Bursae are lubricating mechanisms which are provided at sites of friction to smoothen movement. Undue pressure on them may cause their pathological enlargement. Bursae present in relation to the patella are described here.

Prepatellar Bursa

It lies in front of the lower part of the patella and of the upper part of the ligamentum patellae. Chronic enlargement of this bursa is known as Housemaid’s knee because it commonly occurs in housemaids of western countries who kneel for cleaning floors. Infection of this bursa is common in miners (miner’s beat knee).

Subcutaneous Infrapatellar Bursa

It lies in front of lower part of the tibial tuberosity and of the lower part of the ligamentum patellae. It Is sometimes enlarged in clergymen and the condition is known as clergyman’s knee. A clergyman is a Christian priest who often kneels down during prayer.