The spine is made up of bones called vertebrae. Each vertebra has two pairs of facet joints. One pair points up and connects with the vertebrae above. The second pair points down and connects with the vertebrae below.

These joints have cartilage, ligaments, and a surrounding sac of fluid to allow smooth movement. Injury to any of these structures may cause swelling and pain. The swelling may also put pressure on nerves as they exit the spinal cord. This may result in local pain or pain that shoots down the limbs.

A facet joint injection is a shot directly into the joint. The shot will have a small amount of a numbing medicine (anesthetic) and/or medicine to reduce swelling.

In some cases, the injection is done just beside the joint at a tiny nerve branch that supplies the joint. This is called a medial branch block. This is often done as a diagnostic test with just a numbing medicine to see if the targeted area is the source of pain.

Facet Joint Injection
facet joint injection
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It is not always clear what causes back or neck pain. It may be caused by problems of the joint, nerves, or other structure, such as muscles or ligaments. A facet joint injection of a numbing medicine may be used to confirm or disprove the joint as the cause of pain.

If the facet joint is the cause of pain, injections may be used to deliver steroid medicine to try to help control pain and inflammation.