1. General Principles & Basic Science MCQs

A surgeon is performing an anterolateral approach to the humerus for plate fixation of a midshaft fracture.

To safely protect the radial nerve during this exposure, the surgeon must understand its anatomical course. At what approximate distance proximal to the lateral epicondyle does the radial nerve typically pierce the lateral intermuscular septum?

A surgeon is performing a posterior approach to the humerus for open reduction and internal fixation of a comminuted midshaft humerus fracture. What is the true internervous plane utilized in the distal aspect of the standard posterior approach?

A 29-year-old male sustains a closed, midshaft oblique humerus fracture after falling from a ladder. Examination in the emergency department reveals absent wrist extension, absent finger extension, and decreased sensation in the first dorsal web space. What is the most appropriate initial management of his nerve injury?

During an extensile posterior approach to the humerus for fracture fixation, identifying and protecting the radial nerve is critical. Based on standard anatomical landmarks, where does the radial nerve predictably cross the posterior aspect of the humerus before piercing the lateral intermuscular septum?

The radiograph below shows a severely displaced, comminuted fracture of the proximal third of the tibial diaphysis. This specific deformity pattern, characterized by apex anterior (procurvatum) and apex lateral (valgus) angulation, is classic for proximal third tibial fractures. Which of the following is the primary deforming force responsible for the apex anterior angulation of the proximal fragment?

A patient sustains a deep laceration over the anterior knee following a fall on shattered glass. A traumatic arthrotomy is suspected. A saline load test is performed to evaluate joint capsular integrity. According to the literature, what minimum volume of intra-articular normal saline is required to achieve a 95% sensitivity for detecting a traumatic arthrotomy of the knee?

An 18-year-old male sustains a suspected traumatic arthrotomy of the knee after a deep laceration from a chainsaw. In the emergency department, a saline load test is considered. According to recent literature, what is the most sensitive method for detecting a traumatic arthrotomy of the knee?

When evaluating a patient with a severely mangled lower extremity, the Mangled Extremity Severity Score (MESS) is often calculated to guide decision-making between salvage and amputation. Which of the following variables is weighted most heavily in the MESS scoring system?

A 30-year-old male suffers a high-energy crush injury to his forearm.

Which muscles are at the highest risk of ischemic necrosis due to their central and deep location in the volar forearm?

A 45-year-old male is undergoing prolonged vascular repair of the popliteal artery after a knee dislocation. Following revascularization, his leg rapidly swells and becomes tense. The pathogenesis of this reperfusion injury is most directly mediated by which of the following?

A 68-year-old female presents with a displaced 3-part proximal humerus fracture following a fall. She is scheduled for open reduction and internal fixation via a deltopectoral approach. During the deep dissection, after identifying the cephalic vein and retracting the deltoid laterally and pectoralis major medially, the surgeon proceeds to manage the subscapularis to gain access to the humeral head. Which of the following neurovascular structures is at greatest risk during the inferior aspect of this exposure, particularly when mobilizing the deltoid or performing extensive inferior dissection?

A 60-year-old male presents with a non-union of the mid-shaft humerus, previously treated non-operatively. He is scheduled for revision ORIF via an anterior approach. During the deep dissection, the surgeon identifies the biceps brachii and brachialis muscles. To access the humeral shaft, the surgeon plans to split the brachialis muscle longitudinally in its distal portion. Which nerve is primarily responsible for innervating the brachialis muscle and must be protected during this maneuver?

A 48-year-old male undergoes ORIF of a comminuted humeral shaft fracture via an anterolateral approach. Post-operatively, he develops a new complete radial nerve palsy. The surgeon decides to observe the patient for initial recovery. Based on the case content, what is the typical expected recovery period for most radial nerve palsies following humeral shaft fracture fixation?

During a posterior approach to the humerus for internal fixation of a diaphyseal fracture, the surgeon must identify and protect the radial nerve. On average, at what distance from the relevant bony landmarks does the radial nerve cross the posterior aspect of the humerus in the spiral groove?

A 40-year-old male undergoes open reduction and internal fixation of a humeral shaft fracture via an anterolateral approach. During the distal extension of this approach, which two muscles form the internervous plane?

A surgeon is performing a Kaplan (anterolateral) approach to the elbow for a complex radial head fracture. The internervous plane utilized in this approach lies between which two muscles?

A 42-year-old male is recovering from a humeral shaft fracture complicated by a primary radial nerve palsy. The surgeon monitors him clinically for signs of nerve recovery. Assuming normal progression of reinnervation, which muscle will be the FIRST to exhibit returning motor function?

When performing an extensile posterior approach to the humerus using a triceps-splitting technique, the surgeon must be careful to avoid denervating the medial head of the triceps. Which branch of the radial nerve is at greatest risk during the distal split of the triceps muscle?

A patient is scheduled for ORIF of a proximal humerus fracture via a standard deltopectoral approach. During the deep dissection, the surgeon visualizes the conjoined tendon. Retraction of the conjoined tendon medially places which neurological structure at highest risk?