Use the specimen on which the muscles were dissected. (Or if the
peripheral nerves are not to be dissected on the specimen used for the
blood-vessels, that may be employed.)
Make a longitudinal dorsal median incision of the skin, between the back
of the head and root of the tail. Reflect the skin for one or two inches
on each side of the incision and cut away the muscles covering the
neural arches of the vertebræ from the third cervical to the seventh or
eighth thoracic inclusive.
Remove with bone-forceps the neural arch of one of the last cervical
vertebræ and find the spinal nerve emerging from the intervertebral
foramen. Isolate the nerve for a short distance, then proceed craniad,
removing the neural arches on one side and isolating the nerves until
the third has been uncovered. The ganglion of the second nerve should be
sought among the muscles on the dorsal surface between the atlas and
axis, and after it has been isolated the arch of the axis may be
removed. (The nerve may be found beneath the clavotrapezius and traced
to the ganglion.)
The ganglion of the second nerve should be isolated in or near the
atlantal foramen, the muscles to which it passes turned aside, and the
arch of the atlas removed. Having thus uncovered the first two or more
spinal ganglia, proceed caudad, removing the vertebral arches, until the
whole cord and its nerves are exposed. Then--
1. Study the cord, enlargements, filum terminale, etc. (p. 334, and
Figs. 133 and 136).