIN), which is associated with the dorsal approach. The anterior interosseous nerve (AIN) is the primary structure at risk with the Henry approach, requiring careful identification and protection.

Question 1553

Topic: Surgical Anatomy & Approaches

A 55-year-old male undergoes ORIF with a locked compression plate for a humeral shaft fracture. Postoperatively, he develops a wrist drop and inability to extend his thumb and fingers at the MCP joints. Sensory examination reveals hypoesthesia in the dorsal aspect of the first web space. What is the most appropriate initial step in managing this complication?

. Immediate re-exploration of the radial nerve
. Obtain an EMG/NCS to confirm nerve injury
. Observe for spontaneous recovery over 3-6 months
. Administer high-dose corticosteroids
. Obtain a CT scan of the humerus to check for hardware impingement

Correct Answer & Explanation

. Immediate re-exploration of the radial nerve

Explanation

An iatrogenic radial nerve palsy (occurring after surgery) is an absolute indication for immediate surgical exploration. Unlike primary palsies that occur with the injury (which often recover spontaneously), iatrogenic palsies are more likely due to direct nerve transection, entrapment, or severe compression by hardware or retractors. Prompt exploration is crucial to identify and address the cause, which could involve nerve decompression, repair, or removal of offending hardware. Delaying exploration can lead to irreversible nerve damage. EMG/NCS and observation are appropriate for primary palsies, but not for iatrogenic palsies.

Question 1554

Topic: Surgical Anatomy & Approaches

A patient undergoing ORIF of a mid-humeral shaft fracture with a posterior approach is at greatest risk for iatrogenic injury to which of the following structures?

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

Correct Answer & Explanation

. Radial nerve

Explanation

The radial nerve is particularly vulnerable during surgical approaches to the humeral shaft, especially a posterior approach. It courses obliquely across the posterior aspect of the humerus, approximately 10-14 cm proximal to the lateral epicondyle, passing through the spiral groove. During a posterior approach (e.g., triceps-splitting or triceps-sparing), the radial nerve is at significant risk of direct injury, traction, or entrapment. Other nerves are less directly exposed or are more distal/proximal to the typical mid-shaft fracture zone when using a posterior approach.

Question 1555

Topic: Surgical Anatomy & Approaches

What is the most common nerve injured in humeral shaft fractures?

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

Correct Answer & Explanation

. Radial nerve

Explanation

The radial nerve is by far the most commonly injured nerve in humeral shaft fractures due to its close anatomical proximity as it winds around the humerus in the spiral groove. Incidence ranges from 8% to 15% with closed fractures. Injuries to other nerves are less common with humeral shaft fractures themselves, though the axillary nerve is more commonly injured with proximal humeral fractures, and the median/ulnar nerves with supracondylar or distal humeral fractures.

Question 1556

Topic: Surgical Anatomy & Approaches

Which of the following surgical approaches for humeral shaft fractures offers direct access to the radial nerve in the spiral groove, making it suitable for both fracture fixation and nerve exploration?

. Anterolateral approach (Henry approach)
. Posterior approach (triceps-sparing)
. Medial approach
. Deltopectoral approach
. Anterior approach (between biceps and brachialis)

Correct Answer & Explanation

. Posterior approach (triceps-sparing)

Explanation

The posterior approach to the humeral shaft (e.g., triceps-sparing or triceps-splitting) provides excellent direct visualization of the radial nerve in the spiral groove. This makes it a preferred approach when there is a known or suspected radial nerve injury that requires exploration in conjunction with fracture fixation. The anterolateral approach can allow for identification of the radial nerve more distally (after it exits the spiral groove) but the posterior approach offers the most direct and extensive visualization of the nerve along the mid-shaft. The other approaches are less suitable for consistent radial nerve exposure in this region.

Question 1557

Topic: Surgical Anatomy & Approaches

What is a potential complication specifically associated with the anterolateral approach (Henry approach) to the distal humeral shaft?

. Injury to the ulnar nerve
. Injury to the median nerve
. Injury to the musculocutaneous nerve or its terminal lateral antebrachial cutaneous branch
. Injury to the axillary nerve
. Postoperative stiffness of the shoulder

Correct Answer & Explanation

. Injury to the musculocutaneous nerve or its terminal lateral antebrachial cutaneous branch

Explanation

The anterolateral approach (Henry approach) for the distal humeral shaft involves dissection between the brachialis and the brachioradialis/extensor carpi radialis longus. The musculocutaneous nerve pierces the coracobrachialis proximally and then courses between the biceps and brachialis, innervating both. Distally, it becomes the lateral antebrachial cutaneous nerve. This nerve or its branches are at risk during this approach, particularly when dissecting through or around the brachialis muscle. Injury can lead to weakness in elbow flexion and sensory deficits in the lateral forearm. The other nerves are less directly exposed in this specific approach.

Question 1558

Topic: Surgical Anatomy & Approaches

Which of the following approaches is most appropriate for a fracture of the proximal third of the humeral shaft, particularly when proximal fixation is challenging?

. Posterior approach (triceps-sparing)
. Anterolateral approach (Henry approach)
. Deltopectoral approach
. Medial approach
. Direct lateral approach

Correct Answer & Explanation

. Deltopectoral approach

Explanation

The deltopectoral approach is the workhorse approach for proximal humeral fractures and the proximal third of the humeral shaft. It utilizes the interval between the deltoid and pectoralis major muscles, providing excellent access to the proximal humerus while preserving the axillary nerve. This approach allows for adequate exposure to apply a plate to the lateral or anterior aspect of the humerus, facilitating stable fixation, especially in fractures with extension into the proximal metaphysis. Other approaches are less suitable for the proximal third, either due to nerve risk (posterior, lateral) or limited exposure (anterolateral, medial).

Question 1559

Topic: Surgical Anatomy & Approaches

A patient is undergoing open reduction and internal fixation of a humeral shaft fracture. During plate application, the surgeon notices a dull, non-pulsatile ooze from a small vessel. Which vessel is most likely to be injured during standard plating of the mid-diaphysis?

. Brachial artery
. Profunda brachii artery
. Anterior circumflex humeral artery
. Posterior circumflex humeral artery
. Radial artery

Correct Answer & Explanation

. Profunda brachii artery

Explanation

The profunda brachii artery (deep brachial artery) and its accompanying veins run in the spiral groove alongside the radial nerve. During plate application to the mid-diaphysis (especially with posterior or anterolateral approaches), these vessels are at risk of injury. A dull, non-pulsatile ooze is characteristic of venous or smaller arterial branch injury. The brachial artery is larger and more anterior/medial. The circumflex humeral arteries are more proximal. The radial artery is distal to the fracture site at the forearm. Injury to the profunda brachii artery is a known, though usually manageable, complication of humeral shaft surgery.

Question 1560

Topic: Surgical Anatomy & Approaches

What is the typical timeframe for expected radial nerve recovery after a primary closed humeral shaft fracture with a complete radial nerve palsy?

. Within 1-2 weeks
. Within 3-6 months
. Within 9-12 months
. Over 12 months, if at all
. Immediate surgical exploration is always required

Correct Answer & Explanation

. Within 3-6 months

Explanation

For a primary radial nerve palsy associated with a closed humeral shaft fracture (neurapraxia or axonotmesis), the vast majority of patients (85-90%) will experience spontaneous recovery, typically beginning within 3-6 months. Observation for this period is the standard of care. If no signs of recovery are observed after 3-4 months, or if the palsy is iatrogenic or secondary (occurring after reduction), then surgical exploration may be indicated.

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