~10. The Arms.~--Each of the arms has five bones, besides the small
bones of the hand. They are the _collar-bone_, which connects the
shoulder to the breast-bone, the _shoulder-blade_, at the back of the
shoulders, the _upper arm-bone_, between the shoulder and the elbow, and
the two _lower arm-bones_, between the elbow and the wrist. There are
eight little bones in the wrist, five in that part of the hand next to
the wrist, and fourteen in the fingers and thumb.

~11. The Legs.~--The bones of the leg are the _thigh_ or _upper
leg-bone_, the _knee-pan_ or _knee-cap_, which covers the front of the
knee, the two bones of the _lower leg_, the _heel-bone_ and six other
bones in the _ankle_, five bones in that part of the foot next to the
ankle, and fourteen bones in the _toes_.

~12. Use of the Bones.~--The skeleton is not only necessary as a
framework for the body, but it is useful in other ways. Some of the
bones, as the skull, protect delicate parts. The brain is so soft and
delicate that it would be very unsafe without its solid bony covering.
The spinal cord also needs the protection which it finds in the strong
but flexible back-bone. The bones help to move our hands and arms, and
assist us in walking.

~13. The Joints.~--The places where two or more bones are fastened
together are called _joints_. Some joints we can move very freely, as
those of the shoulder and the hip. Others have no motion at all, as
those of the bones of the skull.

~14. Cartilage.~--The ends of bones which come together to form a joint
are covered with a smooth, tough substance, which protects the bone from