<prompt> Wrist drop is due to injury of -Ulnar nerveRadial nerveMedian nerveMusculocutaneous nerve  <response>: Radial nerve injury- High radial nerve palsy- Injury above the spiral groove.o Paralysis of all muscles supplied by radial nerve.o Clinical featuresWrist drop, finger drop, thumb dropExtension affected of- elbow, wrist, thumb and fingersSensation affected of- posterior surface of arm and forearm and lower lateral half of forearm.- Low radial nerve palsy- Injury below the spiral groove.o 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.o Type II- Injury below the elbow joint.Elbow and wrist extensors sparedThumb 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. 