The L5-S1 intervertebral disc joint is classified as which type of joint?

The L5-S1 intervertebral disc joint is classified as which type of joint?

• A. Cartilaginous (non-synovial)
• B. Syndesmosis
• C. Slight movement
• D. Synovial

Answer: (A)

Think about what connects the bodies of adjacent vertebrae. The intervertebral disc is a pad of fibrocartilage (the annulus fibrosus around a nucleus pulposus) that sits between the vertebral endplates. There’s no joint capsule or synovial cavity here, so the joint between the vertebral bodies is a cartilaginous joint, specifically a fibrocartilaginous symphysis. This type is amphiarthrotic, allowing only limited movement, which fits how the lumbar spine moves overall. It isn’t a synovial joint, which would have a capsule and a joint cavity with synovial fluid, nor a syndesmosis, which is a fibrous connection between bones. The option describing "slight movement" refers to the amount of motion rather than the tissue type of the joint.

Think about what connects the bodies of adjacent vertebrae. The intervertebral disc is a pad of fibrocartilage (the annulus fibrosus around a nucleus pulposus) that sits between the vertebral endplates. There’s no joint capsule or synovial cavity here, so the joint between the vertebral bodies is a cartilaginous joint, specifically a fibrocartilaginous symphysis. This type is amphiarthrotic, allowing only limited movement, which fits how the lumbar spine moves overall.

It isn’t a synovial joint, which would have a capsule and a joint cavity with synovial fluid, nor a syndesmosis, which is a fibrous connection between bones. The option describing "slight movement" refers to the amount of motion rather than the tissue type of the joint.