Radial Nerve — Course and Lesions

A 28-year-old man sustains a penetrating injury to the posterior arm during a knife attack. Clinical examination reveals wrist drop and loss of thumb extension. Which is the most common cause of radial nerve injury in penetrating trauma to the upper limb?

A 32-year-old man presents with a fracture of the mid-shaft of the humerus following a motor vehicle accident. Which is the most common site of radial nerve injury in humeral shaft fractures?

A 28-year-old construction worker sustains a fracture-dislocation of the shoulder with posterior displacement. Which is the most common cause of radial nerve injury in proximal humeral fractures?

A 28-year-old woman is brought to the orthopedic clinic 8 weeks after a mid-shaft humerus fracture treated conservatively with a functional brace. She reports persistent wrist drop and inability to extend her fingers. On examination, there is no improvement in radial nerve motor function compared to the initial injury. Sensory examination shows continued loss over the dorsal first web space. What is the most appropriate next step?

A patient sustains a fracture of the mid-shaft humerus and develops wrist drop with inability to extend the fingers at the metacarpophalangeal joints. Which branch of the radial nerve is responsible for innervating the muscles that produce these movements?