Innervation of the spinal dura mater

The nerve supply to the spinal dura mater has long been a subject of controversy. Von Luschka (1850), in his classic monograph, described a series of nerves which passed through the intervertebral foramina. Each nerve corre-sponded with one foramen and traversed it ventral to the spinal nerve. He traced this recurrent nerve by gross dissection and noted that, within the spinal canal, it supplied the bone and blood vessels. Hence it was named the sinu-vertebral nerve (now termed ramus meningeus P.N.A.). Luschka ob-served that branches of each ramus meningeus remained entirely outside the spinal dura mater although some were seen close to its surface. Other contemporary workers, notably Piirkinje (1845), saw no epidural nerves piercing the dura. Rudinger (1857), however, dissected nerves which ran along the ventral surface of the dura mater and then entered it. Some fibres were found to be peri-vascular, others to pursue an independent course. Further studies by other workers, reviewed by Testut (1930), confirmed these findings. By 1904 the presence of intrinsic nerves of the spinal dura mater was well enough established for Poirier and Charpy to describe them in their textbook. Hove-lacque (1925), Pederson, Blunck, and Gardner (1956), and Stilwell (1956), by various methods, including gross dissection and examination of stained serial sections, identified the presence of nerves which penetrated the spinal dura mater. However, contrary to a century of agreed findings, Bridge (1959) stated definitely that the spinal dura mater, unlike its cranial counterpart (Penfield and McNaughton, 1940), had no intrinsic nerve supply; epidural nerves were seen to end on the dural surface only. Kimmel's recent study (1961) of Bodian-stained foetal sections, however, demonstrated intrinsic nerve fibres. He concluded that these were only to be seen with difficulty and that the different con-clusions reached by previous workers were due to the varying quality of their preparations. The origin of nerve fibres supplying the dura (whether they are confined to its surface or are truly intrinsic) is generally agreed to be from the mening-