L5-S1 consists of the last bone in the lumbar spine (low back), called L5, and the triangle-shaped bone under it, known as the sacrum. The sacrum is made of five fused bones—S1 is at the top.

Gbolabo Sokunbi, a spine surgeon at the Hospital for Special Surgery in Manhattan. Then lift from your legs instead of your arms and back, he said. Keep heavier items close to your body when ...

Low back pain is one of the most common reasons patients see primary care doctors. To understand this condition, it’s ...