A pre-patellar bursa is a space between the tissues in front of the knee which is enclosed like an envelope and lined with lubricating cells.
![pre-patellar-bursa](/sites/default/files/users/user1/pre-patellar-bursa.png)
This is an illustration of the inside of the knee from a side view as if it was cut through the middle. You can see that there are several bursae around the knee. The pre-patellar bursa is just in front of the kneecap.
Function of the pre-patellar bursa
As the knee bends and straightens with ordinary activities, the bursae - being lubricated - allow the tissues to slide and accommodate the activity. When a bursa becomes inflamed, perhaps from impact or involvement in repeated movement, it may fill with fluid and become painful, and range of motion of the knee may be reduced.
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