Cervical Facet Dislocation

Each vertebra in the neck connects to its neighbours in three places: the disc at the front and the two facet joints at the back. The facet joints are like shingles on a roof, overlapping to allow smooth bending and turning while preventing excessive movement. When a strong flexion (forward-bending) force, often combined with rotation, overwhelms these joints, the upper facet can slide up and over the lower one and lock in front of it — a "jumped" or "perched" facet. This displaces the vertebra forward and can compress the spinal cord.

A unilateral dislocation affects the facet joint on one side, and typically produces a smaller forward shift; the neck is often held rotated. A bilateral dislocation affects both sides and produces a larger forward shift, with a correspondingly higher risk of spinal cord injury. The distinction matters for both the risk and the treatment, and is defined precisely on imaging.

Cervical facet dislocations result from high-energy injuries that force the neck into flexion, often with rotation — for example road traffic collisions, falls from height, and diving or sporting injuries. The same forces frequently tear the disc and the ligaments at the injured level, which is an important consideration in treatment.

Severe neck pain and a mechanically restricted, sometimes rotated, neck posture are usual. Because the spinal cord and nerve roots may be affected, there can be weakness, numbness or pins-and-needles in the arms or legs, and in severe cases signs of a significant spinal cord injury. A nerve root pinched at the dislocated level can cause pain, weakness or numbness in a specific part of the arm.

A cervical facet dislocation is a spinal emergency. After any high-energy neck injury, the neck must be kept still and the person assessed urgently. Weakness, numbness or pins-and-needles in the arms or legs, loss of bladder or bowel control, or difficulty breathing are all signs of possible spinal cord involvement and require immediate attention.

Imaging defines the injury. A CT scan shows the dislocated facets and the forward shift of the vertebra in detail. An MRI scan is especially important in facet dislocations because it shows the spinal cord and, crucially, whether a disc has been pushed backwards out of its space — information that directly affects how the injury should be realigned. The examination and imaging together determine the severity and guide treatment.

A central goal is to realign the joints and restore the normal position of the spine, relieving pressure on the cord. This "reduction" may be achieved by applying carefully controlled traction to the neck, or during surgery. An important and sometimes debated point is the role of an MRI scan before reduction: if a torn disc has moved behind the vertebra, realigning the bones without accounting for it can, in some circumstances, risk pushing the disc onto the cord. For this reason, in a person who cannot be examined (for example if unconscious), an MRI is often obtained first; in an awake, cooperative person, careful monitored reduction may be undertaken. The approach is judged case by case.

Because the disc and ligaments are usually torn, cervical facet dislocations almost always need surgery to stabilise the injured level after realignment; a collar alone is rarely sufficient. Surgery may be performed from the front of the neck, from the back, or from both, and the choice depends on factors such as whether a disc fragment needs to be removed and the severity of the ligament disruption. The aim is a realigned, decompressed and stable spine that allows safe rehabilitation.

The outlook depends heavily on whether the spinal cord was injured and how severely. Where the cord is spared and the spine is realigned and stabilised promptly, many people do well, though neck stiffness at the fused level is expected. Where there is a spinal cord injury, the outlook follows that of the cord injury itself, and rehabilitation is central. Early, appropriate treatment gives the best chance of a good result.

The most serious potential complication is spinal cord injury, either from the original trauma or, rarely, related to an unsafe reduction. Other issues include nerve root injury, failure of the spine to fuse, and the general risks of surgery. Careful use of imaging around the time of reduction is aimed at minimising the risk to the cord.

Myth: "A dislocation can just be popped back and treated in a collar." Fact: Because the disc and ligaments are usually torn, surgery to stabilise the spine is almost always needed after realignment.

Myth: "Realigning the neck is always safe to do straight away." Fact: A torn disc behind the vertebra can complicate reduction, which is why an MRI is often obtained first in certain patients.

Myth: "If the arms and legs work, the injury isn't serious." Fact: A facet dislocation is a serious, unstable injury even when the spinal cord is spared, and needs urgent stabilisation.

This page is for general education and does not replace an individual assessment. Treatment depends on a person's specific symptoms, examination findings, imaging findings and overall health, and should always be discussed with a suitably qualified healthcare professional.

The vertebrae of the neck are linked at the back by small paired joints called facet joints, which guide and limit movement. In a cervical facet dislocation, a violent force causes these joints to "jump" out of their normal position, so that the upper vertebra slides forward on the lower one. The dislocation may affect one side (unilateral) or both (bilateral). It is a serious injury: because the shift narrows the space for the spinal cord, facet dislocations — particularly bilateral ones — carry a significant risk of spinal cord injury. Treatment centres on realigning the joints and holding the neck stable, and modern practice pays close attention to the discs and ligaments, which are frequently torn. This page explains the injury, its assessment and its treatment.

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• —Vaccaro AR, Hulbert RJ, Patel AA, et al. The subaxial cervical spine injury classification system (SLIC): a novel approach to recognize the importance of morphology, neurology, and integrity of the disco-ligamentous complex. Spine (Phila Pa 1976). 2007;32(21):2365-2374. doi:10.1097/BRS.0b013e3181557b92
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• —National Institute for Health and Care Excellence (NICE). Spinal injury: assessment and initial management. NICE guideline NG41. 2016. https://www.nice.org.uk/guidance/ng41
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• —Guideline note (place near references): The Congress of Neurological Surgeons / AANS "Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries" (2013) and NICE NG41 were reviewed. AO Spine / SLIC subaxial classifications inform injury description. No stand-alone AAOS clinical practice guideline specific to cervical facet dislocation was identified at the time of writing.

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.