
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 especially true in the lumbar spine. The facet joints, both superior and inferior, are aligned in a way to allow flexion and extension, and to limit rotation.
Articular pillar lumbar spine manual#
Cavitation of the synovial fluid within the facet joints is responsible for the popping sound ( crepitus) associated with manual spinal manipulation, commonly referred to as "cracking the back." In the thoracic spine the facet joints function to restrain the amount of flexion and anterior translation of the corresponding vertebral segment and function to facilitate rotation. These functions can be disrupted by degeneration, dislocation, fracture, injury, instability from trauma, osteoarthritis, and surgery. Facet joints appear to have little influence on the range of side bending (lateral flexion). In the lumbar spine, for example, the facet joints function to protect the motion segment from anterior shear forces, excessive rotation and flexion. The biomechanical function of each pair of facet joints is to guide and limit movement of the spinal motion segment. In this case, there is no L5 medial branch to innervate the facet joint. However, the L5 and S1 facet joint is innervated by the L4 medial branch nerve and the L5 dorsal ramus. Facet joint between L1 and L2 the T12 and L1 medial branch nerves. For example, the facet joint between T1 and T2 is innervated by C8 and T1 medial branch nerves. In the thoracic and lumbar spine, the facet joints are innervated by the medial branch nerves from the vertebral segment above the upper segment and the upper segment.

Innervation to the facet joints vary between segments of the spinal, but they are generally innervated by medial branch nerves that come off the dorsal rami. There are two facet joints in each spinal motion segment and each facet joint is innervated by the recurrent meningeal nerves. The facet joints (or zygapophysial joints, zygapophyseal, apophyseal, or Z-joints) are a set of synovial, plane joints between the articular processes of two adjacent vertebrae. Illustration highlighting facet joint articulation between two vertebrae
