body.

Between the vertebræ are pads or cushions of cartilage. These act as
"buffers," and serve to give the spine strength and elasticity and to
prevent friction of one bone on another. Each vertebra consists of a body,
the solid central portion, and a number of projections called processes.
Those which spring from the posterior of each arch are the spinous
processes. In the dorsal region they are plainly seen and felt in thin
persons.

The bones of the spinal column are arranged in three slight and graceful
curves. These curves not only give beauty and strength to the bony
framework of the body, but also assist in the formation of cavities for
important internal organs. This arrangement of elastic pads between the
vertebræ supplies the spine with so many elastic springs, which serve to
break the effect of shock to the brain and the spinal cord from any sudden
jar or injury.

The spinal column rests on a strong three-sided bone called the
sacrum, or sacred-bone, which is wedged in between the hip bones and
forms the keystone of the pelvis. Joined to the lower end of the sacrum is
the coccyx, or cuckoo-bone, a tapering series of little bones.

Experiment 7. Run the tips of the fingers briskly down the
backbone, and the spines of the vertebræ will be tipped with red so that
they can be readily counted. Have the model lean forward with the arms
folded across the chest; this will make the spines of the vertebræ more
prominent.

Experiment 8. _To illustrate the movement of torsion in the spine, or