[citation needed] The biomechanical function of each pair of facet joints is to guide and limit movement of the spinal motion segment.

[1][2] In the lumbar spine, for example, the facet joints function to protect the motion segment from anterior shear forces, excessive rotation and flexion.

Cavitation of the synovial fluid within the facet joints is responsible for the popping sound (crepitus) associated with manual spinal manipulation, commonly referred to as "cracking the back."

In large part due to the mechanical nature of their function, all joints undergo degenerative changes with the wear and tear of age.

The location of facet joints, deep in the back and covered with large tracts of paraspinal muscles, further complicate the diagnostic approach.

Conservative treatment of facet joint arthritis involves physical therapy or osteopathic medicine, with muscle strengthening, correction of posture, and biomechanics being the key.

[7] Steroid injections are typically performed under image guidance to ensure accuracy given the complex shape and deep location of the facet.

[9] Current guidelines as per the International Spine Intervention Society require two successful medial branch blocks before progressing to a radiofrequency ablation.

Single-photon emission computed tomography/computed tomography (hybrid imaging) in the diagnosis of unilateral facet joint arthritis after internal fixation for atlas fracture.