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Understanding Facet Joint Injections

Facet joint injections are a treatment option for back pain but may also be used by a doctor to help diagnose the source of back pain. Injections can be done in a doctor’s office, surgery center or as an outpatient procedure in a hospital. To better understand facet injections we should first understand where the facet joints are located and their purpose.

Where is the Facet Joint?

The facet joint, also known as the zygapophysial joint or z-joint, is located in the back of the spinal column between two adjacent vertabrae. There are two facet joints between each set of vertabrae, one of the left side and one on the right.

The facet joints help stabilize the spine while allowing it to bend and twist.

where is the facet joint? what are facet joint injections?

Source: Wikipedia 1

See Also: Spine Anatomy

The joints’ cartilage and synovial fluid help allow for smooth motion and prevent the bones from rubbing together. However, like other areas of the spine, facet joints can degenerate and/or become arthritic as part of the normal aging process.

What are Facet Joint Injections?

A facet joint injection, also known as a facet block, is when a small amount of anesthetic (numbing agent) and/or steroid (anti-inflammatory) are injected directly into the facet joint.2

If you experience back pain a doctor may recommend facet joint injections for two reasons:

  1. Diagnosis
    • If pain is eliminated after a facet joint injection then, most likely, the facet joint was the source of the pain. If the patient experiences little to no pain relief then the source of the pain is probably elsewhere.
  2. Treatment (Pain Relief)
    • The numbing and anti-inflammatory effects of a facet injection can help reduce back pain.

How Long do Facet Joint Injections Last?

The pain relieving effect of a facet joint injection can vary from patient to patient.

If a steroid is used it may take 2-7 days to start taking effect. The effect of the steroid may be felt for weeks or months, depending on the patient.3,4  In some cases, a doctor may ask you to keep a pain journal after the facet injection to help them better understand the cause of your pain and determine the best treatment path.


  1. Wikipedia
  2. Spine-Health
  3. Portland Pain Care
  4. MedCentral
*Please Note: Information on this site or any recommended sites should not be used as a diagnosis or a substitute for talking with your doctor. Always talk with your doctor about diagnosis and treatment information.
Blue Distinction Center for Spine Surgery