Sent to attorneys Monday, August 17, 2026 at 1:10 PM CT.
Counsel,
A brief note on the facet joints, since much of what follows in this series turns on them. Every level of the spine stacks on the level below at three points: the intervertebral disc in front, and a pair of small facet joints in back. The facet joints are true synovial joints, meaning they have a smooth cartilage surface, a lubricated joint capsule, and a small amount of joint fluid, just like a knee or a hip on a much smaller scale. They sit at the back of each vertebra where two bony processes overlap and articulate.
Their job is mechanical. The discs handle compression from above; the facets handle guidance and constraint. They tell each spinal level how far it can bend, twist, and extend before the motion stops, and they carry a meaningful share of the load whenever the spine is extended backward or loaded off-center. That load-sharing role is why facet pain often flares with prolonged standing, walking downhill, lying prone, or reaching overhead. All of those postures load the facets, not the discs.
The joint capsule itself is richly innervated by small pain nerves called medial branches, one from the level of the joint and one from the level above. That dual innervation is what makes each facet joint capable of generating pain on its own, and it is also what determines the diagnostic and treatment approach that will come up in the notes to follow. When a facet is inflamed, torn, arthritic, or capsularly stretched by a hyperextension or whiplash-type injury, the pain is typically axial (neck or low back rather than radiating down a limb), one-sided or asymmetric, worse with extension, and often referred into predictable patterns: into the shoulder blade or upper arm from the cervical facets, into the buttock or upper thigh from the lumbar facets. These referral patterns are not radiculopathy; they follow the sclerotome (the deep somatic pattern of a joint), not a dermatome, which is why they stop short of the hand or foot.
Two practical points for records review. First, a normal MRI does not rule out a facet-mediated injury. Facet capsular tears and inflammation are frequently invisible on standard MRI sequences, and the diagnosis is usually made physiologically with a medial branch block rather than radiographically. Second, when a patient has axial neck or low-back pain that worsens with extension after a rear-end collision, a fall, or a lifting injury, the facets belong on the working differential from the start, not after everything else has been ruled out.
I hope you found this interesting.
Questions or comments about today’s educational update, or a topic you would like us to address in a future edition? Contact us through our website: OrthOpinions
F. Allen Johnston, MD
Louisiana Orthopedic Institute
Baton Rouge
(225) 751-6666 Office
(225) 270-0000 Cell
See also the hub article: Facet joint pain: diagnosis, conservative care, medial branch blocks, and radiofrequency ablation.
