endplate

An endplate is a thin plate of tissue that forms the interface between two structures in the body. In human anatomy the term is most commonly applied to the vertebral endplate, the boundary between a vertebral body and the adjacent intervertebral disc. Endplates may consist of a cartilaginous component and a bony component that together connect the disc to the vertebra.

In the spine, the vertebral endplate comprises a thin layer of hyaline cartilage that overlays the subchondral bone of the vertebral body and is continuous with the disc’s outer ring, the annulus fibrosus. Beneath the cartilage lies the bony endplate, which provides a rigid interface to the underlying vertebral trabecular bone. The endplate is typically thin and semipermeable, playing a key role in nutrient diffusion from the vascularized subchondral bone to the avascular intervertebral disc.

Functionally, endplates distribute axial loads from the disc to the vertebral body and help anchor the disc to the bone. They also regulate the exchange of nutrients, metabolites, and signaling molecules between the vertebral body and the disc, contributing to disc health and longevity. The integrity of the endplate influences susceptibility to degeneration and certain spinal pathologies.

Clinically, endplate damage or degeneration is associated with intervertebral disc disease and may manifest as Modic changes on MRI. Defects in the endplate can permit herniation of nucleus pulposus into the vertebral body, producing Schmorl’s nodes. Endplate pathology is thus considered an important factor in spinal degeneration and pain.