When operating, surgeons need to make use of a variety of instruments which help them hold back any tissue which obscures the area on which they are operating. The main instruments which are used in this process are called retractors. It is due to these specific instruments that a surgeon can easily conduct the operation without damaging any of the nearby tissue retractors can be found in many designs, sizes and shapes. Since retractors have a huge variety, they are generally known for the organ on which they are to be used. Examples of specific retractors include an abdominal retractor, a skin retractor or a lung retractor. There are also some retractors which are named after the person who came up with them such as the Balfour retractor. The basic purpose of each of these retractors is quite similar however since each of them are meant for a particular organ, their function varies. There are some retractors available which help in keeping the edges of any incision separate. Then there are others which ensure that no organ hinders the area where the surgeon is performing his procedure retractors generally come in two types; self retaining and hand held. Hand held retractors are to be held by the assistants while the procedure takes place whereas the self retaining retractors can simply be locked into the appropriate place and made to maintain the position they are kept at. Once the position has been fixed, it does not need to be held manually. Even though hand held retractors are considered to be more flexible, it is easier to maintain a certain retraction level while using the self retaining retractor. Depending on the function of each retractor, the blade as well as the handle is designed in a variety of styles. The size of each of these can also vary as every individual has a different sized hand.