The suprapatellar bursa refers to the expansion of the joint capsule at the upper edge of the patella, which is one of the components of the joint capsule and communicates with the joint cavity. The clinical significance of the suprapatellar bursa is as follows: 1. To determine whether the joint is swollen: if there is a large amount of fluid in the joint, the fluid will mainly accumulate at the suprapatellar bursa, which will cause patellar fullness and patellar floatation; 2. As an ideal part of the joint cavity for injections: because the joint of the suprapatellar bursa can also be directly communicated with the medial and lateral spaces of the knee joint, the medication injections can be performed to flow all the way from the suprapatellar bursa into the joint cavity.