The prepatellar bursa is a frontal bursa of the knee joint. It is a superficial bursa

Bursa (anatomy)

A bursa is a small fluid-filled sac lined by synovial membrane with an inner capillary layer of slimy fluid . It provides a cushion between bones and tendons and/or muscles around a joint. This helps to reduce friction between the bones and allows free movement...

 with a thin synovial

Synovium

Synovial membrane is the soft tissue found between the articular capsule and the joint cavity of synovial joints....

 lining located between the skin and the patella.

Pathology

Prepatellar bursitis

Prepatellar bursitis

Prepatellar bursitis, also known as Housemaid's knee, is a common cause of swelling and pain above the patella , and is due to inflammation of the prepatellar bursa. This structure is a superficial bursa with a thin synovial lining located between the skin and the patella...

, also known as housemaid's knee, is a common cause of swelling and pain above the patella (kneecap), and is due to inflammation of the prepatellar bursa. This is also common in roofers, plumbers, carpet layers and gardeners.

Symptoms include knee pain, swelling, redness and inability to flex the knee on the affected side. Rest usually relieves symptoms. Physical exam reveals erythema

Erythema

Erythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation...

, tenderness to touch, fluctuant edema

Edema

Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...

 over the lower pole of the patella and crepitus

Crepitus

Crepitus is a medical term to describe the grating, crackling or popping sounds and sensations experienced under the skin and joints.-Causes:...

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