Surgical Anatomy & Approaches MCQs

The direct anterior (Smith-Petersen) approach to the hip is increasingly popular for THA. This approach utilizes a superficial internervous plane between which of the following muscles?

When utilizing the direct anterior approach (DAA) for a primary total hip arthroplasty, the superficial surgical dissection utilizes an internervous plane. Which of the following pairs of muscles defines this interval?

During an anterolateral approach for internal fixation of a proximal humerus fracture, the axillary nerve is at significant risk of iatrogenic injury. What is the average distance of the axillary nerve from the lateral edge of the acromion?

A 42-year-old female sustains a Bryan and Morrey Type I capitellar fracture. During ORIF, headless compression screws are to be placed anterior-to-posterior. Which surgical approach provides the most direct anterior access while minimizing the risk to the lateral ulnar collateral ligament (LUCL)?

The standard volar (Henry) approach to the radius utilizes a continuous internervous plane along the forearm. In the proximal third of the forearm, this approach separates the pronator teres and the brachioradialis. Which nerves supply these two muscles, respectively?

A patient sustains a closed midshaft humerus fracture resulting in a radial nerve palsy. According to the Sunderland classification of peripheral nerve injuries, a third-degree injury is characterized by the disruption of the axon and which other structural element(s)?

A 35-year-old patient presents with a radial nerve palsy following a closed humeral shaft fracture. The physician elects to observe the injury but orders an electromyography (EMG) study to evaluate for axonal loss. What is the minimum time after the injury that fibrillation potentials will reliably appear on an EMG?

A patient sustains an injury leading to profound weakness in thigh adduction and a small area of sensory loss over the medial middle third of the thigh. Which nerve is most likely injured, and through which pelvic foramen does it exit?

When performing an open subpectoral biceps tenodesis, deep retraction is required to expose the humerus. If retractors are placed too far medially, which nerve is at greatest risk of iatrogenic injury?

A 30-year-old male weightlifter complains of poorly localized posterior shoulder pain and numbness over the lateral deltoid. Physical examination reveals focal point tenderness in the quadrilateral space. Which vascular structure is at risk of compression in this space alongside the affected nerve?

A patient sustains a closed midshaft humerus fracture and presents with a complete radial nerve palsy. Assuming a Sunderland first-degree injury (neurapraxia), what is the primary pathophysiological mechanism responsible for the conduction block?

A 28-year-old male presents with a closed, mid-shaft transverse humerus fracture following an arm-wrestling injury. On initial examination, he has an isolated radial nerve palsy. What is the most appropriate initial management for his nerve injury?

During an ilioinguinal approach for the fixation of an anterior column acetabular fracture, significant arterial hemorrhage is encountered upon dissection over the superior pubic ramus. This bleeding is most likely originating from an aberrant anastomotic vessel known as the 'corona mortis'. Between which two vascular systems does this anastomosis typically occur?

A patient sustains a closed humerus fracture and presents with a radial nerve palsy. Electromyography at 4 weeks shows fibrillation potentials but no motor unit action potentials. If this represents a Sunderland third-degree nerve injury, which of the following structures remains intact?

Following a closed midshaft humerus fracture, a patient develops a complete radial nerve palsy. Electromyography (EMG) performed at 4 weeks shows fibrillation potentials in the brachioradialis. If the nerve has sustained an injury where the axon and myelin sheath are disrupted, but the endoneurium, perineurium, and epineurium remain anatomically intact, this corresponds to which classification?

A patient sustains a mid-shaft humerus fracture resulting in a radial nerve palsy. Electromyography at 4 weeks shows fibrillation potentials in the brachioradialis, but the nerve sheath is presumed intact. According to Seddon's classification, this injury is best categorized as:

A patient sustains a closed mid-shaft humerus fracture and subsequent radial nerve palsy. Electromyography at 4 weeks reveals fibrillation potentials in the extensor muscles. Theoretical microscopic evaluation shows Wallerian degeneration, but the endoneurial tubes remain intact. According to the Sunderland classification, what grade of nerve injury is this?