This is the most frequent use of the term. It is used to identify a "floating" kneecap, which indicates a moderate-to-large accumulation of fluid (effusion) within the knee joint.
Use one hand to firmly stroke downward from the mid-thigh toward the kneecap. This "milks" fluid out of the suprapatellar pouch and into the space behind the patella.
In pregnancy, ballottement is a "probable sign" used to detect the fetus as it floats in amniotic fluid. ballottement
The patella feels like it is "floating." You will feel it move through fluid, click against the femur, and then rebound or "ballotte" back toward your finger.
The patella is already in contact with the bone; there is no sensation of floating or clicking. This is the most frequent use of the term
Performed by applying a sharp tap to the abdominal wall to feel the fetus move away and return. 3. Abdominal Ballottement
Suspected knee trauma, arthritis flare-up, or unexplained swelling. Technique: This "milks" fluid out of the suprapatellar pouch
This test is highly specific for large effusions but may miss smaller amounts of fluid, which are better detected using the Bulge Sign . 2. Obstetric Ballottement