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 backward?

(a) The ball and socket joint (or spheroid joint) is a type of synovial joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes, which have one common center.

The ball and socket joint provides swinging and rotating movements.

For example: The hip joint, shoulder joint, and the first and second vertebrae of the neck that allows the head to move back and forth.

\r

                                     

(b) Lower jaw bone, also known as Mandible bone, is the only movable skull bone.

                                      

(c) Our elbow is an example of the synovial hinge joint between the humerus in the upper arm and the radius and ulna in the forearm that allows the forearm and hand to be moved in only one direction (forward direction), away from the body.

These joints are formed when two or more bones meet and move along an axis to bend.

Therefore, we can't move our elbow backwards.