Postzygapophyses

Postzygapophyses are paired bony projections on the vertebra that form the inferior articular processes of the vertebra. They carry articular facets that connect with the corresponding superior articular facets of the adjacent vertebra, together with the prezygapophyses creating the zygapophysial joints that link successive vertebrae.

In most vertebrates, the postzygapophyses are located on the posterior portion of the neural arch and contribute to the articulation between neighboring vertebrae. The shape, size, and orientation of these processes vary among species and vertebral regions, reflecting different functional demands on flexibility and stability.

The primary role of postzygapophyses is to stabilize the spinal column by restricting excessive motion between vertebrae. By forming articulate joints with the prezygapophyses of the adjacent vertebra, they limit movements such as excessive flexion, extension, and, in some taxa, lateral tilting. This arrangement helps maintain alignment of the spine during locomotion and weight bearing.

In paleontology and comparative anatomy, postzygapophyses, along with prezygapophyses, are important diagnostic features for identifying vertebral elements and for inferring the range of motion and posture of extinct and extant reptiles, amphibians, and mammals. The term derives from the broader concept of zygapophyses, which describe the paired articular processes that balance articulation and stability across the vertebral column.