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.
Extended Definition
Bursae (plural) are found throughout the body, particularly around major joints. They reduce friction between moving structures and allow smooth gliding of tendons and muscles over bone.
Common Bursae Locations
Knee:
- Prepatellar (in front of kneecap)
- Infrapatellar (below kneecap)
- Pes anserine (inner knee)
Hip:
- Trochanteric (outer hip)
- Iliopsoas (front of hip)
Shoulder:
- Subacromial (under rotator cuff)
Bursitis vs. Arthritis
| Feature | Bursitis | Arthritis |
|---|---|---|
| Location | Outside joint | Inside joint |
| Onset | Often sudden | Usually gradual |
| Cause | Overuse, pressure | Wear, inflammation |
| Treatment | Rest, cortisone | Multiple options |
Why It Matters
Bursitis can mimic arthritis pain, making accurate diagnosis important. Treatment approaches differ—bursitis often responds well to cortisone, while OA may benefit more from HA injections.
Treatment Note
HA injections are given INTO the joint, not into bursae. Bursitis is typically treated with corticosteroid injections directly into the affected bursa.
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.
Articular Cartilage
The smooth, white tissue covering the ends of bones in joints. Its breakdown is the primary feature of osteoarthritis.
Bursae
Small, fluid-filled sacs that act as cushions between bones, tendons, and muscles near joints, reducing friction during movement. Singular form is 'bursa.'
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.