S3 (Pelvis)

Located below the S2, The S3 vertebra is the third of five fused vertebrae that make up the sacrum. The sacrum is a triangular bone located at the base of the spine, between the two hip bones, and forms the back wall of the pelvic cavity. The S3 vertebra plays an important role in providing stability to the pelvis and supporting the weight of the upper body. It also serves as an attachment point for muscles and ligaments that help to maintain the posture and movement of the lower back, hips, and legs. S3 nerves primarily affect the medial buttock.