I. The nasal cavity (p. 243). Review the description of the nasal cavity
given under the Bones (p. 59). Study the cartilaginous framework that
supports the external nose (p. 243); make a cross-section of the
framework near the end of the nose and verify the description (p. 244,
and Fig. 103). Without injuring the larynx or tongue saw through the
head in a vertical plane and a little to one side of the median line.
(If desired, the brain may first be removed from the specimen and
preserved for future study. For directions, see page 462. The removal of
the brain does not injure the head for the study of the nasal cavity;
the skull may be sawn lengthwise in the same way as before.) Wash out
the cut surfaces before examining. Find the ventral conchæ (p. 40), the
labyrinths of the ethmoid (p. 43), the inferior meatus of the nose (p.
243), and by bristles the lachrymal duct or canal (p. 245). The
lachrymal duct is conveniently found by passing bristles into the
openings of the lachrymal canals. One of these is to be found on the
border of each eyelid, two or three millimeters from the inner angle of
the eye (see p. 410).
Cut the œsophagus and trachea at the point where the blowpipe was
inserted into the trachea. Separate the tongue, hyoid, larynx,
œsophagus, and first part of the trachea from the adjacent parts and
remove them.
II. The larynx (p. 246). (1) Read the description, studying the
cartilages (p. 247) on a preparation (Fig. 104). Then very carefully
remove the pharynx and its constrictor muscles, the sternothyroid and
remains of sternohyoid muscles, and (2) dissect the muscles of the
larynx (p. 249, and Fig. 105). Dissect all those of one side first. The
mucosa lining the vestibule and middle portions of the laryngeal cavity
must be removed. After studying the muscles, remove the muscles and
entire mucosa by scraping carefully with a dull but smooth scalpel, and
study the cartilages (Fig. 104).
III. The trachea and lungs (p. 251, and Fig. 106). The distal end of the
trachea and lungs may now be removed with the heart from the body. The
lungs may be inflated with the bellows. The bronchi should then be
exposed, cleaned, and followed as far as possible into the lungs. The
heart should be preserved for future study.