Skip to content

Lumbosacral Region of the Spine

Font Size

Topic Overview

The spine is composed of 33 interlocking bones called vertebrae. The lumbosacral region of the spine camera.gif (or lumbar spine) consists of 5 lumbar vertebrae and 5 sacral vertebrae. The sacral vertebrae, which are fused together, are called the sacrum.

  • The lumbar vertebrae of the spine extend from the bottom of the rib cage to the sacrum.
  • The fifth lumbar vertebra is connected to the sacrum. The sacrum is connected to the pelvic bones and the tailbone (coccyx).
  • Because this part of the spine bears the weight and stress of the trunk and upper body, the lumbar vertebrae are larger and thicker than those in any other part of the spine.

A disc is located between each pair of lumbar vertebrae. The discs are capsules of connective tissue with a soft, jellylike center. The discs absorb shock and make the spine flexible. The bones of the sacrum are joined to one another and have no discs between them.

The vertebrae are supported by ropy tissues called ligaments and groups of muscles:

  • Abdominal (belly) muscles support the spine from the front and sides of the body.
  • Iliopsoas muscles support the spine and flex the hips.
  • Erector spinae muscles support the back of the trunk and spine and are the major stabilizers of the spine during lifting.

The spinal cord runs through the spinal canal, a tunnel that is formed by the holes in the center of each of the vertebrae. Nerves branch from the spinal cord, pass through openings (foraminae) between the vertebrae, and branch to the lower body.

1

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
Next Article:

Lumbosacral Region of the Spine Topics

Hot Topics

WebMD Video: Now Playing

Click here to wach video: Dirty Truth About Hand Washing

Which sex is the worst about washing up? Why is it so important? We’ve got the dirty truth on how and when to wash your hands.

Click here to watch video: Dirty Truth About Hand Washing

Popular Slideshows & Tools on WebMD

MS Overview
Recognizing symptoms.
feet
Solutions for 19 types.
pregnancy test and calendar
Helping you get pregnant.
build a better butt
How to build a better butt.
lone star tick
How to identify that bite.
woman standing behind curtains
How it affects you.
brain scan with soda
Tips to avoid complications.
row of colored highlighter pens
Tips for living better.
psoriasis
How to keep flares at bay.
woman dreaming
What Do Your Dreams Say About You?
spinal compression fracture
Treatment options.

Women's Health Newsletter

Find out what women really need.