UPMSP Artificial Limb & Organ Tech key terms

The standard reference stance in which a person stands upright, faces forward, arms hang at the sides with palms turned forward, and feet point ahead, so that all body directions and limb alignments can be described consistently.

Directional words describing position along a limb: proximal means nearer to the trunk or root of the limb, while distal means farther from it, toward the hand or foot. These terms guide socket trim lines and component placement.

The measured arc through which a joint can move, usually expressed in degrees and recorded as active when the patient moves it or passive when the examiner moves it. It sets goals for prosthetic and orthotic design.

A permanent shortening of muscle and connective tissue around a joint that limits movement and cannot be corrected by passive stretching alone. It commonly follows disuse or poor positioning and may prevent comfortable prosthetic fitting.

The portion of a limb remaining after amputation, including bone, muscle, scar, and soft tissue. Its length, shape, sensation, and healing quality strongly influence socket design and comfort.

Regions of the residual limb or body that can safely tolerate pressure from a prosthesis or orthosis, such as the patellar tendon bar area in a below-knee limb. Identifying them prevents skin damage during weight bearing.

A mapping of the limb surface into zones that can accept load and zones that cannot, such as bony prominences, scars, and nerve pathways. Socket and orthosis shapes are modified so force is shifted away from sensitive zones.

A localized hollow or added space built into a cast, positive model, or socket wall so that a bony prominence, tender scar, or artery is not pressed during wear. It is created by adding padding before casting or by carving the model.

A hollow impression of the limb taken in plaster or a similar material, capturing its shape in reverse. It is filled with plaster to produce a positive model used for socket fabrication.

A solid replica of the limb produced by filling a negative cast, then corrected and smoothed before being used to form a socket or orthosis. It carries all modifications such as reliefs, buildups, and trim lines.

The deliberate reshaping of a positive model by adding or removing material so the finished socket loads tolerant areas, relieves sensitive ones, and controls suspension. It converts an anatomical copy into a functional interface.

The hollow, custom-formed part of a prosthesis that receives the residual limb and transmits body weight and control forces to the rest of the device. Its fit, shape, and suspension determine comfort and function.

The method that holds a prosthesis on the limb during swing and lift, using suction, a liner and pin, a belt, a sleeve, or anatomical locking. Poor suspension causes pistoning, rubbing, and loss of control.

Up-and-down sliding of the residual limb inside the socket during walking, caused by a loose fit, weak suspension, or volume change. It produces friction, skin breakdown, and reduced control of the prosthesis.

Monitoring and controlling changes in residual limb size using shrinkers, elastic wrapping, prosthetic socks, or socket adjustments. Limb volume shifts with swelling, weight change, and activity, so fit must be rechecked regularly.

The initial setup of prosthetic components on a workbench using reference lines and the manufacturer's suggested angles before the patient stands in the device. It gives a sound starting point for later dynamic adjustment.

Fine adjustment of the prosthesis while the patient stands and walks, changing angles, shifts, and lengths until gait is stable and comfortable. It relies on observation and patient feedback rather than bench measurements alone.

A vertical reference line dropped from the greater trochanter of the femur, used in bench and static alignment to judge whether the socket and foot are correctly positioned relative to the body's line of weight bearing.

One complete sequence of walking from initial contact of one foot to the next contact of the same foot, divided into stance and swing phases. Understanding it is essential for identifying deviations and tuning alignment.

The part of the gait cycle when the foot is on the ground and bearing weight, normally about sixty percent of the cycle. It is when stability, knee control, and prosthetic foot function are tested most.

The part of the gait cycle when the foot is off the ground and moving forward, normally about forty percent of the cycle. Clearance, knee flexion, and suspension are mainly judged during this phase.

An instrument with a hinged arm and protractor scale used to measure joint angles and range of motion. Measurements taken with it document baseline function and guide prosthetic or orthotic prescription.

A polymer that softens when heated and hardens on cooling, so it can be reshaped repeatedly. Materials such as polypropylene and polyethylene are widely used for prosthetic sockets and orthotic shells.

A polymer that cures permanently through a chemical reaction and cannot be remelted or reshaped. Acrylic and epoxy resins are used for laminating sockets and for rigid orthotic components.

Building a rigid prosthetic or orthotic shell by laying reinforcing fabric such as fiberglass or carbon fiber over a model and saturating it with resin that then cures. Resin-to-fiber ratio strongly affects strength and weight.

A material of carbon fibers embedded in resin, giving very high stiffness and strength at low weight. It is common in energy-storing feet, lightweight sockets, and orthotic frames.

A fabrication method in which a heated thermoplastic sheet is drawn tightly over a positive model by suction, then cooled to hold the shape. It produces thin, even sockets and orthotic shells with good reproduction of detail.

The ability of a material in contact with skin or tissue to avoid causing irritation, allergy, or toxic reaction. It is a key selection criterion for liners, adhesives, and any device worn against the body.

A soft, elastic sleeve worn between the residual limb and the socket to cushion pressure, protect skin, and assist suspension, often with a locking pin or sealing rings. Its thickness and stiffness affect comfort and control.

The part of a below-knee prosthetic socket or orthosis that bears weight under the ischial tuberosity, helping control rotation and provide a stable sitting surface. Its position is checked during fitting and alignment.

A prominent ridge built into the front of a below-knee socket that presses just below the kneecap on the patellar tendon, a pressure-tolerant area. It helps suspend the socket and resist rotation.

A device worn around the lower leg and foot that controls ankle motion and position, commonly used to correct drop foot or provide stability. It may be made of plastic, metal, or carbon composite.

A principle in orthotics and fracture bracing in which forces applied at three points create a bending moment that holds a limb or joint in a corrected position. The middle force is opposite the two end forces.

An externally applied device that supports, aligns, protects, or corrects a body segment or joint. Unlike a prosthesis, it works alongside an existing body part rather than replacing a missing one.

An artificial device that replaces a missing body part, such as a hand, leg, or eye, and aims to restore appearance or function. Its design must balance comfort, durability, and the patient's daily needs.

Operation of an electric hand or arm by electrical signals picked up from muscles on the residual limb using surface electrodes. It requires good electrode contact and patient training to produce reliable, repeatable grips.

An upper-limb prosthesis operated by a harness and cable that transmits shoulder and trunk movement to open a terminal device. It is durable, light, and gives useful feedback through the cable tension.

The hand or hook at the end of an upper-limb prosthesis that grips objects. Hooks offer precision and visibility, while prosthetic hands give a more natural appearance and broader contact surface.

Damage to the skin from prolonged pressure, shear, or friction against a device, ranging from redness to open sores. It signals poor fit or hygiene and must be addressed before the device is worn again.

The experience of feeling or sensing a limb that has been amputated, which is common and usually fades over time. It differs from phantom pain and should be discussed openly with the patient during assessment.

A graded rehabilitation technique in which the residual limb is progressively exposed to touch, tapping, and pressure to reduce hypersensitivity and prepare it for socket wear. It is taught as a home exercise.

Any condition, material, or action in the workshop that can harm health, such as dust, fumes, noise, sharp tools, or heavy lifts. Recognizing hazards is the first step in controlling risk.

Wearable gear such as goggles, gloves, dust masks, and hearing protection that reduces exposure to workshop hazards. It is a last line of defense and does not replace proper guards, ventilation, or safe methods.

Physical barriers and interlocks fitted around moving parts of tools such as saws, drills, and grinders to prevent contact with hands or clothing. Guards must never be removed or bypassed during work.

A patient's voluntary agreement to a procedure after receiving clear information about its purpose, benefits, risks, and alternatives. It respects autonomy and must be documented before fitting or treatment begins.

The ethical duty to keep a patient's personal and medical information private and share it only with those who need it for care. It builds trust and is a legal obligation in most settings.

A structured evaluation of a patient's history, physical condition, limb shape, mobility, and goals before designing a prosthesis or orthosis. It gathers the facts that justify the prescription and fitting plan.