<prompt> In epidural anaesthesia drug is injectedOutside the duraInside the duramaterInside arachnoidamaterinside piamater  <response>: Epidural extradural anaesthesiaLocal anaesthetic is injected in epidural space, i.e., outside the dura mater with Tuohy;s needleIn extradural space, LA acts on the nerve rootsIt is used in thoracic, lumbar and sacral caudal regions in contrast to spinal anaesthesia which is given in lumbar regionContinuous analgesia is achieved by mixing the LA with an opioid, eg fentanylIt is mainly used to control postoperative pain by continuous epidural anaesthesiaIt can also b used for all surgeries which can be performed under spinal anaesthesia.Refer: stoeltings pharmacology and physiology in anaesthetic practice, 5th edition, pg no.189 