Ch10: Enabling Function and Participation With Seating Technologies

Question 1

Acceleration

Answer 1

The rate of change in velocity (increase or decrease)

Question 2

Base of Support

Answer 2

Area around the outside edge of the sections of the body in contact with the ground/surface

Question 3

Center of Gravity

Answer 3

For an object on Earth, hypothetical point where the entire mass of an object may be assumed to be concentrated to visualize its motion

Question 4

Center of Pressure

Answer 4

Center of gravitational forces when measured in posterior-anterior and lateral planes

Question 5

Compression

Answer 5

Occurs when forces act toward each other (pushing together), such as the force of the vertebrae on the disks in the spinal column

Question 6

Contour

Answer 6

Refers to seating devices that are molded or shaped to conform to the human’s body

Question 7

Displacement

Answer 7

Defines the position of a body in space; a change in displacement results in a new position

Question 8

Dampening

Answer 8

The ability of a material to soften on impact

Question 9

Density

Answer 9

The ratio of the weight of a material to its volume

Question 10

Envelopment

Answer 10

The degree to which the person sinks into a seating cushion and the degree to which the cushion surrounds the buttocks

Question 11

Equilibrium

Answer 11

The situation in which the force generated by one object is equal in magnitude and opposite in direction to the force generated by another object

Question 12

Fixed Deformity

Answer 12

A permanent change taking place in the bones, muscles, capsular ligaments, or tendons that restricts the normal range of motion of the particular joint and affects the skeletal alignment of the other joints

Question 13

Flexible Deformity

Answer 13

Appearance of a deformity as a result of increased tone and muscle tightness causing the person to assume certain postures; externally applied resistance (passive stretch) in the opposite direction allows movement of the joint and reduction in the “deformity”

Question 14

Force

Answer 14

Anything that acts on a body to change its acceleration or alter its momentum

Question 15

Friction/Frictional Forces

Answer 15

Resulting forces from movement in opposite directions between two bodies in contact; may be static or dynamic

Question 16

Gravitational Line

Answer 16

The axis of the body along which the force of gravity acts

Question 17

Gravity

Answer 17

Acceleration of an object toward the center of the earth

Question 18

Immersion

Answer 18

Describes the deformity that results when a load is applied to a material, including materials used to produce a seat cushion

Question 19

Kinematics

Answer 19

Aspect of mechanics that describes the motion of a mass, without consideration of the forces involved in that motion

Question 20

Kinetics

Answer 20

Aspect of mechanics that describes the actions of forces to produce or change motion of a mass

Question 21

Line of Application

Answer 21

The particular direction along which forces are applied, either pushing or pulling

Question 22

Linear (displacement)

Answer 22

The situation that occurs when all parts of a body move in the same direction, at the same time, and for the same distance

Question 23

Magnitude

Answer 23

The amount or size of a measurement; when considering force, magnitude is measured in Newtons, pounds or kilograms

Question 24

Mobility

Answer 24

Allows movement that enables function in a seated or standing position

Question 25

Pelvic Obliquity

Answer 25

One side of the pelvis is higher than the other when viewed in the frontal plane

Question 26

Pelvic Rotation

Answer 26

One side of the pelvis is forward of the other side with rotation in a lateral plane

Question 27

Planar (seating system)

Answer 27

Flat seating components that support the body only where it easily comes into contact with the supporting system

Question 28

Postural Control

Answer 28

Control provided by either internal (neuromusculoskeletal structures) or external positioning devices (e.g., seating components, tilt, recline) to enable a stable and functional position

Question 29

Pressure

Answer 29

Force per unit area

Question 30

Pressure Mapping

Answer 30

Data collection systems that involve quantification of pressure at an interface and translate these data into a visual map

Question 31

Pressure Redistribution

Answer 31

Goal or outcome of seating technology that results in change in the distribution of pressure to relieve areas of high pressure, commonly under the ischial tuberosities or coccyx in sitting

Question 32

Pressure Ulcer

Answer 32

A lesion that develops as a result of unrelieved pressure to an area and that results in damage to underlying tissue

Question 33

Recovery

Answer 33

The degree to which a seating cushion returns to a preloaded state when its load is removed

Question 34

Resilience

Answer 34

The ability of a material to recover its shape after a load is removed or to adjust to a load as it is applied

Question 35

Restraint

Answer 35

Any manual method or physical or mechanical device, material, or equipment attached or adjacent to a person’s body that the individual cannot remove easily, which restricts freedom of movement or normal access to one’s body

Question 36

Rotational (displacement)

Answer 36

The situation that occurs when all parts of a body move around an axis (the fulcrum)

Question 37

Scoliosis

Answer 37

Lateral or rotational curvature of the spine

Question 38

Shear

Answer 38

Occurs when forces are parallel (sliding across the surfaces), such as the movement that occurs as the head of the femur moves across the acetabulum during hip movement; when shear force is present, deep structures move in the direction of the applied force while superficial structures remain immobile

Question 39

Sliding Resistance

Answer 39

A cushion property related to friction that describes the forces that influence movement of the user across the surface of a seat cushion

Question 40

Stability

Answer 40

Postural control that allows an individual to maintain an upright seated position

Question 41

Stability Zone

Answer 41

The balance limits for a person in either sitting or standing

Question 42

Stiffness

Answer 42

How much a material gives under load

Question 43

Stress

Answer 43

The resulting molecular change inside biological (ex. soft tissue and bone) or nonbiological (ex. metals, plastics, or foams) materials

Question 44

Support Surfaces

Answer 44

Device designed to redistribute pressure or enable postural control; in seating technology, this term typically refers to a seat cushion or back

Question 45

Tension

Answer 45

Forces that act in the same line but away from each other (pulling apart), such as the force applied on the antagonist muscle during contraction of the agonist muscle

Question 46

Windswept Hip Deformity

Answer 46

When one hip is adducted and the other hip is abducted