Articular Cartilage
The smooth, white tissue covering the ends of bones in joints. Its breakdown is the primary feature of osteoarthritis.
Extended Definition
Articular cartilage (also called hyaline cartilage) is a specialized connective tissue that covers the bone surfaces within synovial joints. It provides a smooth, low-friction surface for movement and helps distribute loads across the joint.
Unique Properties
- No blood vessels - Relies on synovial fluid for nutrients
- No nerves - Cartilage damage itself doesn’t cause pain (but exposed bone does)
- Limited healing capacity - Cannot regenerate once damaged
- 95% water - In healthy cartilage, giving it resilience
Thickness Varies by Joint
- Knee (femur) - Up to 7mm thick
- Hip - 1-3mm thick
- Ankle - 1-2mm thick
The Osteoarthritis Connection
OA begins with articular cartilage damage:
- Surface becomes rough and fibrillated
- Thickness decreases over time
- Eventually exposes underlying bone
- “Bone-on-bone” contact causes pain
Hyaluronic acid injections help by lubricating what cartilage remains, reducing friction and potentially slowing further damage.
Related Terms
More Anatomy Terms
View allAcetabulum
The cup-shaped socket of the pelvis that holds the head of the femur (thigh bone) in the hip joint.
Bursae
Small, fluid-filled sacs that act as cushions between bones, tendons, and muscles near joints, reducing friction during movement. Singular form is 'bursa.'
Bursa
Small, fluid-filled sacs that cushion bones, tendons, and muscles near joints. Bursitis (inflammation of a bursa) can cause joint pain similar to arthritis.
Cartilage
A smooth, rubbery connective tissue that covers and protects the ends of bones where they meet to form joints, allowing them to glide smoothly during movement.
Femur
The thigh bone - the longest and strongest bone in the body. The lower end of the femur forms the upper part of the knee joint.