<prompt> Given video shows findings of an abnormality. The patient has most likely suffered lesion at which level?Radial grooveLower 13 of forearmNeck of radiusAt wrist  <response>: Low Radial nerve palsy: Injury is before the spiral groove. All muscles supplied by radial nerve are paralysed. Low radial nerve injuries may be of two types:- 1 Type 1: Injury occurs between the spiral groove and elbow joint. Muscles involved is:- Elbow extensorsTriceps,Anconeus are spared. Wrist, elbow and finger extensors are paralysed. Sensory loss in first web spaceon dorsal side. 2Type 2:-Injury occurs below the elbow joint. Elbow extensors,brachioradialis and wrist extensorsECRLare spared. Finger extensors extensor digitorum,extensor digiti minimi,extensor indicis,ECRB and thumb extensorsextensor pollicis longus brevisare paralysed. Sensory loss in the first web spaceon dorsal side. 