Zygapophysial joint
A thoracic vertebra. (Superior labeled at top; inferior labeled at bottom.)
Median sagittal section of two lumbar vertebræ and their ligaments.
Latin	articulationes zygapophysiales
MeSH	zygapophyseal+joint

A zygapophysial joint (zygapophyseal, or facet 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 prevent rotation in the transverse plane, whilst allowing sagittal rotation (flexion and extension) and a small amount of frontal rotation (lateral bending). These functions can be disrupted by degeneration, dislocation, fracture, injury, instability from trauma, osteoarthritis, and surgery.

[edit] See also

• Articular processes
• Zygapophysis
• Artificial facet replacement

[edit] External links

• Atlas of anatomy at UMich back_bone28 - "Lumbar Vertebral Column, Posterolateral View"
• Diagram at spineuniverse.com
• Diagram at necksurgery.com

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v • d • e Joints and ligaments of torso (TA A03.02-04, GA 3.299) Vertebral column Syndesmosis articulations of vertebral bodies: anterior longitudinal ligament · posterior longitudinal ligament articulations of vertebral arches: ligamenta flava · supraspinous ligament (nuchal ligament) · interspinal ligament · intertransverse ligament Synchondrosis intervertebral disc (annulus fibrosus, nucleus pulposus) Synovial joint Atlanto-axial (lat + med) capsule · atlantoaxial ligaments (anterior, posterior) · Cruciate ligament of atlas (Transverse ligament of atlas) Alar ligament · Apical ligament of dens · Tectorial membrane of atlanto-axial joint Zygapophysial no ligaments Lumbosacral iliolumbar ligament Sacrococcygeal anterior sacrococcygeal ligament · posterior sacrococcygeal ligament Thorax Costovertebral articulation of head of rib: radiate ligament · interarticular ligament costotransverse: Lumbocostal ligament Sternocostal interarticular sternocostal ligament · radiate sternocostal ligaments · costoxiphoid ligaments Interchondral no ligaments Costochondral no ligaments Pelvis Syndesmoses of pelvic girdle Obturator membrane · Obturator canal Pubic symphysis superior pubic ligament · inferior pubic ligament Sacroiliac anterior sacroiliac ligament · posterior sacroiliac ligament · interosseous sacroiliac ligament ligaments connecting the sacrum and ischium: sacrotuberous ligament · sacrospinous ligament Greater sciatic foramen · Lesser sciatic foramen