A 45-year-old man presents with inability to extend his wrist and fingers after falling asleep with his arm draped over a chair (“Saturday night palsy”). Sensation is impaired over the first dorsal web space. Which nerve is most likely injured?

A patient cannot make an “OK” sign with thumb and index finger. Which nerve is most likely injured?

A 32-year-old carpenter presents with weakness of thumb abduction and thenar muscle wasting. Tinel’s sign is positive at the wrist. Sensation is reduced over the lateral 3½ digits on the palmar surface. What is the most likely diagnosis?

A patient with a supracondylar fracture of the humerus develops inability to flex the interphalangeal joint of the thumb. Which structure is most likely injured?

A 28-year-old woman presents with clawing of the 4th and 5th fingers, weakness of finger abduction/adduction, and sensory loss over the medial 1½ fingers. Froment’s sign is positive. Which nerve is injured?

A motorcyclist sustains a mid-shaft humeral fracture. On examination, he cannot extend his thumb and has wrist drop. Which anatomical structure is at greatest risk in this type of fracture?

During carpal tunnel release surgery, which structure is at greatest risk of iatrogenic injury?

A patient presents with a laceration at the wrist and develops inability to adduct the thumb (positive Froment’s sign) but can oppose the thumb. Sensation over the thenar eminence is intact. Which nerve is most likely injured?

A 55-year-old diabetic patient presents with inability to flex the DIP joints of the index and middle fingers, but the ring and little fingers flex normally. FDP function to which fingers is affected, and what is the nerve involved?

A patient with a distal radius fracture develops severe pain, swelling, and progressive finger stiffness. On examination, there is pain on passive finger extension and weakness of thumb opposition with sensory loss over the lateral 3½ digits. What is the most concerning complication?

A 42-year-old presents post-humeral fracture with wrist drop but preserved triceps function and normal sensation over the posterior forearm. Finger extension at MCP joints is absent, but IP joint extension is preserved when the wrist is passively flexed. What is the most precise localization?

A 58-year-old with chronic kidney disease on hemodialysis develops progressive weakness of finger flexion and thumb opposition. Sensation is normal throughout. Electromyography shows denervation in flexor pollicis longus, pronator quadratus, and abductor pollicis brevis, but flexor carpi radialis is spared. What is the anatomical explanation?

During a forearm laceration repair, a patient develops isolated weakness of FDP to the index finger and loss of thumb IP flexion, with no sensory deficit. However, the surgeon notes the patient can still pronate the forearm against resistance. What is the most likely anatomical variant present?

A 35-year-old cyclist with handlebar palsy presents with weakness of finger abduction/adduction and hypothenar atrophy. Clawing is absent in the 4th and 5th digits. Sensation is lost over the palmar surface of the medial 1½ digits but preserved on the dorsal surface. Where is the lesion?

A 29-year-old man sustains a stab wound to the upper medial arm. He develops Froment’s sign and weak finger abduction, but surprisingly has normal FDP function to ring and little fingers and normal sensation throughout the hand. What anatomical anomaly best explains these findings?

A patient presents with inability to flex the DIP of the middle finger only, while index, ring, and little finger DIP flexion is intact. Thumb IP flexion is normal. Which anatomical variation is most likely present?

A 47-year-old diabetic presents with “pseudo-ulnar claw hand” – clawing of index and middle fingers with sparing of ring and little fingers. There is weakness of thumb IP flexion and index/middle DIP flexion. Intrinsic hand muscle function is normal. What is the diagnosis?

A motorcyclist with a humeral shaft fracture undergoes ORIF. Post-operatively, he has complete wrist drop and cannot extend fingers, but surprisingly has preserved triceps AND preserved brachioradialis function. Sensation over the first dorsal webspace is diminished. What is the most likely explanation?

A 52-year-old presents with thenar atrophy and weak thumb opposition. However, Phalen’s test is negative, Tinel’s sign at the wrist is negative, and two-point discrimination over the index and middle fingers is normal. Abductor pollicis brevis is weak but flexor pollicis longus is strong. EMG shows denervation only in thenar muscles. What is the most likely diagnosis?

A competitive arm wrestler develops progressive weakness of wrist flexion and finger flexion with fasciculations in the forearm. Sensation is intact. MRI shows an accessory muscle belly in the proximal forearm compressing the median nerve between the two heads of pronator teres. Which additional clinical finding would most strongly support the diagnosis of pronator syndrome over carpal tunnel syndrome?