Knee Bursa

Knee bursa are small fluid filled sacs which contain synovial fluid.  They sit between 2 surfaces, usually muscle and bone, to reduce friction, a bit like ball bearings. This allows everything to move smoothly preventing inflammation.

Bursae are found all over the body and there are approximately fourteen knee bursa.

Sometimes the bursa get damaged, known as bursitis, which can cause pain. This is usually when there is excessive friction over the bursa causing it to either become inflamed, or when it dries out so it no longer works properly.

The Main Knee Bursae

We will start by looking at the five main bursa that work to protect the knee. They are:

The locations of the knee bursa

1) Prepatellar Bursa

This is found in front of the kneecap. Inflammation of this occurs when there is repeated friction over the kneecap, such as with prolonged forward kneeling. This is known as Housemaids Knee but today is more common in trades such as roofers and carpet fitters.

2) Infrapatellar Bursa

There are actually two infrapatellar bursa both found underneath the kneecap protecting the patellar tendon. They are known as the deep and superficial infrapatellar bursa.  Inflammation of these is known as Clergyman's Knee and is usually caused by more erect kneeling than with prepatellar bursitis.

3) Suprapatellar bursa

This is found above the kneecap underneath the quadriceps tendon at the bottom of the thigh preventing friction from the femur.

4) Pes Anserine Bursa

This is found on the inner side of the knee approximately two inches below the joint between the tendons of the sartorius, gracilis and semitendinosis muscles and the medial collateral ligament. Inflammation of Pes Anserine is especially common in runners.

Inflammation of the semimembranosus knee bursa is known as a Bakers Cyst

5) Semimembranosus Bursa

This is found at the back of the knee between the semimembranosus muscle (one of the hamstring muscles) and the medial head of gastrocnemius (one of the calf muscles). Inflammation of this is known as a Bakers Cyst which often forms a small lump like a squashy orange.  It often develops with knee arthritis

Other Knee Bursa

The other bursa knee locations are:

Anteriorly (front of the knee): pretibial and deep infrapatellar bursa

Medially (inner side): medial gastrocnemius bursa, the bursa between semitendinosus tendon and the head of the tibia and occasionally there is a bursa between the tendons of semimembranosus and semitendinosus

Laterally (outer side): lateral gastrocnemius, fibular, fibulopopliteal and the subpopliteal bursae

Possible Problems

Problems usually develop in the bursa when there is muscle tightness or weakness which causes excessive friction on the bursa. The knee bursa can become either:

Inflammation of the prepatellar knee bursa

1) Inflamed: i.e. swollen known as bursitis or
2) Dried out: i.e. they lose the fluid inside them

This results in more friction on the bone and muscles/tendons leading to bursa knee pain. Usually a combination of strengthening and stretching exercises, medication and injections helps them to recover. 

What Next?

To find out more about what can go wrong with the knee bursa, visit the bursitis of the knee section to find out more about prevention and bursitis treatment.

To find out more about this different structures in the knee, including the muscles, ligaments and cartilage, visit the anatomy section.

Alternatively, if you have a problem with your knee and would like help working out what is causing it, visit the knee pain diagnosis section.

Go to Anatomy Guide or Homepage


Your Comments

Share your knee pain experiences with others, whether it be ideas, top tips, things that worked well for you, problems you've had etc.......

© knee-pain-explained.com 2010-2015
Last updated 27th January 2015
Knee-Pain-Explained.com is a trading name of Wilson Health Ltd
All rights reserved. Terms & Conditions apply

Protected by Copyscape Online Copyright Search

The material on this website is intended for educational information purposes only.  It should not substitute or delay medical advice, diagnosis or treatment.


KneePainExp

See Also

Anatomy Guide

How can I strengthen my leg?

Test your flexibility - would stretching help you?

What is causing my knee pain?



Search This Site


Visitor Comments

“This is one of the best self-help & info sites of any medical condition I've ever seen. Excellent work.” Amy, UK

"Your site and exercises have been a lifesaver! The explanations are so clear.  Thanks for your help and excellent work."  Claire, US

"I'm an RN. This is really useful, easy to understand info."
Jan, US

“Thanks to KPE.com. Lots of improvement after just two days.” Suresh, India

"This is the best self-help site I have ever seen for knee pain. It is very difficult to find such a comprehensive volume of information on one site without being advised to "Just purchase this product!" Many, many thanks" Jennifer, US

"Superb site, many thanks, so much helpful content especially the targeted strengthening exercises for me.” Gerri, UK

“Thank you so much, your response makes so much sense. Thank you again for your time in answering my questions.” Cynthia, US

"Your website is a gold mine, thank you very much."
Gavril, Denmark

"I LOVE your website. Out of all the others, yours is so informational and easy to read." Michelle, US

"This is the best site dealing with knee problems that I have come across. I will be putting the stretches and exercises into practise. Thank you!"
Margaret, S. Africa