Lumbar Disc Herniation
The disc wall can crack under sustained pressure, allowing the inner nucleus to bulge outward. When this impinges on a nerve root, it causes sharp, radiating pain that travels into the buttock and down the leg — the classic presentation of sciatica. Disc herniation is particularly common at the L4/L5 and L5/S1 levels.
Lumbar Facet Joint Syndrome
Each vertebra has two pairs of small facet joints at its rear. These joints guide spinal movement. When they become restricted or inflamed, they create a characteristic deep ache in the lower back that may refer pain into the hips and thighs. The pain typically worsens when you stand or arch your back and eases when you sit.
Sacroiliac Joint Dysfunction
The sacroiliac joint connects the sacrum to the ileum of the pelvis. It moves very little, but when it is hypermobile or restricted, it creates pain localised to the buttock and the back of the thigh. This is commonly misdiagnosed as a disc problem.
Muscle Strain
Lifting, twisting, bending awkwardly, or simply reaching in an unguarded way can strain the muscles and ligaments of the lower back. The resulting muscle spasm is your body’s protective response, but it often compounds the pain and limits movement.
Spinal Stenosis
In some adults, particularly from middle age onwards, the spinal canal narrows due to arthritic changes. This can compress the nerve roots, causing pain and leg weakness that worsens with walking and standing, and eases when you sit or bend forward.
Spondylolisthesis
This is a condition in which one vertebra slips forward over the one below it. It can be congenital or result from degenerative changes and frequently causes persistent lower back pain and buttock discomfort.