The structure indicated is the prepatellar bursa of the knee joint.
The synovial membrane of the knee joint forms bursae to protect the structures of the knee joint and to provide low friction surfaces to allow tendons and structures of the knee joint to glide smoothly over one another. In addition there are several other bursae which do not communicate with the joint cavity, located in and around the knee joint. The prepatellar bursa is found anteriorly, and as the name suggests, in front of the patella. There are several other bursae located laterally and medially.
- Suprapatellar bursa
- Prepatellar bursa
- Infrapatellar bursa (superficial and deep bursae)
- Pretibial bursa
The prepatellar bursa can become inflamed, causing swelling and pain above the kneecap. Prepatellar bursitis also known as housemaid’s knee, as it is commonly found in people who frequently kneel, causing pressure and friction on the prepatellar bursa.
Learn more about the anatomy of the knee joint in this anatomy tutorial
Explore the knee joint with our 3D anatomy atlas