The term “lumbar eye” refers to two relatively symmetrical depressions in the skin surface that can be seen on our waist. In some people it is very obvious, in others it is not obvious, or even completely invisible. The reason for this is that the posterior superior iliac spine is the attachment point for many tendons, and in some people, the tendons are more tightly bonded to the skin, so the skin can be seen to be sunken in the upright position. In some people, the tendons are not so tightly bound to the skin, or the subcutaneous fat is thicker, so it can not be seen. The lumbar eye is only an anatomical landmark for clinical treatment, but not a guide for some diseases or treatments.