Sacroiliac joint, but there are also a few ligaments that connect the two bones.
I think the sacrum and coxal bone are joined at the sacroiliac joint.
The joint between the sacrum and the hip bone is the sacroiliac joint. It is also known as the SI joint. They form the articular surfaces.
sacrum
Ilium - you have one either side of your midline. The continue from the sacrum at the back to the pubis at the front. The uppermost part is called the iliac crest. You can normally feel the Anterior Superior Iliac spine as your front "hip bone" and the Posterior Superior Iliac spine as your rear "hip bone" - they are different parts of the same continuous bone.
sclerosis means thickening or hardening of the bone I have diffuse formed sclerosis of the left iliac of the sacroiliac joint, doctor told me this is Arthritis.
It is the sacrum.
The spine (specifically L5, the 5th lumbar vertebra). The pelvis also attaches to the sacrum but I think that joint is fused.
A sclerotic bone lesion is a tumor that forms on bone. If it is found on the iliac bone, it is simply a lesion or tumor that has rooted itself onto the iliac bone.
The hipbones are united anteriorly at a joint called the pelvic symphysis
You are probably asking about the sacrum, which is 6 bones that fuse together as a child matures. This is not an arthropoidal joint like the knee or elbow that rotates around. There are strips of super-slick tissue on the hip bone that allow the sacrum to shift slightly. These can become damaged or worn, and cause considerable pain.
Iliac Crest This is the superior margin of the coxal bone.
The sacrum is a large triangular bone at the base of the spine.