Early reports on the innervation of the spinal column suggested that spinal spino-vertebral nerves innervated bone and vascular structures without penetrating the dura mater (1). This rationalised the teaching during the last millennium that dural puncture was painless (2). Subsequent studies, however, showed that the anterior aspect of the dura mater also has a nerve supply (3,4), and that sensory nerves from the dorsal root ganglion innervate the lumbar epidural membrane and lumbar dura mater (5,6). Coincidental with these findings has been the introduction and popularisation of combined spinal-epidural analgesia (CSEA) for labour analgesia, caesarean section and other surgery below the costal margin. The 'needle-through-needle' CSEA technique has several advantages. Technically, it facilitates insertion of small-gauge spinal needles through the meninges via the epidural needle. Clinically, it produces rapid onset of analgesia following intrathecal injection of local anaesthetic, has the facility to supplement or augment inadequate spinal block by epidural injection via the epidural catheter of additional local anaesthetic and can provide postoperative epidural analgesia by infusion of local anaesthetic solution. An additional benefit is that it enables direct observation of the responses of conscious patients to stimulation of their posterior spinal meninges during insertion of the spinal needle through the meninges.