Joints of the Human Skeleton

Away from the skull, different joints of the body are shaped for the particular movement each location needs. The joint between the atlas and the axis (the first two neck vertebrae) is a pivot joint, allowing the head to rotate from side to side; the joint at the base of the thumb, between its carpal and metacarpal bone, is a saddle joint, which is what lets the thumb swing across the palm to oppose the fingers. The atlanto-axial joint (again, atlas on axis) is this same pivot joint, while the joint between the femur and the acetabulum of the hip bone is a ball-and-socket joint, permitting movement in almost every direction — flexion, extension, abduction, adduction and rotation. The sutures joining the bones of the cranium are fibrous, immovable joints, in clear contrast to the joints between the small tarsal bones of the foot, which are gliding (plane) joints allowing only a limited sliding movement against one another. …