<prompt> Injury to radial nerve in lower part of spiral groove-Spares nerve supply to extensor carpi radialis longusResults in paralysis of anconeus muscleLeaves extensions at elbow joint intactWeakens pronation movement  <response>: Radial nerve injury- High radial nerve palsy- Injury above the spiral groove. Paralysis of all muscles supplied by radial nerve. Clinical features Wrist drop, finger drop, thumb drop Extension affected of- elbow, wrist, thumb and fingers Sensation affected of- posterior surface of arm and forearm and lower lateral half of forearm.- Low radial nerve palsy- Injury below the spiral groove. Type I- Injury between spiral groove and elbow. Elbow extensors are spared- Triceps and Anconeus. Wrist, thumb and finger extensors paralysed- wrist drop, thumb drop, finger drop. Loss of sensation on dorsal side of first web space. Type II- Injury below the elbow joint. Elbow and wrist extensors spared Thumb and finger extensors paralysed.extensor digitorum, extensor digiti minimi, extensor indicis, extensor pollicis longus, extensor pollicis brevis- Thumb drop and finger drop. Loss of sensation on dorsal side of first web space. 