Illustration of the technique of giving a spinal epidural anaesthetic, showing a hypodermic syringe inserted between two vertebrae to inject an anaesthetic into the epidural space, the space between the dura mater of the spinal cord and the vertebral canal. Spinal anaesthesia is given to patient's whose condition precludes using general anaesthesia - perhaps because of a chest infection. The technique is frequently used to administer narcotic analgesics (morphine) to women in labour, since it produces less sedation than do analgesics given intravenously.