Zygapophysial joint

Zygapophysial joint

A thoracic vertebra. The zygapophysial joint is the joint between the superior articular process (labeled at top) and the inferior articular process (labeled at bottom)

Median sagittal section of two lumbar vertebrae and their ligaments
Details
Latin Articulationes zygapophysiales
Identifiers
MeSH A02.835.583.979
Dorlands
/Elsevier		 a_64/12161688
TA A03.2.06.001
FMA 71382
Anatomical terminology
Illustration highlighting facet joint articulation between two vertebrae

The zygapophysial joints (zygapophyseal, apophyseal, Z-joints, or facet joints) are a set of synovial, plane joints between the articular processes of two adjacent vertebrae. 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.

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 zygapophysial joint in particular. This is commonly known as facet joint arthritis 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 pain 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.

Treatment

Illustration depicting facet joint block

Conservative treatment of facet joint arthritis involves chiropractic, physical therapy, or osteopathic medicine with correction of posture and biomechanics being the key. Acupuncture and Chinese medicine can provide pain relief as well as increasing blood flow to the tissues to promote healing. More advanced cases involving severe inflammatory response in the Z-joint, not unlike a swollen arthritic knee. Steroid injections may provide temporary pain relief. This is typically performed under image guidance to ensure accuracy given the complex shape and deep location of the facet.[1]

Etymology

Ancient Greek: zygon ("yoke") + apo ("out/from") + phyein ("grow")

See also

References

  1. ↑ NASS on facet joint injections

External links