Sacroiliac joint innervation and pain.

The present paper reviews current knowledge on the innervation of the human sacroiliac joint (SIJ). We conclude, based on a recent anatomic study on adult cadavers, with fetal correlation, that the joint is predominantly, if not entirely, innervated by sacral dorsal rami. This conclusion is in agreement with patterns of referred pain reported by asymptomatic volunteers upon direct SIJ capsular stimulation and with a reduction in pain in patients treated for (presumptive) SIJ pain by injection of an anesthetic into the SIJ. We also present preliminary data suggesting that the periarticular tissues of the SIJ, like those of other synovial joints, contain mechanoreceptors and nociceptors that function to inform the central nervous system about the state of the joint.