The =pulmonary vessels= present no remarkable features.
The =aorta= resembles that of the horse and ox in its course and
relations, but the arch is more strongly curved. There is no common
brachiocephalic trunk (anterior aorta).
The =brachiocephalic artery= arises first from the aortic arch and
passes forward below the trachea to the first rib. Here it gives off the
=common carotid arteries=, and is continued around the first rib as the
right brachial.
The =superior cervical=, =vertebral=, and =dorsal arteries= usually
arise by a common trunk.
The =inferior cervical artery= is large; its ascending branch gives off
the =posterior thyroid artery= and =parotid branches=.
The =internal= and =external thoracic arteries= give branches to the
pectoral mammary glands; the external may be absent.
The =left brachial artery= arises from the aortic arch just above the
brachiocephalic. It curves forward and downward and turns around the
anterior border of the first rib. Its superior cervical, vertebral, and
dorsal branches usually arise separately.
The =carotid arteries= arise from the brachiocephalic close together or
by a very short common trunk. They terminate in occipital and internal
and external carotid divisions.
The =occipital artery= resembles that of the horse.
The =internal carotid artery= usually arises by a common trunk with the
occipital. After giving off a large meningeal branch it passes through
the foramen lacerum and forms with the opposite artery a rete mirabile
which resembles that of the ox, but is smaller and is not connected with
the vertebral and condyloid arteries.
The =external carotid artery= has the same course and termination as in
the horse. Its branches present the following special features: (1) The
=lingual artery= is relatively large and supplies the pharyngeal artery,
the sublingual, muscular branches, and branches to the soft palate,
submaxillary gland, and larynx. (2) The =external maxillary artery= is
small and is distributed chiefly to the submaxillary gland, the
pharyngeal lymph glands, the masseter and the panniculus. It does not
extend upon the lateral surface of the face. (3) The =posterior
auricular artery= is long and relatively large; it gives off the
posterior meningeal.
The =internal maxillary artery= pursues a flexuous course between the
ramus of the mandible and the pterygoid muscles. Its branches offer the
following special features: (1) The =inferior alveolar= (or dental) is
large; branches from it emerge through four or five mental foramina and
take the place of the inferior labial. (2) The =buccinator artery= is
also large and extends to the lips. (3) The =infraorbital artery=
extends to the snout and replaces the superior labial largely and the
lateral nasal in part. The malar branch compensates largely for the
absence of the lateral and dorsal nasal. (4) The =palatine artery= is
small.
The =intercostal arteries= number fourteen to sixteen in either side; of
these ten to twelve arise from the aorta, usually by short common
trunks. Frequently an intercostal artery is given off from that of an
adjacent space.
The =bronchial= and =œsophageal arteries= usually arise separately.
The =cœliac artery= is half an inch to an inch long. It supplies a
branch to the left crus of the diaphragm and divides into two primary
branches, gastro-hepatic and splenic. The =gastro-hepatic artery= is the
larger. It gives off pancreatic branches, the anterior gastric artery,
branches to the lesser curvature of the stomach, pyloric and
gastro-duodenal arteries. The latter divides into pancreatico-duodenal
and right gastro-epiploic. The anterior gastric usually supplies the
œsophageal artery. The continuing trunk (A. hepatica propria) gives off
a cystic branch and divides in the portal fissure into four branches
which supply the liver. The =splenic artery= gives off the posterior
gastric (usually), branches to the stomach above the cardia, twigs to
the pancreas, short gastric arteries to the left part of the great
curvature, and splenic branches, and is continued as the left
gastro-epiploic artery.
The posterior gastric may arise from the gastro-hepatic or in the
angle of divergence of the two primary divisions of the cœliac. The
œsophageal branch may come from the splenic.
[Illustration:
FIG. 480.—ARTERIES OF DISTAL PART OF RIGHT FORE LIMB OF PIG, ANTERIOR
VIEW.
_a_, Terminal part of volar interosseous artery; _b_, dorsal
interosseous artery; _c_, rete carpi dorsale; _d_, dorsal metacarpal
arteries; _e_, dorsal common digital arteries; _f_, dorsal proper
digital arteries.
]
[Illustration:
FIG. 481.—ARTERIES OF DISTAL PART OF RIGHT FORE LIMB OF PIG, POSTERIOR
VIEW.
_g_, Ulnar artery; _h_, superficial branch of radial artery; _i_,
collateral ulnar artery; _j_, volar interosseous artery; _h_, deep
branch of radial artery; _k_, deep volar metacarpal arteries; _l_,
superficial volar metacarpal arteries; _m_, volar common digital
artery; _n_, volar proper digital arteries.
]
The =anterior mesenteric artery= is long like that of the ox. It gives
twigs to the pancreas, the ilio-cæcal and two colic arteries, and is
continued in the mesentery as the artery of the small intestine. This
gives off numerous branches which form a series of arches along the
mesenteric lymph glands. From these is formed a rich network which gives
off innumerable fine branches placed close together. The colic arteries
enter the axis of the spiral coil of the colon and anastomose at its
apex. Their branches also form rich networks.
A =phrenico-abdominal artery= arises on either side a little in front of
the renals. It divides into branches which go to the costal part of the
diaphragm and the abdominal muscles.
The =renal= and =spermatic arteries= present no special characters.
The =posterior mesenteric artery= arises near the termination of the
aorta. It is small and is distributed like that of the ox.
Six pairs of =lumbar arteries= arise from the aorta. The seventh comes
from the middle sacral.
The terminal branches of the aorta resemble those of the ox.
The arteries of the shoulder, arm, and forearm resemble in general those
of the ox.
[Illustration:
FIG. 482.—ARTERIES OF DISTAL PART OF RIGHT HIND LIMB OF PIG, ANTERIOR
VIEW.
_a_, Anterior tibial artery, continued on tarsus as the dorsalis
pedis; _b_, perforating tarsal artery; _c_, dorsal metatarsal
arteries; _d_, common digital arteries; _e_, proper digital
arteries.
]
[Illustration:
FIG. 483.—ARTERIES OF DISTAL PART OF RIGHT HIND LIMB OF PIG, POSTERIOR
VIEW.
_f_, Saphenous artery, continued as internal tarsal artery; _g_,
external tarsal artery; _h_, internal plantar artery; _h′_, external
plantar artery; _i_, perforating tarsal artery; _j_, deep plantar
metatarsal arteries; _k_, common digital artery; _l_, proper digital
arteries.
]
The main facts as to the =metacarpal= and =digital arteries= are as
follows: The rete carpi dorsale is formed essentially by the terminals
of the interosseous artery of the forearm. It gives rise to three
=dorsal metacarpal arteries= which descend in the corresponding
interosseous spaces and unite with branches of the volar metacarpals to
form three =common digital arteries=. Each of these divides into two
=proper digital arteries=, which descend along the interdigital surfaces
of the digits. On the volar surface are two =volar arches=, superficial
and deep, from which three =superficial= and three =deep volar
metacarpal arteries= arise. The deep arteries unite near the distal end
of the space between the principal metacarpal bones to form a stem which
unites with the middle (third) superficial artery. The superficial
arteries unite to form an arch from which =proper digital arteries= are
given off to the axial aspect of the small digits, and a common digital
which supplies two =volar proper digital arteries= to each of the chief
digits.
The arteries of the hip, thigh, and leg are arranged much as in the ox.
A few special features may be noted.
The =ilio-lumbar artery= gives off a branch to the quadriceps femoris.
It may also supply the posterior abdominal artery, which otherwise
arises from the deep femoral.
The =deep femoral artery= is given off above the level of the pubis. The
posterior abdominal and external pudic arteries may arise from it by a
short common trunk or separately. The =external pudic= gives branches to
the prepuce but not to the penis. The =popliteal artery= gives off the
peroneal.
The =femoral artery= gives off a short trunk which divides into anterior
femoral and external circumflex arteries, the latter being much the
larger.
The =saphenous artery= is large. It descends on the inner surface of the
leg and hock and concurs with the perforating tarsal artery in forming
the proximal plantar arch.
The =posterior tibial artery= is small, being replaced distally by the
saphenous. It gives branches to the muscles on the posterior face of the
tibia and supplies the nutrient artery of that bone.
The =anterior tibial artery= is continued as the dorsalis pedis on the
flexion surface of the tarsus. This gives off the =perforating tarsal
artery=, which passes back through the vascular canal of the tarsus and
unites with the terminal branches of the saphenous to form the proximal
plantar arch.
The =metatarsal= and =digital arteries= resemble in arrangement the
corresponding vessels of the fore limb.