132).
*The Pons*, or pons Varolii, named from its supposed resemblance to a
bridge, is situated in front of the cerebellum, and is readily recognized
as a circular expansion which extends forward from that body. It consists
largely of bands of nerve fibers, between which are several small masses
of cell-bodies. The fibers connect with different parts of the cerebellum
and with parts above.
[Fig. 132]
Fig. 132--*Human brain* viewed from below. _C._ Cerebrum. _Cb._ Cerebellum.
_M._ Midbrain. _P._ Pons. _B._ Bulb. I-XII. Cranial nerves.
*The Bulb*, or medulla oblongata, is, properly speaking, an enlargement of
the spinal cord within the cranial cavity. It is somewhat triangular in
shape, and lies immediately below the cerebellum. It contains important
clusters of cell-bodies, as well as the nerve fibers that pass from the
spinal cord to the brain.
*The Spinal Cord.*--This division of the central nervous system is about
seventeen inches in length and two thirds of an inch in diameter. It does
not extend the entire length of the spinal cavity, as might be supposed,
but terminates at the lower margin of the first lumbar vertebra.(100) It
connects at the upper end with the bulb, and terminates at the lower
extremity in a number of large nerve roots, which are continuous with the
nerves of the hips and legs (Fig.
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