The suprapatellar pouch (suprapatellar recess) is the extension of the knee joint cavity above the patella (kneecap).

Page updated January 2024 by Dr Sheila Strover (Clinical Editor)

suprapatellar pouch filled with fluid

 

This illustration shows the joint cavity filled with fluid, and it gives an idea of how large the joint space is. Generally it is all one big space, with the suprapatellar pouch being the upper part.

suprapatellar pouch

 

Here the knee is cut through the middle. The cavity of the joint is shown in dark grey. You can see that it extends above (suprapatellar), behind and below the patella.

 

What does 'suprapatellar' mean?

The word 'suprapatellar' means 'above the kneecap'. The suprapatellar pouch is the big cavity extending up from the joint cavity behind the quadriceps tendon and muscle. In this illustration it communicates with the rest of the joint cavity, but sometimes a membrane separates it into its own space, which can puzzle the novice arthroscopic surgeon.

  • Quote from a peer-reviewed paper:

    "The suprapatellar bursa is located between the quadriceps tendon and the femur. Failure of regression of the transverse septum formed in embryonic life between the suprapatellar plica and the knee joint fluid leads to the formation of this bursa."

    Citation: Chatra PS. Bursae around the knee joints. Indian J Radiol Imaging. 2012 Jan;22(1):27-30. doi: 10.4103/0971-3026.95400. PMID: 22623812; PMCID: PMC3354353.

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What is the significance of the suprapatellar pouch?

The interior of the pouch or bursa is lined with a slippery tissue (synovium), the cells of which secrete the joint fluid which lubricates the cavity, and allows the easy movement of all the structures during knee movement.

If there is too much joint fluid, then the whole pouch can swell up alarmingly like a balloon, and as the fluid is reabsorbed it can lead to the formation of sticky adhesions, which cause the knee to feel stiff, and these can organise into scar tissue, locking the walls of the pouch together and severely limiting movement of the knee.

Mostly, however, the value of the pouch to the surgeon is that clear fluid can be introduced under pressure during arthroscopy, allowing the surgeon to see the internal structures clearly through the tiny camera at the end of the scope.

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What is the difference between the suprapatellar pouch and the suprapatellar bursa?

The anatomy of this region can vary between individuals. The pouch may be split into two by a transverse septum, in which case the upper bit - which is now separate from the joint cavity - is called the suprapatellar bursa. Sometimes the septum is there, but is incomplete, and a 'window' exists between the bursa and the joint cavity proper.

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What is a suprapatellar plica?

The inside of the suprapatellar pouch often has folds, called plicae. If a fold extends right across the cavity, dividing the space into two, then the uppermost part is called a 'suprapatellar bursa' and the fold is called a 'septum' and looks like a membrane stretching right across the pouch. Not everyone has a suprapatellar plica, and a complete septum is rare, but both are considered normal structures unless they get traumatised and interfere with joint mechanics. 

  • Quote from a peer-reviewed paper:

    "Although suprapatellar plicae are found frequently in the knee joint with variable shapes, symptomatic suprapatellar plicae are rarely found....[but]....it is important for orthopedic physicians to consider suprapatellar plica syndrome when treating patients with knee symptoms."

    Citation: Akao M, Ikemoto T, Takata T, Kitamoto K, Deie M. Suprapatellar plica classification and suprapatellar plica syndrome. Asia Pac J Sports Med Arthrosc Rehabil Technol. 2019 Apr 22;17:10-15. doi: 10.1016/j.asmart.2019.03.001. PMID: 31044135; PMCID: PMC6477514.

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Forum discussions

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Synonyms: 
Suprapatellar bursa
SPP
Suprapatellar recess
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Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...

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