Muscle relaxants are essential in anaesthesia for neuroradiological diagnosis. In addition, neurosurgical and neurological patients often face, because of their basic illness, respiratory danger, which can increase postoperatively through the use of muscle relaxants during anaesthesia. Because of their pharmacodynamic properties and side-effects, muscle relaxants must be clearly differentiated from one another and used selectively for the different phases of anaesthesia-intubation, calmness during examination and recovery from neuromuscular block with extubation. During planned extubation in particular, no residual relaxation or danger of recurarization must exist during the recovery stage from neuromuscular block. For investigations with planned extubation, only the muscle relaxants atracurium and vecuronium with their medium-long effect should be applied. A high degree of safety is provided by neuromuscular block and especially in the recovery phase. Using relaxometers it is possible to determine individual relaxant requirements, avoid under- and overdoses, carry out an antagonism at the correct time and prevent residual relaxation situations so that respiratory insufficiency can be reliably excluded.