The joint capsule of the femoropatellar joint is one the three sacs constituting the joint capsule of the stifle joint, others being the lateral and medial sacs of the femorotibial joint.
In dogs, the patellar part of the joint capsule of stifle joint is much more capacious than the lateral and medial femorotibial sacs.
The joint capsule attaches to the edges of the patella and adjacent to the patella, the parapatellar fibrocartilages develop in the fibrosa of this joint capsule. Proximally a sac of the femoropatellar joint capsule protrude 1,5 cm deep to the dont of the quadriceps femoris muscle.
Distal to the patella, the fibrous layer of the joint capsule of the femorpatellar joint contains a large quantity of fat termed the infrapatellar fat body, wich increases in thickness distally.