Bone
Typical lumbar vertebra
Large lower-back vertebra adapted for substantial loading
High-yield
Lumbar vertebrae normally lack cervical-type transverse foramina and thoracic rib facets. The pars interarticularis bridges the articular regions; it forms the neck of the familiar dog-like outline on an oblique radiograph.
Overview
The usual five lumbar vertebrae have broad bodies, thick arches and stout spinous processes. Their size helps carry the upper body's load, while discs and facet joints distribute movement between neighboring levels.
Reference facts
- Bone type
- Irregular bone of the lumbar spine
- Key landmarks
- Broad kidney-like body; short, thick spinous process; mammillary processes behind the superior articular regions; accessory processes near transverse-process bases; pars interarticularis
- Articulations
- Adjacent vertebrae through discs and facet joints; L5 joins the sacrum at L5–S1
Clinical correlation
The direction of a lumbar disc herniation affects which nerve root is compressed. At L4–L5, a paracentral herniation often affects the traversing L5 root, while a far-lateral one may affect the exiting L4 root.
Frequently asked questions
What type of bone is the typical lumbar vertebra?
The typical lumbar vertebra is an irregular bone of the lumbar spine bone.
What does the typical lumbar vertebra articulate with?
Adjacent vertebrae through discs and facet joints; L5 joins the sacrum at L5–S1.
What are the key landmarks of the typical lumbar vertebra?
Broad kidney-like body; short, thick spinous process; mammillary processes behind the superior articular regions; accessory processes near transverse-process bases; pars interarticularis.