Answer the following. (a) What is a ball and socket joint? (b) Which of the skull bones are movable? (c) Why can our elbow not move backwards

Solution:

1. a) The rounded end of one bone fits into the cavity (hollow space) of the other bone. Such a joint allows movements in all directions, which is called a ball and socket joint.
2. b) Lower jaw
3. c) Our elbow cannot move backwards because it has hinge joints which only allow back-and forth-movement.