7. Hand and Wrist MCQs

A 28-year-old competitive cyclist presents with isolated weakness in pinching (adductor pollicis) and finger abduction/adduction, but reports normal sensation in the little and ring fingers. A ganglion cyst is suspected to be compressing the deep motor branch of the ulnar nerve. Where does this branch typically course immediately after bifurcating from the main ulnar nerve in Guyon's canal?

Following closed reduction and percutaneous pinning of a displaced pediatric supracondylar humerus fracture, the child is unable to actively flex the interphalangeal joint of the thumb or the distal interphalangeal joint of the index finger. Sensation in the hand remains intact. Which of the following best describes the anatomical course of the injured nerve?

During an anterior (Henry) approach to the radius for internal fixation of a midshaft fracture, the surgeon develops the interval between the brachioradialis and flexor carpi radialis. To expose the proximal radius, the supinator muscle must be elevated. What nerve must be protected, and how is it anatomically safeguarded during this specific step?

A 30-year-old construction worker undergoes surgical exploration and debridement for a deep space infection of the hand. Purulent fluid is drained exclusively from the midpalmar space. The midpalmar space is anatomically separated from the thenar space by which of the following structures?

A 32-year-old man sustains a deep laceration at the medial aspect of the elbow, resulting in a complete transection of the ulnar nerve. On physical examination weeks later, he surprisingly demonstrates preserved motor function of the first dorsal interosseous, adductor pollicis, and the deep head of the flexor pollicis brevis, despite absolute loss of ulnar sensation. Which of the following anatomical variants is most likely responsible for this preserved motor function?

A 28-year-old carpenter suffers a deep laceration to the volar aspect of the wrist, immediately proximal to the wrist crease and directly overlying the flexor carpi radialis (FCR) tendon. Exploration confirms a complete transection of the FCR. Which neural structure is at the highest risk of concomitant injury due to its intimate anatomical relationship with the FCR tendon at this level?

A 35-year-old new mother undergoes surgical release for recalcitrant De Quervain's tenosynovitis. During the release of the first dorsal compartment, the surgeon notes anatomical variations. Which of the following tendon structures most commonly has multiple distal slips that must be completely visualized to prevent surgical failure?

A 40-year-old carpenter complains of a progressive inability to cross his index and middle fingers, associated with numbness over the volar aspect of his small finger. Symptoms are exacerbated with prolonged elbow flexion. The nerve responsible for these findings passes between which two muscle heads in the proximal forearm?

The scaphoid bone is highly susceptible to avascular necrosis following a proximal pole fracture due to its retrograde blood supply. Which of the following arterial branches is the primary source of blood supply to the proximal pole of the scaphoid?

The recurrent motor branch of the median nerve innervates the thenar musculature. When performing an open carpal tunnel release, the surgeon must be aware of anatomical variations of this branch. What is the most common anatomical variation (occurring in >50% of the population) of the recurrent motor branch relative to the transverse carpal ligament?

A 28-year-old professional rock climber presents with acute pain and a 'bowstringing' deformity over the volar aspect of his left ring finger after slipping on a hold. He is diagnosed with a severe flexor pulley rupture. Which of the following best describes the most biomechanically critical pulleys to prevent flexor tendon bowstringing, and their correct anatomical origins?

A 45-year-old woman presents with a 4-month history of vague proximal anterior forearm pain, weakness with pinching, and numbness in her thumb, index, and middle fingers. On examination, she has decreased sensation over both the palmar digits and the thenar eminence. Radiographs of the elbow reveal an osseous spur on the anteromedial aspect of the distal humerus. Neural compression is most likely occurring as the nerve passes deep to which of the following structures?

Which pulleys in the flexor tendon sheath of the digits are most critical to preserve in order to prevent mechanical bowstringing?

A 45-year-old man presents with numbness in his ring and small fingers and weakness in his intrinsic hand muscles. EMG testing localizes compression of the ulnar nerve in the distal arm. Which of the following structures is most likely responsible for this compression?

A 25-year-old woman presents with dorsal wrist pain with extension. Examination reveals swelling and tenderness over the 4th dorsal extensor compartment. Which of the following structures are contained within this compartment?

A 12-year-old child presents with vague forearm pain and weakness in thumb flexion and forearm pronation. Radiographs reveal a bony spur on the anteromedial humerus, 5 cm proximal to the medial epicondyle. Which structure is most likely compressed by the ligament connecting this spur to the medial epicondyle?

A cyclist presents with weakness in finger abduction and adduction, but normal sensation in the little and ring fingers. A lesion in Guyon's canal is suspected. At which specific zone of Guyon's canal is the compression most likely located?

A 45-year-old patient sustains a nondisplaced distal radius fracture and is treated in a cast. Six weeks later, she presents with sudden inability to extend her thumb interphalangeal joint. The ruptured tendon normally travels in which extensor compartment, and what is its radial boundary?

Which of the following statements most accurately describes the primary blood supply to the scaphoid, predisposing it to proximal pole avascular necrosis?

Within Guyon's canal, the ulnar nerve bifurcates into superficial and deep branches. The deep branch dives into the hand by passing between which two muscular structures?