Subcutaneous prepatellar bursa

The subcutaneous prepatellar bursa is an extra-articular sac located anterior to the patella, functioning to reduce friction between the skin and the patella. Anatomically, it is most commonly a trilaminar structure, as demonstrated in cadaveric studies. The mean dimensions of the prepatellar bursa are approximately 39.7 mm in the craniocaudal plane, 40.5 mm in the lateromedial plane, and 3.2 mm in the anteroposterior plane.[1]

The bursa typically consists of three potential bursal spaces, which are separated by fibrous layers. These layers include a superficial transversely oriented fascia, an intermediate obliquely oriented aponeurosis, and a deep layer of longitudinally oriented fibers of the rectus femoris tendon.[2] This trilaminar arrangement was observed in 93% of the dissected knees in one study, with variations in the presence of the intermediate layer in a small percentage of cases.[2]

Histopathologic analysis has confirmed the presence of these three potential bursal spaces, which can become inflamed and distended due to various pathological processes.[1] Understanding the detailed anatomy of the prepatellar bursa is crucial for accurate diagnosis and management of prepatellar bursitis and other related conditions.