The line connecting the highest points of the iliac crests on both sides is flat against the spinous process of the 4th lumbar vertebra.
The iliac crest and posterior superior iliac spine, the iliac crest is the upper edge of the iliac wing, S-shaped curvature, the anterior concave to the inside, the posterior concave to the outside, the highest point of the iliac crest on both sides of the line of the highest point of the iliac crest flat on the 4th lumbar vertebral spinous process, it is the counting lumbar vertebrae of the bony signs.
The posterior superior iliac spine is a protrusion of the posterior end of the iliac crest. The anterior superior iliac spine is located at the anterior end of the iliac crest, and the highest point of the iliac crest is the iliac node when a person is standing upright. The iliac crest and anterior superior iliac spine are common sites for bone marrow aspiration.
Normally the line between the highest points of the two iliac crests is flat against the 4th and 5th lumbar discs, but if osteoporosis is present in the elderly, this position may gradually rise and is a diagnostic sign.