Amputation Glossary of Terms!

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New to the world of amputation/prosthetics? Here are a list of terms defined so you can stay in the know! 

AK amputation or prosthesis - Above-the-knee (transfemoral)
Alignment - The relative spatial orientation of the components comprising a prosthesis; or the orientation of the prosthesis to the human body.
Amputation - The loss or absence of all or part of a limb.
Assistive/adaptive equipment: Devices that assist in performance or mobility, including ramps and bars, changes in furniture heights, environmental control units and specially designed devices. 
BK amputation or prosthesis - Below-the-knee (transtibial)
Bilateral Amputee - A person missing both limbs (legs or arms). Bi = "two" Lateral = "side"
Biomechanics - The application of engineering or mechanical principles to biological systems such as the human body or its segments.
Bionics - The application of biological principles or mimicry to mechanical devices often by using microprocessor control.

Bumper A compliant (polymer based) part installed into a prosthetic component to aid extension or resistance or to soften impact at the end range of motion. They are often available in different durometers to allow customization of the component for the amputees needs/preferences.
Carbon Fiber - The ultra durable, high tensile strength material used in the fabrication of dynamic and energy storing components as well as in the fabrication of prosthetic sockets. Also widely used in the aerospace industry.
Check or Test Socket - A temporary socket, often transparent, made over the plaster model to aid in obtaining a proper fit.  A successful test socket will then be remade into the definitive socket. Often used for 2-4 weeks. 

Congenital Amputee -  Individual born missing a limb(s).  Technically, these individuals are not Amputees, but are considered to be "Limb Deficient.”
Cosmesis - The natural appearance of a prosthesis achieved by a lifelike covering fitted over its components.
Cover - Also referred to as 'anatomical form', 'anatomical restoration', 'cosmesis' or 'finish' -The external shape and surface detail of a prosthesis. This can range from extremely high definition life-like silicone restorations to basic anatomical shape restoration to sleek carbon fibre and 'industrial' design.

Stump Distal End- Anatomical term denoting "away from" the center of the body (opposite of proximal). 

Durometer – Measure of hardness of a material, typically polymers, elastomers, or rubbers.

Endoskeletal Prosthesis - A prosthetic device in which the support structure is internal, similar to the human skeleton. An anatomical form can be added which would give the prosthesis a more human appearance.

Energy-storing Foot - Also referred to as 'Dynamic Foot' or 'Energy Returning Foot'- A prosthetic foot whose structural element (keel) will distort or bend, storing energy during certain phases of the gait cycle; this stored energy is returned in later phases of the gait cycle as the keel returns to its original shape. As a result the amputee uses less energy to walk.
Exoskeletal Prosthesis - A prosthetic device in which the support structure is its external shape. Ideally suited for water activity prostheses as it can be made hollow and neutrally buoyant; it will fill with water when submerged so it doesn't float, then drain when above the surface of the water. 
Hemi-pelvectomy - An amputation where approximately half the pelvis bone is removed.

Hip Disarticulation - Amputation of the entire leg through the hip joint. 
Knee Disarticulation - The distal femur is left intact in order to allow distal weight bearing.
Lateral - Anatomical term denoting away from the midline of the body or limb segment in the frontal plane. (opposite of medial) 
Liner - A gel (silicon, urethane or thermoplastic elastomer (TPE)) interface 'sock' that is worn directly against the skin within a prosthesis. It is designed to stabilize and protect the skin, soft tissue and bony anatomy of the residual limb within the structural element of the prosthetic socket. Liners vary in thickness, gel durometer and gel profile. They can also have integrated suspension options such as a threaded fitting on the end for a lock or a seal for suction. 

Medial - Anatomical term denoting towards the midline of the body or limb segment in the frontal plane.  (opposite of lateral) 

Partial Foot – Wide range of amputation level where part of the foot is removed.
Prosthesis – A device used to replace an extremity that is partially or totally missing; commonly referred to as an artificial limb (plural is prostheses).

Proximal – Anatomical term denoting ‘towards’ the center of the body (opposite of distal).
Pylon - The structural element of a prosthesis that connects its major components; eg. Socket to foot or foot to knee.

Residual Limb – Also informally referred to as a "stump," the part of the limb that remains after an amputation surgery.
Sock - prosthetic sock or filler sock-One of any number of types of textile (cotton, wool, nylon or blend) linings that are worn within the  prosthetic socket. They can be used to wick perspiration away from the skin, shield the skin from shear forces and adjust the tension within the socket (by changing the thickness or number of socks). Throughout the day, it may be necessary to adjust the thickness (or 'ply') of socks worn.

Socket - The portion of the prosthesis that is custom made to accommodate the amputee's residual limb; incorporating interface, suspension and support elements, the socket links the amputee and his/her prosthesis.

Suspension - The element of the prosthesis that holds the socket to the patients residual limb when in a non-weight bearing or 'open chain' state (eg, when the foot is off the floor). There is a large variety of suspension methods, including:

  • Suction - A seal is made between the residual limb and the prosthesis that doesn't allow air to enter the socket. A suspension sleeve and air expulsion valve may be incorporated.
  • Elevated vacuum - Similar to suction, but a vacuum pump is utilized to generate higher levels of vacuum than can be generated with passive suction.
  • Locking liner - Some liners have a threaded fitting incorporated into the distal end into which a 'pin' or lanyard can be mounted. A lock with a push-button release can be fabricated into the socket that will accept the pin or lanyard.
  • Seal-In liners - A sealing membrane is fabricated onto the outer surface of the interface liner that is designed to make contact with the socket walls, creating a suction 'zone' distal to the membrane. This system requires an air expulsion valve mounted in the bottom of the socket.
  • Suspension sleeve - Sleeve that spans the brim of the socket to provide a mechanical link between the prosthesis and the patient's limb. Can also be used to create a seal in a suction or vacuum socket.
  • PTB strap/cuff - Used with a trans-tibial prosthesis, a strap that fastens above the knee and is attached to the socket.
  • Thigh corset - A proximal extension to a trans-tibial prosthesis that attaches to the socket with external knee joints and struts or uprights. Provides additional knee stability, weight bearing and rotational control.
  • Anatomical self-suspension - A socket that suspends itself utilizing anatomical features of the residual limb.
  • Waist belt - The suspended weight of the prosthesis is supported by a belt around the amputee's waist
  • Harness - The suspended weight of the prosthesis is supported by a harness over the amputee's shoulders. (far more common in upper limb prosthetics than lower limb)
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