_1_, Facial artery; _2_, inferior labial artery; _3_, artery of angle
of mouth; _4_, superior labial artery; _5_, lateral nasal artery;
_6_, dorsal nasal artery; _7_, superficial temporal artery; _8_,
transverse facial artery; _9_, anterior auricular artery; _10_,
zygomatico-orbital artery; _11_, satellite vein of _10_; _12_, ant.
auricular vein; _13_, superficial temporal vein; _14_, internal
maxillary vein; _15_, post. auricular vein; _16_, _17_, external
jugular vein; _18_, external maxillary vein; _19_, _23_, facial
vein; _20_, inf. labial vein; _21_, buccinator vein; _22_, vena
reflexa; _24_, superior labial vein; _25_, vena angularis oculi;
_26_, dorsal nasal vein; _a_, concha; _b_, parotid gland; _c_,
submaxillary gland; _d_, submaxillary lymph glands; _e_,
mylo-hyoideus; _f_, digastricus; _g_, masseter; _h_, zygomaticus;
_i_, scutularis; _k_, temporalis; _l_, orbicularis oculi; _m_,
zygomatic arch; _n_, retractor anguli oris; _o_, buccinator.
(Ellenberger-Baum, Anat. d. Hundes.)
]
The =occipital artery= is small. It gives off =condyloid= and =posterior
meningeal= branches, passes up through the notch on the anterior margin
of the wing of the atlas, and is distributed to the muscles of this
region. Its =cerebrospinal= branch passes through the intervertebral
foramen, and unites in the vertebral canal with its fellow and a branch
from the vertebral artery to form the basilar. A retrograde branch
anastomoses with the vertebral as in the horse.
The =internal carotid artery=, also small, passes to the foramen lacerum
posterius, enters the carotid canal and forms a bend before entering the
cranium through the carotid foramen. It forms a plexus which is
connected by branches with the middle meningeal and ophthalmic arteries.
It then perforates the dura mater and enters into the formation of the
arterial circle (of Willis).
The =external carotid artery= is the direct continuation of the common
carotid. It passes along the lateral wall of the pharynx, emerges from
beneath the digastricus, and divides into superficial temporal and
internal maxillary arteries. It gives off the large flexuous =lingual
artery= which has a course similar to that of the horse. The =external
maxillary=, smaller than the lingual, passes along the upper border of
the digastricus, gives off the sublingual, gains the anterior border of
the masseter, and divides into superior and inferior labial and the
angularis oris. The last-named vessel passes forward on the cheek
between the labials to the angle of the mouth. The =sublingual artery=
passes at first along the upper border of the digastricus and continues
between the mylo-hyoideus and the ramus of the mandible. The =posterior
auricular artery= arises at the anterior border of the digastricus,
gives branches to the salivary glands and the adjacent muscles, and
ascends on the convex face of the concha. It divides into two branches
which return along the borders of the external ear.
The =superficial temporal artery=, after giving off the =anterior
auricular artery= and a small =transverse facial artery=, turns forward
under the temporal fascia toward the eye, and divides into upper and
lower branches which supply the frontal region and the eyelids. It also
supplies branches to the parotid gland and the masseter and temporalis
muscles.
The =internal maxillary artery= pursues a course similar to that of the
horse. The mental branches of the =inferior alveolar= (or dental)
=artery= are of considerable size and are distributed in the lower lip
and gums. Two or three =deep temporal arteries= are present. The
anterior one may arise from the buccinator; it gives off the middle
meningeal, which sends a branch to the carotid plexus. The =ophthalmic
artery= gives off a branch which enters the cranium through the foramen
lacerum orbitale and connects with the internal carotid; this is termed
the internal ophthalmic and gives off the arteria centralis retinæ. The
superficial branches of the =infraorbital artery= replace the dorsal and
lateral nasal arteries, and compensate for the small size of the
superior labial.
The =brachial artery= in its course in the arm presents no special
features. At the elbow it passes between the biceps and the pronator
teres, descends (as the median) under the flexor carpi radialis about a
third of the way down the forearm, and divides into radial and ulnar
arteries. Among its collateral branches are: (1) The =subscapular
artery=, which passes up between the subscapularis and teres major,
turns around the posterior angle of the scapula and terminates in the
supraspinatus, deltoid, trapezius, and mastoido-humeralis. In about half
the cases it gives off the =anterior circumflex=, which often arises
with the =posterior circumflex=. Its other branches resemble those of
the horse. (2) The =anterior circumflex artery= (in about half the
cases). (3) The =deep brachial= arises about a third of the way down the
arm. (4) The =bicipital artery= (for the biceps) is given off at the
lower part of the arm. (5) The =proximal collateral radial artery= (not
present in the horse) arises at the lower fourth of the arm, crosses
over the terminal part of the biceps, descends on the extensor carpi
radialis, and concurs with a branch of the volar interosseous in forming
the rete carpi dorsale. It often supplies the bicipital artery. (6) The
=anterior radial artery= (A. collateralis radialis distalis) is very
small. (7) The =common interosseous artery= is given off a little below
the elbow. It supplies branches to the flexor muscles and the =dorsal
interosseous artery=, which passes through the interosseous space, gives
branches to the extensor muscles, and by its terminal twigs concurs in
the formation of the rete carpi dorsale. The direct continuation of the
trunk is the =volar interosseous artery=, which descends under cover of
the pronator quadratus, gives off a branch to the rete carpi dorsale and
the =fifth volar metacarpal artery=, and terminates by joining the volar
branch of the radial artery to form the deep volar arch. (8) The =volar
antibrachial artery= (Ramus volaris antibrachii) arises below the
interosseous and descends at first under the flexor carpi radialis, then
between the heads of the deep flexor, and divides into ascending and
descending branches.
The =radial artery=, the smaller terminal of the brachial, descends
along the inner border of the radius, and divides near the carpus into
dorsal and volar branches. The =dorsal branch= assists in forming the
rete carpi dorsale. The larger =volar branch= descends behind the inner
border of the carpus and joins the end of the volar interosseous in
forming the =deep volar arch=. From this arch three =deep volar
metacarpal arteries= descend in the second, third, and fourth
intermetacarpal spaces and concur with the corresponding superficial
volar and the dorsal arteries to form the common digitals.
[Illustration:
FIG. 487.—VESSELS AND NERVES OF INNER SURFACE OF SHOULDER AND ARM OF
DOG.
_a_, _b_, Brachial artery; _c_, subscapular vessels; _d_,
thoracico-dorsal vessels; _e_, deep brachial vessels; _f_, superior
collateral ulnar vessels; _g_, brachial vein; _h_, _h″_, cephalic
vein; _h′_, mediano-radial vein; _i_, anterior thoracic nerves; _k_,
musculo-cutaneous nerve; _l_, median nerve; _m_, ulnar nerve; _n_,
radial nerve; _o_, thoracico-dorsal nerve; _1_, subscapularis
muscle; _2_, supraspinatus muscle; _3_, teres major; _4_, latissimus
dorsi; _5_, deep pectoral muscle; _6_, biceps brachii; _7_, long
head of triceps; _8_, tensor fasciæ antibrachii; _9_, internal head
of triceps; _10_, pronator teres. (Ellenberger-Baum, Anat. d.
Hundes.)
]
[Illustration: