Levers, planes and axes

Levers

Forms from bones, joints and muscles

Levers consist of

rigid structure, a force acting upon it to produce a turning movement, a fulcrum and a load or resistance placed on the structure

mechanical advantage

effort arm/ resistance arm, means they can overcome large resistance with little effort.

First class lever

fulcrum is in the middle of the effort and the load eg neck

second class lever

load is in the middle of the fulcrum and the effort eg ankle

third class lever

effort is in the middle of the fulcrum and the load

Mechanical disadvantage

when a levers load arm is longer than its effort arm

Fulcrum

the join

effort

muscle/action happening

load

weight/resistance

frontal axis

line passing through the body horizontally from left to right

vertical axis

line passing through the body vertically from top to bottom

sagittal axis

line passing through the body horizontally from front to back

Plane

Imaginary line or flat surface that is used to divide the body

Sagittal plane

line dividing the body vertically into left and right sides

Frontal plane

line dividing the body vertically into front and back

Transverse plane

line dividing the body horizontally into top and bottom

Match sagittal axis

with frontal plane

Match frontal axis

with sagittal plane

Match vertical axis

with transverse plane