107
Muscle magic
Muscles are rubbery,
stretchy straps.
You can control
some of your muscles,
like the muscles in your
arms and legs. Others,
such as your heart and
bladder, operate without
you having to think
about it.
Making faces
Muscles in your face are
attached to skin as well as
bone. They allow you to
make all kinds of expressions
to show how you are feeling.
Bones and muscles
There are 206 bones in an adult skeleton.
Ankles
contain different
joints for up-and-down
and side-to-side movement.
Wrists
have a joint that
allows them to turn but
not go all the way round.
Neck
bones feature a
pivot joint that allows
your head to turn.
Thumbs
have joints that
allow them to rotate,
which fingers cannot do.
Bending bits
Different kinds of joints
all over your body keep
you moving.
Pulling pairs
Muscles can pull
but they can’t
push. They work in
pairs that pull in
opposite directions.
Biceps and
triceps bend
and straighten
your arm.
The pectoralis
muscle moves
your arm at the
shoulder.
The biceps
contract to pull
the forearm up.
The tibialis
muscle bends
your foot.
The triceps relax
and stretch when
the biceps contract.
