PRACTICAL DIRECTIONS. 469 
397) by removing the integument from the medial side of the leg 
(see Fig. 127, p. 310). To dissect the sacral nerves (p. 399) separate 
the innominate bones at the pubic symphysis and divaricate them. 
Find the nerves arising from the sacral plexus, by cutting the levator 
ani muscle. After N. hemorrhoidalis inferior and N. pudendus have 
been traced, ‘the rectum and urogenital organs may be removed, tak- 
ing great care not to remove more than is necessary. To dissect the 
great sciatic nerve (p. 400, and Fig. 163), separate the biceps and 
.caudofemoralis near their proximal ends and find the large nerve- 
trunk (a2). Then lift the biceps away from the nerve, cut that muscle 
near its middle, and reflect it. The nerve may now be followed to 
its terminal branches; during the process cut the muscles only when 
absolutely necessary. The inferior gluteal nerve (7) will be found 
on the dorsal surface of the great sciatic; by cutting the caudofemo- 
ralis and gluteus maximus muscles near their insertions and turning 
them back the distribution of the nerve may be followed. The 
superior gluteal (7) will be found at the cranial margin of the pyri- 
formis by reflecting the gluteus medius in the same way; the tensor 
fascie latee may also be cut. 
SENSE-ORGANS, 
I. Tue Eve (p. 410). 
Use any specimen on which one side of the head has been left 
intact. Remove the head from the body by cutting through the neck 
a little craniad of the first rib. 
Study the eye externally. Observe the eyelids, the conjunc- 
tiva, nictitating membrane with its cartilage, and the Harderian 
gland (Fig. 165); the two openings of the lachrymal duct, the 
Meibomian glands if possible. 
Remove the zygomatic arch and expose the orbit and the struc- 
tures which it contains. Study the periorbita (p. 409), and find the 
lachrymal gland (p. 410). 
Study the muscles of the, eyeball (p. 411, and Fig. 166). The 
lateral rectus on the lateral surface will perhaps be first found, and 
its tendon traced beneath the inferior oblique. Use great care not 
to injure the levator palpebrz superioris. 
After studying the muscles, find the optic nerve. Cut it and the 
muscles, and remove the eyeball for farther study. 
The Eyeball (p. 412, and Fig. 167).—For an examination of the 
eye it is well to have a fresh specimen and one hardened in formalin 
or alcohol. The hardened specimen is more essential, however. An 
eye from one of the specimens used in dissection is usually satisfac- 
tory. All accessory portions should be trimmed from the eyeball, 
leaving only the spherical ball with a short stalk formed by the optic 
nerve. 
Dhaarwa ench foatnrac af the eve ac can he seen externally: the 
