immovable connection between bones with interlocking projections; provides highest degree of strength but allows no motion

Cranial surface and Sacrum

convex surface of one bone fits into the concave surface of another; permits movement in only one plane

Metacarpals/Phalanges

round head fits into cup-shaped socket; permits greatest range of motion; ball-and-socket

Humerus/Scapula and Femur/Ischium

Flat or slightly curved surfaces oppose one another for sliding motion; permits only slight movement, but in all directions

Between carpals and between tarsals

One bone turns around another bone as its pivot point; permits only rotating movements

Radius/Ulna and Atlas/Axis

two knuckle-shaped surfaces engage corresponding concave surfaces; permits movement in only on plane

Femur/Tibia