Joints

Question 1

Ball & Socket

Answer 1

The ball-like head of one bone fits into the socket-like head of another, permitting all movements. Example: shoulder and hip.

Question 2

Ellipsoid

Answer 2

This is a reduced ball and socket configuration in which rotation is not permitted. Example: radiocarpal joint.

Question 3

Gliding

Answer 3

Two opposed flat surfaces of bone glide across one another. Movement is limited to gliding. Example: intercarpal joints.

Question 4

Hinge

Answer 4

The C-shaped surface of one bone swings about the rounded surface of another. Movement is limited to flexion/extension. Example: elbow, ankle, interphalangeal joints.

Question 5

Pivot

Answer 5

A ring of bone rotates about a process of bone. Movement is limited to rotation. Example: the skull on the atlas (1st cervical vertebra) rotates about the odontoid process of the 2nd cervical vertebra.

Question 6

Saddle

Answer 6

The concave surfaces of two bones articulate with one another. All movements are possible, but rotation is limited. Example: carpometacarpal joint of the thumb.