The cause of a lumbar or sacroiliac pain is usually never the sacroiliac joint, but it always seems to be another major cause. The nerve par excellence of the sacroiliac joint, as experts say Osteopathy is the obturator nerve, which is a visceral nerve. It is also the nerve, for example, the bowel or ovarian.
It is a good joint to learn to manipulate, but really solves little cause pain and if handled. For example, performing the typical Gillet test, if a second inhibit any viscera therapist can verify that the test changes completely.
In the event that there is a sacroiliac pain long, there is a fibrosis of the sacroiliac ligaments. Cluneos have nerves (interesting for osteopathic treatment of urogenital sphere) that give small fibers that are also going to the sacroiliac joints.
The top of the ribs is cluneos iliohypogastric, a visceral nerve such as shutter lumbar plexus.
So, blockades of the sacroiliac joints are a reflection of dysfunctions of the organs located above the sacroiliac.