From photograph of specimen hardened _in situ_. Dotted line indicates
position of spleen.
]
The =salivary glands= resemble those of the ox in general, but the
parotid duct crosses the surface of the masseter muscle, and opens
opposite the third or fourth cheek tooth.
The =tonsil= is bean-shaped and about half an inch (ca. 12 mm.) in
length. It does not project into the fauces. The mucous membrane of the
latter presents two deep and very narrow tonsillar sinuses on either
side.
[Illustration:
FIG. 303.—CROSS-SECTION OF SHEEP, THROUGH NINTH THORACIC VERTEBRA,
ANTERIOR VIEW.
_1_, Cardiac orifice; _2_, œsophageal groove; _3_, rumino-reticular
orifice; _4_, rumino-reticular fold; _5_, dorsal sac of rumen; _6_,
body of ninth thoracic vertebra; _7_, vena hemiazygos; _8_, aorta;
_9_, posterior mediastinal lymph gland; _10_, _10_, crura of
diaphragm; _11_, posterior vena cava; _12_, portal vein; _R.l._,
right lung; _L.l._, left lung; _S_, spleen (cut very obliquely);
_L_, liver; _R_, reticulum (posterior wall). Arrow points to
reticulo-omasal orifice.
]
The fornix of the =pharynx= presents a median plicated fold which is a
continuation of the septum nasi. The pharyngeal orifice of the
Eustachian tube has the form of a crescentic slit, placed about on a
level with the inferior nasal meatus. There are two large lymph glands
and a number of hæmolymph glands above the pharynx.
The =œsophagus= has a lumen of about an inch when moderately distended;
otherwise it resembles that of the ox.
[Illustration:
FIG. 304.—ABDOMINAL VISCERA OF SHEEP, SUPERFICIAL VENTRAL VIEW.
]
The =stomach= is like that of the ox in its general arrangement. Its
average capacity is about four gallons (ca. 15 liters). The =cardiac
opening= is opposite the middle of the eighth intercostal space; it is
just to the left of the median plane and about two to three inches (ca.
5 to 7 cm.) below the vertebral column. The ventral sac of the =rumen=
is relatively larger and extends further to the right of the median
plane than in the ox. There are no coronary pillars in the dorsal sac,
but its upper part is papillated. The papillæ of the rumen are
relatively =large= and somewhat tongue-like; the largest are about a
fourth of an inch (ca. 6 mm.) in length. The =reticulum= is relatively
larger than in the ox. Its ventral part curves more backward and less to
the right than in the ox. The parietal surface extends forward as far as
the sixth rib or intercostal space, and is related to the diaphragm and
liver. The fundus lies on the sternal part of the diaphragm and in
contact with the abomasum. The =œsophageal groove= is disposed much like
that of the ox, and is about four to five inches (ca. 8 to 10 cm.) long.
The =omasum= is much smaller than the reticulum, its capacity being only
about one pint. It is oval and compressed laterally. It is situated
almost entirely to the right of the median plane, opposite to the ninth
and tenth ribs, higher than in the ox, and has no contact with the
abdominal wall. It is related on the right to the liver and
gall-bladder, on the left to the rumen, and below to the abomasum. The
laminæ are less numerous than in the ox; in the neck which connects the
omasum with the reticulum they have the form of low thick ridges, and
bear long, pointed, horny papillæ. The =abomasum= is relatively larger
and longer than in the ox. Its capacity is about twice that of the
reticulum and averages about two quarts (ca. 1.75 to 2 liters). The
blind anterior end lies almost centrally in the xiphoid region, in
relation to the liver and reticulum. Its body extends backward a little
below and almost parallel with the right costal arch. The pylorus is
opposite the ventral end of the eleventh or twelfth intercostal space.
The cells of the reticulum are much shallower than in the ox. At the
reticulo-omasal opening and on the adjacent part of the laminæ of the
omasum are large, pointed, horny papillæ. The number of laminæ is less
than in the ox.
The general arrangement of the =intestine= is like that of the ox. The
=small intestine= is about 80 feet (ca. 24 to 25 m.) long; its average
diameter is about an inch (ca. 2 to 3 cm.), the caliber increasing in
its terminal part, where a very extensive Peyer’s patch is found. The
=cæcum= is about 10 to 12 inches (ca. 25 to 30 cm.) long, 2 inches (ca.
5 cm.) wide, and has a capacity of about a quart (ca. 1 liter). The
=colon= is about 15 feet (ca. 4 to 5 m.) long. Its caliber is at first
about the same as that of the cæcum, but diminishes to about the width
of the small intestine.
[Illustration:
FIG. 305.—LIVER OF SHEEP, VISCERAL SURFACE; HARDENED _in situ_.
]
The =liver= weighs about 20 to 25 ounces (ca. 550 to 700 gm.). It lies
entirely to the right of the median plane. The parietal surface is
related almost exclusively to the right part of the diaphragm. The
visceral surface presents extensive reticular and abomasal impressions,
and a small omasal impression internal to the portal fissure. The
umbilical fissure is deep and partially divides the gland into two chief
lobes. The caudate lobe is prismatic and blunt-pointed. The neck of the
gall-bladder is long. The bile-duct joins the pancreatic duct to form a
=common duct= (Ductus choledochus communis) which opens into the
duodenum about one foot (ca. 30 cm.) from the pylorus.
The =pancreas= is arranged as in the ox. Its duct unites with the
bile-duct.
The =spleen= (Fig. 301) is somewhat triangular, with the angles rounded
off. It weighs about three or four ounces (ca. 100 grams). Its length is
about five inches (ca. 12 to 13 cm.) and its greatest width about four
inches (ca. 10 cm.). The parietal surface is convex and is related to
the diaphragm, to which rather more than the anterior third is adherent.
The visceral surface is concave and its anterior half is attached to the
dorsal curvature of the rumen. The dorsal end or base is attached to the
left crus of the diaphragm under the last two or three ribs. The hilus
is at the posterior basal angle. The ventral end is narrower and thinner
than the base; it is situated opposite the ninth and tenth ribs above
their middles.
[Illustration:
FIG. 306.—LIVER OF SHEEP, PARIETAL SURFACE; HARDENED _in situ_.
]