Knee acoustic matching device for ultrasonic probe

An acoustic matching device for a knee for an ultrasonic probe and which is mounted on a knee cap of a bent knee, the acoustic matching device for knee comprising:

• a water bag containing water;
• and
• a water bag support frame which sandwiches and supports the water bag at a left side and a right side of the knee and which is curved along the knee cap, wherein
• the water bag has a plate shape which is curved according to the shape of the water bag support frame, and
• wherein the water bag comprises a fixed portion having a side supported by the water bag support frame, and a free portion which extends from the fixed portion toward a distal side and which is allowed to move in a front and rear direction of the knee.