What is a Baker’s cyst?

What is a Baker’s cyst?

A Baker’s cyst, also known as a popliteal cyst or synovial cyst, is a soft, fluid-filled lump that forms on the back of your knee. Like many diseases and disorders, this cyst is named after the doctor who first described it. In the mid-1800s, Dr. William Morrant Baker concluded that these popliteal cysts resulted from fluid flowing out from a damaged knee joint. When structures in or around the joint are damaged, your knee produces extra fluid that can only flow one way so it forms a cyst on the back of your knee.