What is the inner gel-like core of the disc called?

• A. Spinal canal
• B. Vertebral body
• C. Nucleus pulposus
• D. Annulus fibrosus

Answer: (C)

The inner gel-like core of an intervertebral disc is called the nucleus pulposus. This central, jelly-like material is rich in water and proteoglycans, which lets it deform under pressure and evenly distribute loads, helping the disc absorb shocks during movement. The outer fibrous ring surrounding it is the annulus fibrosus, which keeps the nucleus contained. By contrast, the spinal canal is the passage within the vertebral column for the spinal cord, and the vertebral body is the bony front part of a vertebra. This distinction helps explain why changes in the nucleus pulposus, such as degeneration or herniation, can impact surrounding nerves.