Diagram showing AV fistula for hemodialysis

This drawing shows an AV fistula in a person's arm. An AV fistula is under the skin. A doctor makes an AV fistula by doing surgery to connect an artery directly to a vein. It is usually done in the lower arm but can be done in the upper arm. During hemodialysis, two needles are put into the access to remove and return blood to the body.