The Anatomy of the Lumbar Spine

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The low back is the part of the spinal column that consists of the lumbar spine, the sacrum, and the coccyx.

The lumbar spine is a part of your back comprised of five bones called vertebrae. These bones help to provide mobility and stability to your back and spinal column and are an attachment point for many muscles and ligaments. Problems with the lumbar spine may cause pain and limited motion in your back or hips.


In a normal, healthy spine, the five lumbar vertebrae stack on top of one another in a centered alignment. While all vertebrae have approximately the same shape, the lumbar bones are the largest. This is because they carry a larger load transmitted from the top of the head down to the low spine.

Another reason why the lumbar bones are larger than the cervical and thoracic vertebrae is that they must be big and strong to support the muscles and bones during movement. The lumbar area of the spine is the physical center of the body. This area is the hub for many basic activities, including balance and the generation of locomotion (walking and running, etc.) The demands on the lumbar area are great.

Above and below each vertebra is an intervertebral disk. The disk serves as a shock absorber between each lumbar bone. The lumbar vertebrae and disks take the load coming down the spine, thereby supporting the body's weight.

The back of the vertebra is more complicated, with protrusions and valleys, each with a purpose integral to the spine. The bone extends out from the back of the vertebra to form canals for nerves, joints for stability, and attachment sites for muscles. Here is a list:

  • Spinous process
  • Transverse process
  • Facet joint
  • Lamina
  • Pedicle
  • Pars interarticularis

Each region of the spine has a directional curve associated with it. The normal curve of the lumbar spine is a lordosis. This is a forward curve that helps keep the discs and muscles in proper alignment. The lumbar spine rests upon the sacrum. The place where they meet is called the lumbosacral joint, or L5-S1.


One function of the lumbar spine is to protect lumbar nerve roots. These nerves travel from your spinal cord to your buttocks and legs. The lumbar bones create a canal where the nerves are protected.

The lumbar spine also serves as an attachment point for muscles. The latissimus, the iliospoas, and the paraspinals all attach at various points of the lumbar bones, helping to move them.

The lumbar spine also serves to help move the body. Motions of the lumbar spine include:

  • Flexion
  • Extension
  • Rotation
  • Sidebending

These movements are performed by the muscles attached in the low back, and may vary depending on strength and flexibility.


There are many conditions that may affect the lumbar spine. These may include:

These conditions may all result in loss of lumbar mobility, pain, and difficulty with sitting or standing tolerance.


Symptoms of Low Back Strain
 Verywell / Gary Ferster

If you have injured your lumbar spine, you may feel various symptoms, including, but not limited to:

  • Back pain
  • Hip, thigh, or leg pain
  • Loss of back mobility
  • Weakness in your back, hip, or leg
  • Numbness or tingling in your hip, thigh, or leg

If you have any of these symptoms, you should see a healthcare provider right away. They can diagnose your condition and get you the right treatment.

Treatment for lumbar spine problems usually involves a combination of stretching and strengthening exercises. These exercises may include:

Working with a chiropractor or physical therapist may be in order to ensure you do the right things for your spine. Your specialist can also show you how to maintain proper posture to help prevent future problems with your lumbar spine.

Most episodes of back pain resolve within a few weeks of onset. You can expect to be back to normal within a month or so. If your symptoms persist, you should check in with your healthcare provider; you may require other treatments such as injections or surgery for your lumbar spine.

Understanding the basic anatomy of the 5 lumbar bones that make up your low back can help you get the right treatment and care for your back.

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  • Putzer M, Ehrlich I, Rasmussen J, Gebbeken N, Dendorfer S. Sensitivity of lumbar spine loading to anatomical parameters. J Biomech. 2016;49(6):953-958.