Suprapatellar bursa

The suprapatellar bursa is located in the proximal deep layer of the patella between the quadriceps tendon and the anterior surface of the femur, extending superiorly from the patella.

It is typically in communication with the knee joint cavity in 85 % of people, and may be called as suprapatellar recess of articular cavity of knee joint, although this communication can be influenced by the presence and type of the suprapatellar septum.

It functions to reduce friction between the quadriceps tendon and the femur.

The suprapatellar septum can vary anatomically, with four main types identified: a complete septum, a perforated septum, a residual septum, and an extinct septum. The type of septum present determines the degree of communication between the suprapatellar bursa and the knee joint cavity.[1-2] Additionally, the suprapatellar bursa can change from a single-membrane to a double-membrane structure during knee joint extension, which may play a role in limiting knee joint range of motion and contributing to pain at approximately 90 degrees of flexion.[3]

The articularis genus muscle, which is closely associated with the anterior aspect of the knee joint, may also influence the dynamics of the suprapatellar bursa by elevating or retracting it during knee movements.[4] Understanding the anatomy and variations of the suprapatellar bursa is crucial for diagnosing and managing conditions such as suprapatellar bursitis and other pathologies affecting this region.