special subjects
Prosthesis Parts
Suspension
Suspension refers to how the prosthesis is held to the residual limb. Certain gel interface materials are better suited for specific suspension applications (such as suction, pin, or vacuum). The following suspension systems are commonly used: Vacuum:An electric or mechanical vacuum pump removes air from the socket. This is the most effective method for holding a prosthesis to the residual limb and also helps stabilize the amount of fluid in the residual limb. Urethane gel interface materials are preferred for this type of suspension. Passive suction:When the residual limb is put in the socket, air is forced out. A seal above prevents air from reentering, creating suction. A one-way valve may be incorporated in the bottom of the socket to allow air out. Interface with a locking pin:A cushion interface that has a removable, adjustable stainless steel suspension pin at the bottom is inserted into a locking mechanism in the bottom of the plastic socket. To remove the prosthesis, the person presses a release button to disengage the pin. Anatomical:Bumps at the ends of bones, such as at the knee, ankle, or elbow, can be used to help hold the socket to the body. Belts and straps:A belt and/or straps may be used to hold the prosthesis on if the person cannot tolerate or finds the vacuum, suction, or pin systems too difficult. 