Intervertebral discs are crucial components of the spinal column, sitting between the vertebrae. They are flat, round, and about a half-inch thick, composed of two main parts: the Nucleus Pulposus and the Annulus Fibrosus. The Nucleus Pulposus, a jelly-like center made partly of water, provides flexibility and strength to the disc. The Annulus Fibrosus surrounds the Nucleus Pulposus, adding structural integrity. These discs serve as amphiarthrosis joints, allowing limited movement between vertebrae and functioning as a type of cartilaginous symphysis joint.
Each intervertebral disc, a fibrocartilaginous pad, fills the gap between adjacent vertebral bodies and is anchored to them, ensuring strong unity and providing necessary padding during weight-bearing activities. They are essential for maintaining spinal cord movement while keeping it connected and intact. Intervertebral discs are primarily responsible for absorbing compression stresses and shocks.
Intervertebral disc disease (IVDD) occurs when these discs degenerate, lose water content, calcify, and either rupture or protrude. This can lead to significant spine issues, including back pain in dogs, particularly in older or predisposed breeds. IVDD’s severity and type can vary, ranging from mild discomfort to paralysis.
In their functioning, intervertebral discs act somewhat like ball bearings, facilitating pivoting and movement while resisting loads. They are flexible under low loads but increase resistance at high loads. Notably, these discs lack blood or nerve supplies, which is significant in their functioning and response to injury.
For more information on the anatomy of the spine, visit Virginia University’s Anatomy of the Spine. To understand the classification of joints, including cartilaginous joints, see Classification of Joints. For a detailed overview of the vertebral column, explore The Vertebral Column. Additionally, you can learn more about intervertebral disc anatomy at Disc Anatomy and about intervertebral disc disease in dogs at Canine Health Information.
