Re: How does the neck work?

That's a nice question, Evi.  There are seven cervical vertebrae 
altogether.

The top vertebra, C1, aka the atlas*, is quite narrow from top to bottom.  
It supports the skull like a hand cupping a ball.  It has a shaped hole at 
the back which acts like a socket.  The second vertebra, C2, aka the 
axis**, has a bit of bone shaped somewhat like the top joint of a thumb 
which sticks up and fits into C1's socket.  Together they enable a side to 
side movement, i.e.  head straight up, eyes to the horizon, and look to 
one side or the other without tilting the head in any other direction.
*  Named after the ancient Greek god Atlas, who carried the world on his 
shoulders
**  Greek word meaning turning point or axle, i.e. of a wheel

The back and forth movement (chin up, chin down) is done by interactions 
between axis and C3, C4.

A sideways movement (eyes forward, bring one ear towards the shoulder on 
the same side, other ear to other shoulder) happens at C4 C5 and C6

The bones' shapes decide where and how in the body movement can be made, 
but these movements are controlled by the attached muscles and ligaments.

If your local library permits access, there is an anatomy book with 
stunningly beautiful and accurate drawings of bones, muscles etc. which I 
recommend.
ANATOMY, A Regional Atlas of the Human Body, by Carmine D. Clemente, a 
professor at UCLA school of medicine.
publishers:  Urban & Schwarzenberg, ISBN 0-8067-0323-7

regards.
Bobby

bobby@catalase.com