Zygapophysial joint
Encyclopedia
A zygapophysial joint is a synovial joint
between the superior articular process
of one vertebra and the inferior articular process of the vertebra directly above it. There are two facet joints in each spinal motion segment
.
The biomechanical function of each pair of facet joints is to guide and limit movement of the spinal motion segment. In the lumbar spine, for example, the zygapophysial joints function to protect the motion segment from anterior shear forces, excessive rotation and flexion. Zygapophyseal joints appear to have little influence on the range of side bending (lateral flexion). These functions can be disrupted by degeneration, dislocation, fracture, injury, instability from trauma, osteoarthritis
, and surgery.
In the thoracic spine the zygapophysial joints function to restrain the amount of flexion and anterior translation of the corresponding vertebral segment and function to facilitate rotation.
or facet arthropathy.
patterns.
The location of facet joints, deep in the back and covered with large tracts of paraspinal muscles, further complicate the diagnostic approach. Typically facet joint arthritis is diagnosed with specialized physical examination
by specialist physicians. Advanced imaging such as MRI or CT may be necessary to confirm the diagnosis and to rule out other conditions.
, with correction of posture
and biomechanics being the key. More advanced cases involving severe inflammatory response in the Z-joint, not unlike a swollen arthritic knee
. Steroid injections may provide pain relief. This is typically performed under image guidance
to ensure accuracy given the complex shape and deep location of the facet.
Synovial joint
A Synovial joint, also known as a diarthrosis, is the most common and most movable type of joint in the body of a mammal. As with most other joints, synovial joints achieve movement at the point of contact of the articulating bones....
between the superior articular process
Articular processes
The articular processes or zygapophyses of a vertebra, two superior and two inferior, spring from the junctions of the pedicles and laminæ...
of one vertebra and the inferior articular process of the vertebra directly above it. There are two facet joints in each spinal motion segment
Functional spinal unit
A functional spinal unit is the smallest physiological motion unit of the spine to exhibit biomechanical characteristics similar to those of the entire spine....
.
The biomechanical function of each pair of facet joints is to guide and limit movement of the spinal motion segment. In the lumbar spine, for example, the zygapophysial joints function to protect the motion segment from anterior shear forces, excessive rotation and flexion. Zygapophyseal joints appear to have little influence on the range of side bending (lateral flexion). These functions can be disrupted by degeneration, dislocation, fracture, injury, instability from trauma, osteoarthritis
Osteoarthritis
Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...
, and surgery.
In the thoracic spine the zygapophysial joints function to restrain the amount of flexion and anterior translation of the corresponding vertebral segment and function to facilitate rotation.
Facet joint arthritis
In large part due to the mechanical nature of their function, all joints undergo degenerative changes with the wear and tear of age. This is particularly true for joints in the spine, and the zygopophysial joint in particular. This is commonly known as facet joint arthritisFacet syndrome
Facet syndrome is when the zygapophysial joints cause back pain. 55% of facet syndrome cases occur in cervical vertebrae, and 31% in lumbar. Facet syndrome can progress to spinal osteoarthritis, which is known as spondylosis...
or facet arthropathy.
Diagnosis
Facet joint arthritis often manifests as a dull ache across the back. However like many deep organs of the body it can be experienced by the patient in a variety of referral painReferred pain
Referred pain is pain perceived at a location other than the site of the painful stimulus. An example is the case of ischemia brought on by a myocardial infarction , where pain is often felt in the neck, shoulders, and back rather than in the chest, the site of the injury...
patterns.
The location of facet joints, deep in the back and covered with large tracts of paraspinal muscles, further complicate the diagnostic approach. Typically facet joint arthritis is diagnosed with specialized physical examination
Physical examination
Physical examination or clinical examination is the process by which a doctor investigates the body of a patient for signs of disease. It generally follows the taking of the medical history — an account of the symptoms as experienced by the patient...
by specialist physicians. Advanced imaging such as MRI or CT may be necessary to confirm the diagnosis and to rule out other conditions.
Treatment
Conservative treatment of facet joint arthritis involves physical therapyPhysical therapy
Physical therapy , often abbreviated PT, is a health care profession. Physical therapy is concerned with identifying and maximizing quality of life and movement potential within the spheres of promotion, prevention, diagnosis, treatment/intervention,and rehabilitation...
, with correction of posture
Neutral spine
A neutral spine or good posture refers to the "three natural curves [that] are present in a healthy spine."- Posture :The word "posture" comes from the Latin verb "ponere" which is defined as "to put or place." The general concept of human posture refers to "the carriage of the body as a whole, the...
and biomechanics being the key. More advanced cases involving severe inflammatory response in the Z-joint, not unlike a swollen arthritic knee
Knee arthritis
Arthritis is inflammation in the joints or area of the body where two bones come together. Joints are responsible for the movement of body parts. It is a condition that can be experienced all over the body or in a specific area...
. Steroid injections may provide pain relief. This is typically performed under image guidance
Fluoroscopy
Fluoroscopy is an imaging technique commonly used by physicians to obtain real-time moving images of the internal structures of a patient through the use of a fluoroscope. In its simplest form, a fluoroscope consists of an X-ray source and fluorescent screen between which a patient is placed...
to ensure accuracy given the complex shape and deep location of the facet.
See also
- Articular processesArticular processesThe articular processes or zygapophyses of a vertebra, two superior and two inferior, spring from the junctions of the pedicles and laminæ...
- Zygapophysis
- Artificial facet replacementArtificial facet replacementAn artificial facet replacement is a joint prosthesis intended to replace the natural facets by restoring normal motion while providing stabilization of spinal segments...
- Facet joint injectionFacet joint injectionFacet joint injections are used to alleviate symptoms of facet joint syndrome.The procedure typically takes 15–20 minutes, and usually uses local anesthetic. Using modern X-ray technology, multiple x-ray snapshots are taken during the procedure to ensure that the needle and injected agents are...
- Facet syndromeFacet syndromeFacet syndrome is when the zygapophysial joints cause back pain. 55% of facet syndrome cases occur in cervical vertebrae, and 31% in lumbar. Facet syndrome can progress to spinal osteoarthritis, which is known as spondylosis...
