What are facet joints and their main function?

Facet joints, also known as zygapophyseal or apophyseal joints, are small synovial joints located between the articular processes of adjacent vertebrae in the spinal column. Their primary function is to connect these adjacent vertebrae, which allows for controlled movement and stability of the spine. These joints play a crucial role in enabling flexion, extension, rotation, and lateral bending of the vertebral column.

By facilitating movement between the vertebrae, facet joints help to maintain spinal alignment and contribute to the overall flexibility of the spine. They also help to limit certain movements to prevent excessive or abnormal motion, which can lead to injury. This joint system is essential for maintaining mobility and providing support to the spinal structure during various activities.

The other choices, while related to spinal function, do not accurately describe the primary role of facet joints. For example, while the spine does indeed support spinal nerves and absorb shock during movement, these functions are mainly associated with other structures like intervertebral discs and the overall spinal column, rather than the facet joints specifically.