Sensory Innervation of the Sacroiliac Joint

Abstract

The sacroiliac joint (SIG) has a special position due to its location, its structure, its importance for the upright gait and its innervation. Anatomy and sensory supply are laterally asymmetrical. The sacral and ileal parts are different in terms of cartilage covering, bony support and susceptibility to pathology, but the ligamentous apparatus is more important and extensive. Especially its dorsal supply via the dorsal sacral plexus is significant and occurs essentially via L5-S4. Little is known about the vegetative innervation; zones of referenced pain are nonspecific. The very extensive sensory innervation suggests a joint much more oriented to motion than to load transmission. The perpetuated view of amphiarthrosis as a preferably statically oriented joint needs to be expanded to better understand pain generated here. In this way, the newer knowledge about the correlation between pain and propriosensation can be better utilized diagnostically. For therapeutic accessibility, knowledge of the course of the nerve fibers is relevant: The supplying branches converge at the level of the anlage segment S2 and preferably enter the ligamenta at the same level via the crista sacralis lateralis close to the bone. Other spinal nerves take connection to the lateral nerve arches, whereby a more supraregional supply than with the facet joints becomes recognizable.