This section is from the book "The Human Body: An Elementary Text-Book Of Anatomy, Physiology, And Hygiene", by H. Newell Martin. Also available from Amazon: The Human Body.
If the pieces forming the hard framework of the body were put together like the beams and planks of a frame house, the whole mass would be rigid and immovable ; we could not raise a hand to the mouth, or put one foot before another. In order to attain mobility the bony skeleton is made up of more than two hundred separate pieces, joined together; the points where they meet are called articulations. An articulation at which a considerable range of movement is permitted is called a joint. The ends of bones which rub over one another in a joint are always covered by a very smooth layer of cartilage.
For what purposes ? What would be left if all materials composing the body except its connective tissue were dissolved away ?
Fig. 8. The bony and cartilaginous skeleton.