Lordosis is an abnormal curvature of the spine that causes an inward curve of the lower back. It can be caused by conditions like achondroplasia, spondylolisthesis, osteoporosis, obesity, kyphosis, discitis, or benign juvenile lordosis. Symptoms vary depending on the cause but may include prominence of the buttocks. Lordosis is diagnosed through medical history, physical exam, and tests like x-rays, bone scans, MRI, CT scans, and blood tests. Treatment depends on the individual and cause but aims to stop curve progression and prevent deformity, sometimes through exercises or treatment of the underlying condition.