LESSON 17
Arterial system
Systemic and
pulmonary arteries
THE BLOOD VESSELS
You already know that the cardiovascular system is
divided into the pulmonary circuit and the systemic circuit. The
pulmonary circuit is composed of arteries and veins that transport blood
between the heart and the lungs. This circuit begins at the right ventricle and
ends at the left atrium. From the left ventricle, the arteries of the systemic
circuit transport oxygenated blood and nutrients to all organs and tissues,
ultimately returning deoxygenated blood to the right atrium. Figure 21-20;){kind=small}
summarizes the primary circulatory routes within the
pulmonary and systemic circuits.
In the pages that follow, we shall examine the vessels
of the pulmonary and systemic circuits in detail. Two general functional
patterns are worth noting at the outset:
- The peripheral
distributions of arteries and veins on the left and right sides are
generally identical except near the heart, where the largest vessels
connect to the atria or ventricles. For example, there are left and
right subclavian, axillary, brachial, and radial arteries
whose distribution parallels that of the left and right
subclavian, axillary, brachial, and radial veins, respectively.
- A single vessel may have
several different names as it crosses specific anatomical boundaries,
making accurate anatomical descriptions possible when the vessel extends
far into the periphery. For example, the external iliac artery
becomes the femoral artery as it leaves the trunk and enters the
lower limb.
The Pulmonary Circulation
Blood entering the right atrium has just returned from
the peripheral capillary beds, where oxygen was released and carbon dioxide was
absorbed. After traveling through the right atrium and ventricle, blood enters
the pulmonary trunk, the start of the pulmonary circuit (Figure 21-21;){kind=small}
). At the lungs, oxygen will be replenished, carbon
dioxide will be released, and the oxygenated blood will be returned to the
heart for distribution via the systemic circuit. Compared with the systemic
circuit, the pulmonary circuit is relatively short: The base of the pulmonary
trunk and the lungs are only about
The arteries of the pulmonary circuit differ from those
of the systemic circuit in that they carry deoxygenated blood. (For this
reason, most color-coded diagrams show the pulmonary arteries in blue, the same
color as systemic veins.) As it curves over the superior border of the heart,
the pulmonary trunk gives rise to the left and right pulmonary arteries. These
large arteries enter the lungs before branching repeatedly, giving rise to
smaller and smaller arteries. The smallest branches, the pulmonary
arterioles, provide blood to capillary networks that surround alveoli.
The walls of these small air pockets are thin enough for gas exchange to occur
between the capillary blood and inspired air. As it leaves the alveolar
capillaries, oxygenated blood enters venules that in turn unite to form larger
vessels carrying blood toward the pulmonary veins. These four veins, two from
each lung, empty into the left atrium, completing the pulmonary circuit.
The Systemic Circulation
The systemic circulation supplies the capillary beds
in all parts of the body not serviced by the pulmonary circuit. The systemic
circuit, which at any given moment contains about 84 percent of the total blood
volume, begins at the left ventricle and ends at the right atrium.
Systemic Arteries
Figure 21-22;){kind=small}
is an overview of the systemic arterial system. This
figure indicates the relative locations of major systemic arteries.
The Ascending Aorta
The ascending aorta begins at the aortic semilunar valve of the left ventricle
(Figure 21-23;){kind=small}
;){kind=small}
). The left and right coronary arteries originate at the
base of the ascending aorta, just superior to the aortic semilunar valve. We
detailed the distribution of coronary vessels in Chapter 20 and illustrated
them in Figure 20-8.
The Aortic Arch
The aortic arch curves like a cane handle across the superior surface of the
heart, connecting the ascending aorta with the descending aorta. Three
elastic arteries originate along the aortic arch (Figures 21-22, 21-23, and 21-24;){kind=small}
). These arteries, (1) the brachiocephalic, (2) the
left common carotid, and (3) the left subclavian, deliver blood to the head, neck, shoulders, and
upper limbs. The brachiocephalic artery, also called the innominate artery
(unnamed), ascends for a short distance before branching to form the right
subclavian artery and the right common carotid artery.
There is only one brachiocephalic artery, and the left
common carotid and left subclavian arteries arise separately from the aortic
arch. However, in terms of their peripheral distribution, the vessels on the
left side are mirror images of those on the right side. Because the
descriptions that follow focus on major branches found on both sides of the
body, for clarity we will not use the terms right and left in the
following discussion. Figures 21-23 and 21-24 illustrate the major branches of these arteries.
The Subclavian Arteries. The subclavian arteries supply blood to the arms,
chest wall, shoulders, back, and CNS (Figures 21-22 and 21-23). Three major branches arise before a subclavian
artery leaves the thoracic cavity: (1) the thyrocervical artery, which provides
blood to muscles and other tissues of the neck, shoulder, and upper back; (2)
the internal thoracic artery, supplying the pericardium and anterior wall of
the chest; and (3) the vertebral artery, which provides blood to the brain and
spinal cord.
After leaving the thoracic cavity and passing across
the superior border of the first rib, the subclavian is called the axillary
artery. The axillary artery crosses the axilla to enter the arm, where it
becomes the brachial artery. The brachial artery supplies blood to the upper
extremity. At the antecubital fossa, the brachial artery divides into the
radial artery, which follows the radius, and the ulnar artery, which follows
the ulna to the wrist. These arteries supply blood to the forearm. At the
wrist, they anastomose to form the superficial palmar arch and the deep palmar
arch, which supply blood to the hand and to the digital arteries of the thumb
and fingers.
The Carotid Artery and the Blood Supply to the Brain. The common carotid arteries ascend deep in the tissues
of the neck. You can usually locate the carotid artery by pressing gently along
either side of the windpipe (trachea) until you feel a strong pulse.
Each common carotid artery divides into an external
carotid and an internal carotid
artery (Figure 21-24). The carotid sinus, located at the base of the
internal carotid, may extend along a portion of the common carotid. The
external carotids supply blood to the structures of the neck, esophagus,
pharynx, larynx, lower jaw, and face. The internal carotids enter the skull
through the carotid canals of the temporal bones, delivering blood to
the brain (see Figures 7-3e;){kind=small}
and 7-4b;){kind=small}
).
The internal carotids ascend to the level of the optic
nerves, where each divides into three branches: (1) an ophthalmic artery, which
supplies the eyes; (2) an anterior cerebral artery, which supplies the frontal
and parietal lobes of the brain; and (3) a middle cerebral artery, which
supplies the mesencephalon and lateral surfaces of the cerebral hemispheres
(Figures 21-24 and 21-25;){kind=small}
;){kind=small}
).
The brain is extremely sensitive to changes in its
circulatory supply. An interruption of circulation for several seconds will
produce unconsciousness, and after 4 minutes there may be some permanent neural
damage. Such circulatory crises are rare, because blood reaches the brain
through the vertebral arteries as well as by way of the internal carotids. The
left and right vertebral arteries arise from the subclavian arteries and ascend
within the transverse foramina of the cervical vertebrae. The vertebral
arteries enter the cranium at the foramen magnum, where they fuse along the
ventral surface of the medulla oblongata to form the basilar artery. The
basilar artery continues on the ventral surface along the pons, branching many
times before dividing into the posterior cerebral arteries. The posterior communicating
arteries branch off the posterior cerebral arteries (Figure 21-25).
The internal carotids normally supply the arteries of
the anterior half of the cerebrum, and the rest of the brain receives blood
from the vertebral arteries. But this circulatory pattern can easily change,
because the internal carotids and the basilar artery are interconnected in a
ring-shaped anastomosis called the cerebral arterial circle, or circle of
Willis, which encircles the infundibulum of the pituitary gland (Figure
21-25). With this arrangement, the brain can receive blood
from either the carotids or the vertebrals, and the chances for a serious interruption
of circulation are reduced.
Common carotid artery. Vascular nervous bundle of the
neck
Brachiocephalic
trunk begins from aortic arch on level of right II costal
cartilage. It passes upward and to the right of and on level of right
sternо-clavicular joint divides into two terminal branches - right common
carotid and right subclavianу arteries.
Brachiocephalic trunk is the largest branch of the arch of the aorta, and is from 4 to
The arch of the aorta, and its branches.
Relations.—Anteriorly, it
is separated from the manubrium sterni by the Sternohyoideus and Sternothyreoideus,
the remains of the thymus, the left innominate and right inferior thyroid veins
which cross its root, and sometimes the superior cardiac branches of the right
vagus. Posterior to it is the trachea, which it crosses obliquely. On
the right side are the right innominate vein, the superior vena cava,
the right phrenic nerve, and the pleura; and on the left side, the
remains of the thymus, the origin of the left common carotid artery, the
inferior thyroid veins, and the trachea.
Branches.—The brachiocephalic trunk usually
gives off no branches; but occasionally a small branch, the thyreoidea ima,
arises from it. Sometimes it gives off a thymic or bronchial branch.
The thyreoidea ima (a. thyreoidea ima) ascends
in front of the trachea to the lower part of the thyroid gland, which it
supplies. It varies greatly in size, and appears to compensate for deficiency
or absence of one of the other thyroid vessels. It occasionally arises from the
aorta, the right common carotid, the subclavian or the internal mammary.
Point of Division.—The brachiocephalic
trunk sometimes divides above the level of the sternoclavicular joint, less
frequently below it.
Position.—When the aortic arch is on the right side, the
innominate is directed to the left side of the neck.
Superficial dissection of the right side of the neck, showing the
carotid and subclavian arteries.
Collateral Circulation.—Allan Burns demonstrated, on the dead
subject, the possibility of the establishment of the collateral circulation
after ligature of the brachiocephalic trunk, by tying and dividing that artery.
He then found that “Even coarse injection, impelled into the aorta, passed
freely by the anastomosing branches into the arteries of the right arm, filling
them and all the vessels of the head completely.” 97 The branches by which
this circulation would be carried on are very numerous; thus, all the
communications across the middle line between the branches of the carotid
arteries of opposite sides would be available for the supply of blood to the
right side of the head and neck; while the anastomosis between the
costocervical of the subclavian and the first aortic intercostal (see infra
on the collateral circulation after obliteration of the thoracic aorta) would
bring the blood, by a free and direct course, into the right subclavian. The
numerous connections, also, between the intercostal arteries and the branches of
the axillary and internal mammary arteries would, doubtless, assist in the
supply of blood to the right arm, while the inferior epigastric from the
external iliac would, by means of its anastomosis with the internal mammary,
compensate for any deficiency in the vascularity of the wall of the chest.
Common
carotid artery passes behind sternocleidomastoid
muscle upward on front of transverse processes of cervical vertebrae and does
not give off any branches. On the level of upper edge of thyroid cartilage common
carotid artery divides into external carotid artery and internal carotid
artery. This place called bifurcation of carotid artery. There are carotid
sinus and carotid glomus here.
The Arteries of the Head and Neck.
The principal arteries of supply to the head and neck are the two common
carotids; they ascend in the neck and each divides into two branches, viz.,
(1) the external carotid, supplying the exterior of the head, the face,
and the greater part of the neck; (2) the internal carotid, supplying to
a great extent the parts within the cranial and orbital cavities.
The Common Carotid Artery (A. Carotis Communis)—The common carotid arteries differ in length and in their mode
of origin. The right begins at the bifurcation of the brachiocephalic
trunk behind the sternoclavicular joint and is confined to the neck. The left
springs from the highest part of the arch of the aorta to the left of, and on a
plane posterior to the brachiocephalic trunk, and therefore consists of a
thoracic and a cervical portion.
The thoracic portion of the left common carotid artery
ascends from the arch of the aorta through the superior mediastinum to the
level of the left sternoclavicular joint, where it is continuous with the
cervical portion.
1. Relations.—In front, it is
separated from the manubrium sterni by the Sternohyoideus and
Sternothyreoideus, the anterior portions of the left pleura and lung, the left
innominate vein, and the remains of the thymus; behind, it lies on the
trachea, esophagus, left recurrent nerve, and thoracic duct. To its right
side below is the brachiocephalic trunk, and above, the trachea, the
inferior thyroid veins, and the remains of the thymus; to its left side
are the left vagus and phrenic nerves, left pleura, and lung. The left
subclavian artery is posterior and slightly lateral to it.
The cervical portions of the common carotids resemble
each other so closely that one description will apply to both (507). Each vessel passes
obliquely upward, from behind the sternoclavicular articulation, to the level
of the upper border of the thyroid cartilage, where it divides into the
external and internal carotid arteries.
The arteries of the face and scalp.
At the lower part of the neck the two common carotid
arteries are separated from each other by a very narrow interval which contains
the trachea; but at the upper part, the thyroid gland, the larynx and pharynx
project forward between the two vessels. The common carotid artery is contained
in a sheath, which is derived from the deep cervical fascia and encloses also
the internal jugular vein and vagus nerve, the vein lying lateral to the
artery, and the nerve between the artery and vein, on a plane posterior to
both. On opening the sheath, each of these three structures is seen to have a
separate fibrous investment.
Relations.—At the lower part of
the neck the common carotid artery is very deeply seated, being covered by
the integument, superficial fascia, Platysma, and deep cervical fascia, the Sternocleidomastoideus,
Sternohyoideus, Sternothyreoideus, and Omohyoideus; in the upper part of its
course it is more superficial, being covered merely by the integument, the
superficial fascia, Platysma, deep cervical fascia, and medial margin of the Sternocleidomastoideus.
When the latter muscle is drawn backward, the artery is seen to be contained in
a triangular space, the carotid triangle, bounded behind by the
Sternocleidomastoideus, above by the Stylohyoideus and posterior belly of the
Digastricus, and below by the superior belly of the Omohyoideus. This part of
the artery is crossed obliquely, from its medial to its lateral side, by the
sternocleidomastoid branch of the superior thyroid artery; it is also crossed
by the superior and middle thyroid veins which end in the internal jugular;
descending in front of its sheath is the descending branch of the hypoglossal
nerve, this filament being joined by one or two branches from the cervical
nerves, which cross the vessel obliquely. Sometimes the descending branch of
the hypoglossal nerve is contained within the sheath. The superior thyroid vein
crosses the artery near its termination, and the middle thyroid vein a little
below the level of the cricoid cartilage; the anterior jugular vein crosses the
artery just above the clavicle, but is separated from it by the Sternohyoideus
and Sternothyreoideus. Behind, the artery is separated from the
transverse processes of the cervical vertebræ by the Longus colli and
Longus capitis, the sympathetic trunk being interposed between it and the
muscles. The inferior thyroid artery crosses behind the lower part of the
vessel. Medially, it is in relation with the esophagus, trachea, and
thyroid gland (which overlaps it), the inferior thyroid artery and recurrent
nerve being interposed; higher up, with the larynx and pharynx. Lateral
to the artery are the internal jugular vein and vagus nerve.
At the lower part of the neck, the right recurrent nerve
crosses obliquely behind the artery; the right internal jugular vein diverges
from the artery, but the left approaches and often overlaps the lower part of
the artery.
Behind the angle of bifurcation of the common carotid artery
is a reddish-brown oval body, known as the glomus caroticum (carotid
body). It is similar in structure to the glomus coccygeum (coccygeal
body) which is situated on the middle sacral artery.
Peculiarities as to Origin.—The right
common carotid may arise above the level of the upper border of the
sternoclavicular articulation; this variation occurs in about 12 per cent. of
cases. In other cases the artery may arise as a separate branch from the arch
of the aorta, or in conjunction with the left carotid. The left common
carotid varies in its origin more than the right. In the majority of
abnormal cases it arises with the brachiocephalic trunk; if that artery is
absent, the two carotids arise usually by a single trunk. It is rarely joined
with the left subclavian, except in cases of transposition of the aortic arch.
Peculiarities as to Point of Division.—In
the majority of abnormal cases this occurs higher than usual, the artery
dividing opposite or even above the hyoid bone; more rarely, it occurs below,
opposite the middle of the larynx, or the lower border of the cricoid
cartilage; one case is related by Morgagni, where the artery was only
Occasional Branches.—The common carotid
usually gives off no branch previous to its bifurcation, but it occasionally
gives origin to the superior thyroid or its laryngeal branch, the ascending
pharyngeal, the inferior thyroid, or, more rarely, the vertebral artery.
Collateral Circulation.—After ligature
of the common carotid, the collateral circulation can be perfectly established,
by the free communication which exists between the carotid arteries of opposite
sides, both without and within the cranium, and by enlargement of the branches
of the subclavian artery on the side corresponding to that on which the vessel
has been tied. The chief communications outside the skull take place between
the superior and inferior thyroid arteries, and the profunda cervicis and ramus
descendens of the occipital; the vertebral takes the place of the internal
carotid within the cranium.
External carotid artery (neck branches)
External carotid artery
starts from common carotid artery in carotid triangle on level of superior
margin of thyroid cartilage. On level of mandibular neck this artery divides by
its two terminal branches. On its extent external carotid artery gives off
branches of anterior, posterior, medial and terminal groups.
Follow arteries belong to anterior
group:
1.
superior thyroid artery
supplies thyroid gland and gives off a superior laryngeal artery, which
supplies muscles and mucous membrane of the larynx;
2.
lingual artery
supplies sublingual salivary gland and gives off dorsal branches and deep
lingual artery, which supplies muscles and mucous membrane of the tongue;
3.
facial artery
in submandibular triangle gives off the branches to submandibular salivary
glands, ascending palatine artery to velum and tonsillar branch
to palatine tonsils. Bending over margin of mandible in front of masseter
muscle, it gives off on face superior labial artery and inferior
labial artery. By terminal branch of facial artery is anglular artery,
which passes to medial eye angle and anastomoses with dorsal nasal artery
from system of internal carotid artery (ophtalmic artery).
Posterior group includes :
1.
sternocleidomastoid
branch passes to same named muscle and can start from superior thyroid artery,
or from occipital artery;
2.
occipital artery supplies
posterior skin occipital region;
3.
posterior auricular artery
supplies outer and middle ear (by posterior tympanic artery).
Ascending pharyngel artery
belong to medial group. It supplies
pharynx, deep neck muscles, cerebral dura mater (posterior meningeal artery
and tympanic cavity (by inferior tympanic artery through fossula
petrosa).
Follow arteries belong to terminal
branches:
1)
Superficial temporal artery,
which is continuation of external carotid artery, passes in front of auricle
into temporal area and on level of supraorbital margin of frontal bone
subdivides into frontal branch and parietal branch, which feed
muscles and skin in frontal and parietal area. On this course superficial
temporal artery gives off the branches for parotid salivary gland (r.
parotideus), zygomaticoorbital artery, for facial muscles (a. transversa
faciei), for auricle (rr. auriculares anteriores) and for temporal
muscle (a. temporalis media);
2)
Maxillary artery
is a largest branch of external carotid artery. According to topography in it
one can pick out a mandibular portion, pterygoid portion and pterygopalatine
portion.
a)
The first mandibular portion
gives off branches to temporo-mandibular joint
The internal carotid and vertebral arteries. Right side.
b)
·
deep auricular artery supplies
external ear also tympanic membrane
·
anterior tympanic artery
supplies the tympanic cavity
·
middle meningeal artery
passes through spinous foramen into scull and feeds dura mater
·
inferior alveolar artery
runs into mandibular canal supplies teeth and gingivae of lower
jaw and continue as mental artery in mental region.
b)
The second portion of maxillary
artery gives off the branches to masticator and buccal muscles (masseteric,
deep temporal arteries, pterygoid branches, and buccal artery).
c)
The third portion of maxillary
artery gives off :
·
Posterior superior alveolar arteries
pass though alveolar canals of maxilla, supply teeth of upper jaw: molars and
premolars with parodont
·
infraorbital artery
runs through inferior orbital fissura and infraorbital canal, gives off anterior
and middle superior alveolar arteries that supply maxilla, upper
teeth and gingivae, face muscles
·
sphenopalatine artery
to mucous membrane of the nasal cavity
·
descending palatine artery
(for palatine)
·
major and minores palatine arteries
(for palatine)
The external carotid artery begins opposite the upper border of
the thyroid cartilage, and, taking a slightly curved course, passes upward and
forward, and then inclines backward to the space behind the neck of the mandible,
where it divides into the superficial temporal and internal maxillary arteries.
It rapidly diminishes in size in its course up the neck, owing to the number
and large size of the branches given off from it. In the child, it is somewhat
smaller than the internal carotid; but in the adult, the two vessels are of
nearly equal size. At its origin, this artery is more superficial, and placed
nearer the middle line than the internal carotid, and is contained within the
carotid triangle.
Relations.—The external carotid
artery is covered by the skin, superficial fascia, Platysma, deep
fascia, and anterior margin of the Sternocleidomastoideus; it is crossed by the
hypoglossal nerve, by the lingual, ranine, common facial, and superior thyroid
veins; and by the Digastricus and Stylohyoideus; higher up it passes deeply
into the substance of the parotid gland, where it lies deep to the facial nerve
and the junction of the temporal and internal maxillary veins. Medial to
it are the hyoid bone, the wall of the pharynx, the superior laryngeal nerve,
and a portion of the parotid gland. Lateral to it, in the lower part of
its course, is the internal carotid artery. Posterior to it, near its
origin, is the superior laryngeal nerve; and higher up, it is separated from
the internal carotid by the Styloglossus and Stylopharyngeus, the
glossopharyngeal nerve, the pharyngeal branch of the vagus, and part of the
parotid gland.
Branches.—The branches of the external carotid artery may
be divided into four sets.
Anterior.
Posterior.
Ascending.
Terminal.
Superior Thyroid.
Occipital.
Ascending
Superficial Temporal.
Lingual.
Posterior Auricular.
Pharyngeal.
Maxillary.
1. The superior thyroid artery (a. thyreoidea
superior) (507) arises from the external carotid artery
just below the level of the greater cornu of the hyoid bone and ends in the
thyroid gland.
Relations.—From its origin under the anterior border of the
Sternocleidomastoideus it runs upward and forward for a short distance in the
carotid triangle, where it is covered by the skin, Platysma, and fascia; it
then arches downward beneath the Omohyoideus, Sternohyoideus, and
Sternothyreoideus. To its medial side are the Constrictor pharyngis inferior
and the external branch of the superior laryngeal nerve.
Branches.—It distributes twigs to the
adjacent muscles, and numerous branches to the thyroid gland, anastomosing with
its fellow of the opposite side, and with the inferior thyroid arteries. The
branches to the gland are generally two in number; one, the larger, supplies
principally the anterior surface; on the isthmus of the gland it anastomoses
with the corresponding artery of the opposite side: a second branch descends on
the posterior surface of the gland and anastomoses with the inferior thyroid
artery.
Besides the arteries distributed to the muscles and to the
thyroid gland, the branches of the superior thyroid are:
Hyoid.
Superior Laryngeal.
Sternocleidomastoid.
Cricothyroid.
The Hyoid Branch (ramus hyoideus; infrahyoid
branch) is small and runs along the lower border of the hyoid bone beneath
the Thyreohyoideus and anastomoses with the vessel of the opposite side.
The Sternocleidomastoid Branch (ramus
sternocleidomastoideus; sternomastoid branch) runs downward and lateralward
across the sheath of the common carotid artery, and supplies the
Sternocleidomastoideus and neighboring muscles and integument; it frequently arises
as a separate branch from the external carotid.
The Superior Laryngeal Artery (a. laryngea
superior), larger than either of the preceding, accompanies the internal
laryngeal branch of the superior laryngeal nerve, beneath the Thyreohyoideus;
it pierces the hyothyroid membrane, and supplies the muscles, mucous membrane,
and glands of the larynx, anastomosing with the branch from the opposite side.
The Cricothyroid Branch (ramus cricothyreoideus)
is small and runs transversely across the cricothyroid membrane, communicating
with the artery of the opposite side.
2. The lingual artery (a. lingualis) (513) arises from the external carotid between
the superior thyroid and external maxillary; it first runs obliquely upward and
medialward to the greater cornu of the hyoid bone; it then curves downward and
forward, forming a loop which is crossed by the hypoglossal nerve, and passing
beneath the Digastricus and Stylohyoideus it runs horizontally forward, beneath
the Hyoglossus, and finally, ascending almost perpendicularly to the tongue, turns
forward on its lower surface as far as the tip, under the name of the profunda
linguæ.
Relations.—Its first, or oblique,
portion is superficial, and is contained within the carotid triangle; it rests
upon the Constrictor pharyngis medius, and is covered by the Platysma and the
fascia of the neck. Its second, or curved, portion also lies upon the
Constrictor pharyngis medius, being covered at first by the tendon of the
Digastricus and by the Stylohyoideus, and afterward by the Hyoglossus. Its
third, or horizontal, portion lies between the Hyoglossus and Genioglossus. The
fourth, or terminal part, under the name of the profunda linguæ (ranine
artery) runs along the under surface of the tongue to its tip; here it is
superficial, being covered only by the mucous membrane; above it is the
Longitudinalis inferior, and on the medial side the Genioglossus. The
hypoglossal nerve crosses the first part of the lingual artery, but is
separated from the second part by the Hyoglossus.
Branches.—The branches of the lingual artery
are:
Hyoid.
Sublingual.
Dorsales linguæ.
Profunda linguæ.
The Hyoid Branch (ramus
hyoideus; suprahyoid branch) runs along the upper border of the hyoid bone,
supplying the muscles attached to it and anastomosing with its fellow of the
opposite side.
The Arteriæ Dorsales Linguæ (rami
dorsales linguæ) consist usually of two or three small branches which
arise beneath the Hyoglossus; they ascend to the back part of the dorsum
of the tongue, and supply the mucous membrane in this situation, the
glossopalatine arch, the tonsil, soft palate, and epiglottis; anastomosing with
the vessels of the opposite side.
The Sublingual Artery (a. sublingualis) arises
at the anterior margin of the Hyoglossus, and runs forward between the
Genioglossus and Mylohyoideus to the sublingual gland. It supplies the gland
and gives branches to the Mylohyoideus and neighboring muscles, and to the
mucous membrane of the mouth and gums. One branch runs behind the alveolar
process of the mandible in the substance of the gum to anastomose with a
similar artery from the other side; another pierces the Mylohyoideus and
anastomoses with the submental branch of the external maxillary artery.
The Arteria Profunda Linguæ (ranine artery;
deep lingual artery) is the terminal portion of the lingual artery; it
pursues a tortuous course and runs along the under surface of the tongue, below
the Longitudinalis inferior, and above the mucous membrane; it lies on the
lateral side of the Genioglossus, accompanied by the lingual nerve. At the tip
of the tongue, it is said to anastomose with the artery of the opposite side,
but this is denied by Hyrtl. In the mouth, these vessels are placed one on
either side of the frenulum linguæ.
3. The facial artery (a. maxillaris externa;
facial artery) (508), arises in the carotid triangle a little
above the lingual artery and, sheltered by the ramus of the mandible, passes
obliquely up beneath the Digastricus and Stylohyoideus, over which it arches to
enter a groove on the posterior surface of the submaxillary gland. It then
curves upward over the body of the mandible at the antero-inferior angle of the
Masseter; passes forward and upward across the cheek to the angle of the mouth,
then ascends along the side of the nose, and ends at the medial commissure of
the eye, under the name of the angular artery. This vessel, both in the
neck and on the face, is remarkably tortuous: in the former situation, to
accommodate itself to the movements of the pharynx in deglutition; and in the
latter, to the movements of the mandible, lips, and cheeks.
Relations.—In the neck,
its origin is superficial, being covered by the integument, Platysma, and
fascia; it then passes beneath the Digastricus and Stylohyoideus muscles and
part of the submaxillary gland, and frequently beneath the hypoglossal nerve.
It lies upon the Constrictores pharyngis medius and superior, the latter of
which separates it, at the summit of its arch, from the lower and back part of
the tonsil. On the face, where it passes over the body of the mandible,
it is comparatively superficial, lying immediately beneath the Platysma. In its
course over the face, it is covered by the integument, the fat of the cheek,
and, near the angle of the mouth, by the Platysma, Risorius, and Zygomaticus.
It rests on the Buccinator and Caninus, and passes either over or under the
infraorbital head of the Quadratus labii superioris. The anterior facial vein
lies lateral to the artery, and takes a more direct course across the face,
where it is separated from the artery by a considerable interval. In the neck
it lies superficial to the artery. The branches of the facial nerve cross the
artery from behind forward.
The arteries of the face and scalp.
Branches.—The branches of the artery may be
divided into two sets: those given off in the neck (cervical), and those
on the face (facial).
Cervical Branches.
Facial Branches.
Ascending Palatine.
Inferior Labial.
Tonsillar.
Superior Labial.
Glandular.
Lateral Nasal.
Submental.
Angular.
Muscular.
Muscular.
The Ascending Palatine Artery (a. palatina
ascendens) (513) arises close to the origin of the
external maxillary artery and passes up between the Styloglossus and
Stylopharyngeus to the side of the pharynx, along which it is continued between
the Constrictor pharyngis superior and the Pterygoideus internus to near the
base of the skull. It divides near the Levator veli palatini into two branches:
one follows the course of this muscle, and, winding over the upper border of
the Constrictor pharyngis superior, supplies the soft palate and the palatine
glands, anastomosing with its fellow of the opposite side and with the
descending palatine branch of the internal maxillary artery; the other pierces
the Constrictor pharyngis superior and supplies the palatine tonsil and
auditory tube, anastomosing with the tonsillar and ascending pharyngeal
arteries.
The internal carotid and vertebral arteries. Right side.
The Tonsillar Branch (ramus tonsillaris) (513) ascends between the
Pterygoideus internus and Styloglossus, and then along the side of the pharynx,
perforating the Constrictor pharyngis superior, to ramify in the substance of
the palatine tonsil and root of the tongue.
The Glandular Branches (rami glandulares;
submaxillary branches) consist of three or four large vessels, which supply
the submaxillary gland, some being prolonged to the neighboring muscles, lymph
glands, and integument.
The Submental Artery (a. submentalis) the
largest of the cervical branches, is given off from the facial artery just as
that vessel quits the submaxillary gland: it runs forward upon the
Mylohyoideus, just below the body of the mandible, and beneath the Digastricus.
It supplies the surrounding muscles, and anastomoses with the sublingual artery
and with the mylohyoid branch of the inferior alveolar; at the symphysis menti
it turns upward over the border of the mandible and divides into a superficial
and a deep branch. The superficial branch passes between the integument and
Quadratus labii inferioris, and anastomoses with the inferior labial artery;
the deep branch runs between the muscle and the bone, supplies the lip, and
anastomoses with the inferior labial and mental arteries.
The Inferior Labial Artery (a. labialis inferior;
inferior coronary artery) arises near the angle of the mouth; it
passes upward and forward beneath the Triangularis and, penetrating the
Orbicularis oris, runs in a tortuous course along the edge of the lower lip
between this muscle and the mucous membrane. It supplies the labial glands, the
mucous membrane, and the muscles of the lower lip; and anastomoses with the
artery of the opposite side, and with the mental branch of the inferior
alveolar artery.
The Superior Labial Artery (a. labialis superior;
superior coronary artery) is larger and more tortuous than the inferior. It
follows a similar course along the edge of the upper lip, lying between the
mucous membrane and the Orbicularis oris, and anastomoses with the artery of
the opposite side. It supplies the upper lip, and gives off in its course two
or three vessels which ascend to the nose; a septal branch ramifies on
the nasal septum as far as the point of the nose, and an alar branch
supplies the ala of the nose.
The Lateral Nasal branch is derived from the external
maxillary as that vessel ascends along the side of the nose. It supplies the
ala and dorsum of the nose, anastomosing with its fellow, with the septal and
alar branches, with the dorsal nasal branch of the ophthalmic, and with the
infraorbital branch of the internal maxillary.
The Angular Artery (a. angularis) is the
terminal part of the external maxillary; it ascends to the medial angle of the
orbit, imbedded in the fibers of the angular head of the Quadratus labii
superioris, and accompanied by the angular vein. On the cheek it distributes
branches which anastomose with the infraorbital; after supplying the lacrimal
sac and Orbicularis oculi, it ends by anastomosing with the dorsal nasal branch
of the ophthalmic artery.
The Muscular Branches in the neck are distributed to
the Pterygoideus internus and Stylohyoideus, and on the face to the Masseter
and Buccinator. The anastomoses of the external maxillary artery are very
numerous, not only with the vessel of the opposite side, but, in the neck,
with the sublingual branch of the lingual, with the ascending pharyngeal, and
by its ascending palatine and tonsillar branches with the palatine branch of
the internal maxillary; on the face, with the mental branch of the
inferior alveolar as it emerges from the mental foramen, with the transverse
facial branch of the superficial temporal, with the infraorbital branch of the
internal maxillary, and with the dorsal nasal branch of the ophthalmic.
Peculiarities.—The external maxillary
artery not infrequently arises in common with the lingual. It varies in its
size and in the extent to which it supplies the face; it occasionally ends as
the submental, and not infrequently extends only as high as the angle of the
mouth or nose. The deficiency is then compensated for by enlargement of one of
the neighboring arteries.
4. The occipital artery (a. occipitalis) (508) arises from the posterior part of the
external carotid, opposite the external maxillary, near the lower margin of the
posterior belly of the Digastricus, and ends in the posterior part of the
scalp.
Course and Relations.—At its origin, it is
covered by the posterior belly of the Digastricus and the Stylohyoideus, and
the hypoglossal nerve winds around it from behind forward; higher up, it
crosses the internal carotid artery, the internal jugular vein, and the vagus
and accessory nerves. It next ascends to the interval between the transverse
process of the atlas and the mastoid process of the temporal bone, and passes
horizontally backward, grooving the surface of the latter bone, being covered
by the Sternocleidomastoideus, Splenius capitis, Longissimus capitis, and
Digastricus, and resting upon the Rectus capitis lateralis, the Obliquus
superior, and Semispinalis capitis. It then changes its course and runs
vertically upward, pierces the fascia connecting the cranial attachment of the
Trapezius with the Sternocleidomastoideus, and ascends in a tortuous course in
the superficial fascia of the scalp, where it divides into numerous branches,
which reach as high as the vertex of the skull and anastomose with the
posterior auricular and superficial temporal arteries. Its terminal portion is
accompanied by the greater occipital nerve.
Branches.—The branches of the occipital artery are:
Muscular.
Sternocleidomastoid.
Auricular.
Meningeal.
Descending.
The Muscular Branches (rami musculares) supply
the Digastricus, Stylohyoideus, Splenius, and Longissimus capitis.
The Sternocleidomastoid Artery (a. sternocleidomastoidea;
sternomastoid artery) generally arises from the occipital close to
its commencement, but sometimes springs directly from the external carotid. It
passes downward and backward over the hypoglossal nerve, and enters the
substance of the muscle, in company with the accessory nerve.
The Auricular Branch (ramus auricularis)
supplies the back of the concha and frequently gives off a branch, which enters
the skull through the mastoid foramen and supplies the dura mater, the
diploë, and the mastoid cells; this latter branch sometimes arises from
the occipital artery, and is then known as the mastoid branch.
The Meningeal Branch (ramus meningeus; dural
branch) ascends with the internal jugular vein, and enters the skull
through the jugular foramen and condyloid canal, to supply the dura mater in
the posterior fossa.
The Descending Branch (ramus descendens; arteria
princeps cervicis) (513), the largest branch of
the occipital, descends on the back of the neck, and divides into a superficial
and deep portion. The superficial portion runs beneath the Splenius, giving off
branches which pierce that muscle to supply the Trapezius and anastomose with
the ascending branch of the transverse cervical: the deep portion runs down between
the Semispinales capitis and colli, and anastomoses with the vertebral and with
the a. profunda cervicalis, a branch of the costocervical trunk. The
anastomosis between these vessels assists in establishing the collateral
circulation after ligature of the common carotid or subclavian artery.
The terminal branches of the occipital artery are
distributed to the back of the head: they are very tortuous, and lie between
the integument and Occipitalis, anastomosing with the artery of the opposite
side and with the posterior auricular and temporal arteries, and supplying the
Occipitalis, the integument, and pericranium. One of the terminal branches may
give off a meningeal twig which passes through the parietal foramen.
5. The posterior auricular artery (a. auricularis
posterior) (508) is small and arises
from the external carotid, above the Digastricus and Stylohyoideus, opposite
the apex of the styloid process. It ascends, under cover of the parotid gland,
on the styloid process of the temporal bone, to the groove between the
cartilage of the ear and the mastoid process, immediately above which it
divides into its auricular and occipital branches.
Branches.—Besides several small branches to
the Digastricus, Stylohyoideus, and Sternocleidomastoideus, and to the parotid
gland, this vessel gives off three branches:
Stylomastoid.
Auricular.
Occipital.
The Stylomastoid Artery (a. stylomastoidea)
enters the stylomastoid foramen and supplies the tympanic cavity, the tympanic antrum
and mastoid cells, and the semicircular canals. In the young subject a branch
from this vessel forms, with the anterior tympanic artery from the internal
maxillary, a vascular circle, which surrounds the tympanic membrane, and from
which delicate vessels ramify on that membrane. It anastomoses with the
superficial petrosal branch of the middle meningeal artery by a twig which
enters the hiatus canalis facialis.
The Auricular Branch (ramus auricularis)
ascends behind the ear, beneath the Auricularis posterior, and is distributed
to the back of the auricula, upon which it ramifies minutely, some branches
curving around the margin of the cartilage, others perforating it, to supply
the anterior surface. It anastomoses with the parietal and anterior auricular
branches of the superficial temporal.
The Occipital Branch (ramus occipitalis)
passes backward, over the Sternocleidomastoideus, to the scalp above and behind
the ear. It supplies the Occipitalis and the scalp in this situation and
anastomoses with the occipital artery.
6. The ascending pharyngeal artery (a. pharyngea
ascendens) (513), the smallest branch of
the external carotid, is a long, slender vessel, deeply seated in the neck,
beneath the other branches of the external carotid and under the
Stylopharyngeus. It arises from the back part of the external carotid,
near the commencement of that vessel, and ascends vertically between the
internal carotid and the side of the pharynx, to the under surface of the base
of the skull, lying on the Longus capitis.
Branches.—Its branches are:
Pharyngeal.
Prevertebral.
Palatine.
Inferior Tympanic.
Posterior Meningeal.
The Pharyngeal Branches (rami pharyngei) are
three or four in number. Two of these descend to supply the Constrictores
pharyngis medius and inferior and the Stylopharyngeus, ramifying in their
substance and in the mucous membrane lining them.
The Palatine Branch varies in size, and may take the
place of the ascending palatine branch of the facial artery, when that vessel
is small. It passes inward upon the Constrictor pharyngis superior, sends
ramifications to the soft palate and tonsil, and supplies a branch to the
auditory tube.
The Prevertebral Branches are numerous small vessels,
which supply the Longi capitis and colli, the sympathetic trunk, the
hypoglossal and vagus nerves, and the lymph glands; they anastomose with the
ascending cervical artery.
The Inferior Tympanic Artery (a. tympanica
inferior) is a small branch which passes through a minute foramen in the
petrous portion of the temporal bone, in company with the tympanic branch of
the glossopharyngeal nerve, to supply the medial wall of the tympanic cavity
and anastomose with the other tympanic arteries.
The Meningeal Branches are several small vessels,
which supply the dura mater. One, the posterior meningeal, enters the
cranium through the jugular foramen; a second passes through the foramen
lacerum; and occasionally a third through the canal for the hypoglossal nerve.
7. The superficial temporal artery (a. temporalis
superficialis) (508), the smaller of the two
terminal branches of the external carotid, appears, from its direction, to be
the continuation of that vessel. It begins in the substance of the parotid gland,
behind the neck of the mandible, and corsses over the posterior root of the
zygomatic process of the temporal bone; about
Relations.—As it crosses the
zygomatic process, it is covered by the Auricularis anterior muscle, and by a
dense fascia; it is crossed by the temporal and zygomatic branches of the
facial nerve and one or two veins, and is accompanied by the auriculotemporal
nerve, which lies immediately behind it.
Branches.—Besides some twigs to the parotid
gland, to the temporomandibular joint, and to the Masseter muscle, its branches
are:
Transverse Facial.
Anterior Auricular.
Middle Temporal.
Frontal.
Parietal.
The Transverse Facial Artery (a. transversa faciei)
is givien off from the superficial temporal before that vessel quits the
parotid gland; running forward through the substance of the gland, it passes
transversely across the side of the face, between the parotid duct and the
lower border of the zygomatic arch, and divides into numerous branches, which
supply the parotid gland and duct, the Masseter, and the integument, and
anastomose with the external maxillary, masseteric, buccinator, and
infraorbital arteries. This vessel rests on the Masseter, and is accompanied by
one or two branches of the facial nerve.
The Middle Temporal Artery (a. temporalis media)
arises immediately above the zygomatic arch, and, perforating the
temporal fascia, gives branches to the Temporalis, anastomosing with the deep
temporal branches of the internal maxillary. It occasionally gives off a zygomaticoörbital
branch, which runs along the upper border of the zygomatic arch, between
the two layers of the temporal fascia, to the lateral angle of the orbit. This
branch, which may arise directly from the superficial temporal artery, supplies
the Orbicularis oculi, and anastomoses with the lacrimal and palpebral branches
of the ophthalmic artery.
The Anterior Auricular Branches (rami auriculares
anteriores) are distributed to the anterior portion of the auricula, the
lobule, and part of the external meatus, anastomosing with the posterior
auricular.
The Frontal Branch (ramus frontalis; anterior
temporal) runs tortuously upward and forward to the forehead, supplying the
muscles, integument, and pericranium in this region, and anastomosing with the
supraorbital and frontal arteries.
The Parietal Branch (ramus parietalis; posterior
temporal) larger than the frontal, curves upward and backward on the side
of the head, lying superficial to the temporal fascia, and anastomosing with
its fellow of the opposite side, and with the posterior auricular and occipital
arteries.
8. The maxillary artery (a. maxillaris) (510), the larger of the two
terminal branches of the external carotid, arises behind the neck of the
mandible, and is at first imbedded in the substance of the parotid gland; it
passes forward between the ramus of the mandible and the sphenomandibular
ligament, and then runs, either superficial or deep to the Pterygoideus
externus, to the pterygopalatine fossa. It supplies the deep structures of the
face, and may be divided into mandibular, pterygoid, and pterygopalatine
portions.
The first or mandibular portion passes
horizontally forward, between the ramus of the mandible and the
sphenomandibular ligament, where it lies parallel to and a little below the
auriculotemporal nerve; it crosses the inferior alveolar nerve, and runs along
the lower border of the Pterygoideus externus.
The second or pterygoid portion runs obliquely
forward and upward under cover of the ramus of the mandible and insertion of
the Temporalis, on the superficial (very frequently on the deep) surface of the
Pterygoideus externus; it then passes between the two heads of origin of this
muscle and enters the fossa.
The third or pterygopalatine portion lies in
the pterygopalatine fossa in relation with the sphenopalatine ganglion.
The branches of this vessel may be divided into three groups
(511), corresponding with its
three divisions.
Branches of the First or Mandibular Portions.
Anterior Tympanic.
Middle Meningeal.
Deep Auricular.
Accessory Meningeal
Inferior Alveolar.
The Anterior Tympanic Artery (a. tympanica
anterior; tympanic artery) passes upward behind the temporomandibular
articulation, enters the tympanic cavity through the petrotympanic fissure, and
ramifies upon the tympanic membrane, forming a vascular circle around the
membrane with the stylomastoid branch of the posterior auricular, and
anastomosing with the artery of the pterygoid canal and with the
caroticotympanic branch from the internal carotid.
Plan of branches of maxillary artery.
The Deep Auricular Artery (a. auricularis profunda)
often arises in common with the preceding. It ascends in the substance
of the parotid gland, behind the temporomandibular articulation, pierces the
cartilaginous or bony wall of the external acoustic meatus, and supplies its
cuticular lining and the outer surface of the tympanic membrane. It gives a
branch to the temporomandibular joint.
The Middle Meningeal Artery (a. meningea media;
medidural artery) is the largest of the arteries which supply the dura mater. It ascends
between the sphenomandibular ligament and the Pterygoideus externus, and
between the two roots of the auriculotemporal nerve to the foramen spinosum of
the sphenoid bone, through which it enters the cranium; it then runs forward in
a groove on the great wing of the sphenoid bone, and divides into two branches,
anterior and posterior. The anterior branch, the larger, crosses the
great wing of the sphenoid, reaches the groove, or canal, in the sphenoidal
angle of the parietal bone, and then divides into branches which spread out
between the dura mater and internal surface of the cranium, some passing upward
as far as the vertex, and others backward to the occipital region. The posterior
branch curves backward on the squama of the temporal bone, and, reaching
the parietal some distance in front of its mastoid angle, divides into branches
which supply the posterior part of the dura mater and cranium. The branches of
the middle meningeal artery are distributed partly to the dura mater, but
chiefly to the bones; they anastomose with the arteries of the opposite side,
and with the anterior and posterior meningeal.
The middle meningeal on entering the cranium gives off the
following branches: (1) Numerous small vessels supply the semilunar ganglion
and the dura mater in this situation. (2) A superficial petrosal branch
enters the hiatus of the facial canal, supplies the facial nerve, and
anastomoses with the stylomastoid branch of the posterior auricular artery. (3)
A superior tympanic artery runs in the canal for the Tensor tympani, and
supplies this muscle and the lining membrane of the canal. (4) Orbital
branches pass through the superior orbital fissure or through separate
canals in the great wing of the sphenoid, to anastomose with the lacrimal or
other branches of the ophthalmic artery. (5) Temporal branches pass
through foramina in the great wing of the sphenoid, and anastomose in the
temporal fossa with the deep temporal arteries.
The Accessory Meningeal Branch (ramus meningeus
accessorius; small meningeal or parvidural branch) is sometimes derived
from the preceding. It enters the skull through the foramen ovale, and supplies
the semilunar ganglion and dura mater.
The Inferior Alveolar Artery (a. alveolaris
inferior; inferior dental artery) descends with the inferior alveolar nerve
to the mandibular foramen on the medial surface of the ramus of the mandible.
It runs along the mandibular canal in the substance of the bone, accompanied by
the nerve, and opposite the first premolar tooth divides into two branches,
incisor and mental. The incisor branch is continued forward beneath the
incisor teeth as far as the middle line, where it anastomoses with the artery
of the opposite side; the mental branch escapes with the nerve at the
mental foramen, supplies the chin, and anastomoses with the submental and
inferior labial arteries. Near its origin the inferior alveolar artery gives
off a lingual branch which descends with the lingual nerve and supplies
the mucous membrane of the mouth. As the inferior alveolar artery enters the
foramen, it gives off a mylohyoid branch which runs in the mylohyoid
groove, and ramifies on the under surface of the Mylohyoideus. The inferior alveolar
artery and its incisor branch during their course through the substance of the
bone give off a few twigs which are lost in the cancellous tissue, and a series
of branches which correspond in number to the roots of the teeth: these enter
the minute apertures at the extremities of the roots, and supply the pulp of
the teeth.
Branches of the Second or Pterygoid Portion.—
Deep Temporal.
Masseteric.
Pterygoid.
Buccinator.
The Deep Temporal Branches, two in number, anterior
and posterior, ascend between the Temporalis and the pericranium; they
supply the muscle, and anastomose with the middle temporal artery; the anterior
communicates with the lacrimal artery by means of small branches which
perforate the zygomatic bone and great wing of the sphenoid.
The Pterygoid Branches (rami pterygoidei),
irregular in their number and origin, supply the Pterygoidei.
The Masseteric Artery (a. masseterica) is
small and passes lateralward through the mandibular notch to the deep surface
of the Masseter. It supplies the muscle, and anastomoses with the masseteric
branches of the external maxillary and with the transverse facial artery.
The Buccinator Artery (a. buccinatoria; buccal
artery) is small and runs obliquely forward, between the Pterygoideus
internus and the insertion of the Temporalis, to the outer surface of the
Buccinator, to which it is distributed, anastomosing with branches of the
external maxillary and with the infraorbital.
Branches of the Third or Pterygopalatine Portion.—
Posterior Superior Alveolar.
Artery of the Pterygoid Canal.
Infraorbital.
Pharyngeal.
Descending Palatine.
Sphenopalatine.
The Posterior Superior Alveolar Artery (a.
alveolaris superior posterior; alveolar or posterior dental artery) is
given off from the internal maxillary, frequently in conjunction with the
infraorbital just as the trunk of the vessel is passing into the
pterygopalatine fossa. Descending upon the tuberosity of the maxilla, it
divides into numerous branches, some of which enter the alveolar canals, to
supply the molar and premolar teeth and the lining of the maxillary sinus,
while others are continued forward on the alveolar process to supply the gums.
The Infraorbital Artery (a. infraorbitalis)
appears, from its direction, to be the continuation of the trunk of the
internal maxillary, but often arises in conjunction with the posterior
superior alveolar. It runs along the infraorbital groove and canal with the
infraorbital nerve, and emerges on the face through the infraorbital foramen,
beneath the infraorbital head of the Quadratus labii superioris. While in the
canal, it gives off (a) orbital branches which assist in
supplying the Rectus inferior and Obliquus inferior and the lacrimal sac, and (b)
anterior superior alveolar branches which descend through the anterior
alveolar canals to supply the upper incisor and canine teeth and the mucous
membrane of the maxillary sinus. On the face, some branches pass upward to the
medial angle of the orbit and the lacrimal sac, anastomosing with the angular
branch of the external maxillary artery; others run toward the nose,
anastomosing with the dorsal nasal branch of the ophthalmic; and others descend
between the Quadratus labii superioris and the Caninus, and anastomose with the
external maxillary, transverse facial, and buccinator arteries. The four
remaining branches arise from that portion of the internal maxillary
which is contained in the pterygopalatine fossa.
The Descending Palatine Artery (a. palatina
descendens) descends through the pterygopalatine canal with the anterior
palatine branch of the sphenopalatine ganglion, and, emerging from the greater
palatine foramen, runs forward in a groove on the medial side of the alveolar
border of the hard palate to the incisive canal; the terminal branch of the
artery passes upward through this canal to anastomose with the sphenopalatine
artery. Branches are distributed to the gums, the palatine glands, and the
mucous membrane of the roof of the mouth; while in the pterygopalatine canal it
gives off twigs which descend in the lesser palatine canals to supply the soft
palate and palatine tonsil, anastomosing with the ascending palatine artery.
The Artery of the Pterygoid Canal (a. canalis
pterygoidei; Vidian artery) passes backward along the pterygoid canal with
the corresponding nerve. It is distributed to the upper part of the pharynx and
to the auditory tube, sending into the tympanic cavity a small branch which
anastomoses with the other tympanic arteries.
The Pharyngeal Branch is very small; it runs backward
through the pharyngeal canal with the pharyngeal nerve, and is distributed to
the upper part of the pharynx and to the auditory tube.
The Sphenopalatine Artery (a. sphenopalatina;
nasopalatine artery) passes through the sphenopalatine foramen into the
cavity of the nose, at the back part of the superior meatus. Here it gives off
its posterior lateral nasal branches which spread forward over the
conchæ and meatuses, anastomose with the ethmoidal arteries and the nasal
branches of the descending palatine, and assist in supplying the frontal,
maxillary, ethmoidal, and sphenoidal sinuses. Crossing the under surface of the
sphenoid the sphenopalatine artery ends on the nasal septum as the posterior
septal branches; these anastomose with the ethmoidal arteries and the
septal branch of the superior labial; one branch descends in a groove on the
vomer to the incisive canal and anastomoses with the descending palatine
artery.
Internal carotid
artery. Blood vessels of orbit
Internal
carotid artery disposes at first laterally and behind then
medially from external carotid artery, passes vertically upward [cervical
portion] and get into external foramen of carotid canal (temporal
pyramid). Passing in carotid canal [petrosal portion], it gives off the caroticotympanic
arteries for tympanic cavity. After passing out from the internal
foramen of canal internal carotid artery lies into carotid sulcus of
sphenoid bone, passes through the cavernous sinus [cavernous portion
of artery], on level of optic canal gives off an ophthalmic artery and
divides into branches: anterior cerebral artery and middle cerebral
artery, posterior communicating artery.
Superficial
dissection of the right side of the neck, showing the carotid and subclavian
arteries.
Artery of the
Pterygoid Canal.
4.
The hypophyseal branches are one or two minute vessels supplying the
hypophysis.
5.
The semilunar branches are small vessels to the semilunar ganglion.
7.
The ophthalmic artery (a. ophthalmica) 
The ophthalmic
artery and its branches.
8.
The anterior cerebral artery (a. cerebri anterior) (517, 
Branches.—The branches of this vessel are the:
Medial surface of cerebral
hemisphere, showing areas supplied by cerebral arteries.
10. The
posterior communicating artery (a. communicans posterior) 516, 
The three trunks which together supply each cerebral
hemisphere arise from the arterial circle of Willis. From its anterior part
proceed the two anterior cerebrals, from its antero-lateral parts the middle
cerebrals, and from its posterior part the posterior cerebrals. Each of these
principal arteries gives origin to two different systems of secondary vessels.
One of these is named the ganglionic system, and the vessels belonging
to it supply the thalami and corpora striata; the other is the cortical
system, and its vessels ramify in the pia mater and supply the cortex and
subjacent brain substance. These two systems do not communicate at any point of
their peripheral distribution, but are entirely independent of each other, and
there is between the parts supplied by the two systems a borderland of
diminished nutritive activity, where, it is said, softening is especially
liable to occur in the brains of old people.
The Ganglionic System.—All the vessels of
this system are given off from the arterial circle of Willis, or from the
vessels close to it. They form six principal groups: (I) the antero-medial
group, derived from the anterior cerebrals and anterior communicating; (II)
the postero-medial group, from the posterior cerebrals and posterior
communicating; (III and IV) the right and left antero-lateral groups,
from the middle cerebrals; and (V and VI) the right and left postero-lateral
groups, from the posterior cerebrals, after they have wound around the
cerebral peduncles. The vessels of this system are larger than those of the
cortical system, and are what Cohnheim designated terminal arteries—that
is to say, vessels which from their origin to their termination neither supply
nor receive any anastomotic branch, so that, through any one of the vessels
only a limited area of the thalamus or corpus striatum can be injected, and the
injection cannot be driven beyond the area of the part supplied by the
particular vessel which is the subject of the experiment.
The Cortical Arterial System.—The
vessels forming this system are the terminal branches of the anterior, middle,
and posterior cerebral arteries. They divide and ramify in the substance of the
pia mater, and give off branches which penetrate the brain cortex,
perpendicularly. These branches are divisible into two classes, long and short.
The long, or medullary arteries, pass through the gray substance
and penetrate the subjacent white substance to the depth of 3 or
Internal thoracic artery begins from inferior surface of subclavian artery and passes along І-VII cartilages of ribs near sternum, where disintegrates on two terminal branches are musculо-phrenic artery and superior epigastric artery. Internal thoracic artery gives off rami for thymus, bronchі, pericardium and sternum. Also from this artery moves away rami mammarii, tracheal rami, anterior intercostal branches, which supply intercostal muscles. Superior epigastric artery gets into sheath of rectus abdominal muscle, supplies this muscle and anastomoses with inferior epigastric artery on navel level.
Thyro-cervical trunk is has
length 1-
In interscalenus space subclavian
artery gives off costo-cervical trunk, which ramifies into deep
cervical artery, which supplies semispinalis capitis and cervicis muscles
and suprema intercostal artery, which ramifies into I and ІІ intercostal
spaces, supplying intercostal muscles.
After
interscalenus space space subclavian artery gives off
transverse
colli artery, which continues into dorsal scapulae artery.
They supply rhomboid, levator scapulae and shoulder girdle muscles.
The artery which supplies the upper extremity continues as a single
trunk from its commencement down to the elbow; but different portions of it
have received different names, according to the regions through which they
pass. That part of the vessel which extends from its origin to the outer border
of the first rib is termed the subclavian;
beyond this point to the lower border of the axilla it is named the axillary; and from the lower margin of
the axillary space to the bend of the elbow it is termed brachial; here the trunk ends by
dividing into two branches the radial
and ulnar.
The
internal mammary artery and its branches.
The Subclavian Artery (a. Subclavia).
—On the right
side the subclavian artery arises
from the innominate artery behind the right sternoclavicular articulation; on
the left side it springs from the arch of the aorta. The two vessels,
therefore, in the first part of their course, differ in length, direction, and
relation with neighboring structures.
The
left subclavian is occasionally joined at its origin with the left carotid.
The
chief agent in the restoration of the axillary artery below the tumor was the
subscapular artery, which communicated most freely with the internal mammary,
transverse scapular and descending ramus of the transverse cervical branches of
the subclavian, from all of which it received so great an influx of blood as to
dilate it to three times its natural size. 101
Branches.—The branches of the subclavian artery are:
Posterior
Inferior Cerebellar.
Its branches, on either side, are the
following:
The branches of the posterior cerebral
artery are divided into two sets, ganglionic
and cortical:
The branches of the inferior thyroid are:
The scapular and
circumflex arteries.
The Descending Aorta
The descending aorta is continuous with the aortic arch. The diaphragm divides
the descending aorta into a superior thoracic aorta and an inferior abdominal
aorta (Figures 21-26;){kind=small}
, 21-27;){kind=small}
, and 21-28;){kind=small}
.
The Thoracic Aorta. The thoracic aorta begins at the level of vertebra T5
and penetrates the diaphragm at the level of vertebra T12. The
thoracic aorta travels within the mediastinum, on the dorsal thoracic wall,
slightly to the left of the vertebral column. It supplies blood to branches
servicing the tissues and organs of the mediastinum, the muscles of the chest
and the diaphragm, and the thoracic spinal cord.
The branches of the thoracic aorta are anatomically
grouped as either visceral branches or parietal branches.
Visceral branches supply the organs of the chest: The bronchial arteries supply
the nonrespiratory tissues of the lungs, the pericardial arteries supply the
pericardium, the esophageal arteries supply the esophagus, and the mediastinal
arteries supply the tissues of the mediastinum. The parietal branches supply
the chest wall: The intercostal arteries supply the chest muscles and the
vertebral column area, and the superior phrenic arteries deliver blood to the
superior surface of the diaphragm, which separates the thoracic and
abdominopelvic cavities. The branches of the thoracic aorta are detailed in
Figure 21-26.
The Abdominal Aorta. The abdominal aorta, which begins immediately inferior
to the diaphragm, is a continuation of the thoracic aorta (Figure 21-26). The abdominal aorta descends slightly to the left
of the vertebral column but posterior to the peritoneal cavity. It is commonly
surrounded by a cushion of adipose tissue. At the level of vertebra L4,
the abdominal aorta splits into two major arteries—the left and right
common iliac arteries—that supply deep pelvic structures and the lower
limbs. The region where the aorta splits is called the terminal segment of
the aorta.
The abdominal aorta delivers blood to all the
abdominopelvic organs and structures. The major branches to visceral organs are
unpaired, and they arise on the anterior surface of the abdominal aorta and
extend into the mesenteries. Branches to the body wall, the kidneys, the
urinary bladder, and other structures outside the abdominopelvic cavity are
paired, and they originate along the lateral surfaces of the abdominal aorta.
Figure 21-26 shows the major arteries of the trunk after removal
of most of the thoracic and abdominal organs. Figure 21-27 ;){kind=small}
gives the distribution of those arteries to
abdominopelvic organs.
The abdominal aorta gives rise to three unpaired
arteries (Figures 21-26 and 21-27 ;){kind=small}
;){kind=small}
):
- The celiac artery
delivers blood to the liver, stomach, and spleen. The celiac divides into three branches:
- The left gastric artery,
which supplies the stomach and inferior portion of the esophagus.
- The splenic artery, which
supplies the spleen and arteries to the stomach (left gastroepiploic)
and pancreas (pancreatic).
- The common hepatic
artery, which supplies arteries to the liver (hepatic),
stomach (right gastric), gallbladder (cystic),
and duodenal area (gastroduodenal, right gastroepiploic, and superior
pancreaticoduodenal artery).
- The superior mesenteric artery arises about
- The inferior mesenteric
artery arises about
The abdominal aorta also gives rise to five paired
arteries:
- The inferior phrenics,
which supply the inferior surface of the diaphragm.
- The suprarenal arteries,
which originate on either side of the aorta near the base of the superior
mesenteric artery. Each suprarenal artery supplies one of the adrenal
glands that cap the superior portion of the kidneys.
- The short (about
- The gonadal arteries,
which originate between the superior and inferior mesenteric arteries. In
males, they are called testicular arteries and are long, thin
arteries that supply blood to the testes and scrotum. In females, they are
termed ovarian arteries and supply blood to the ovaries, uterine
tubes, and uterus. The distribution of gonadal vessels (both arteries and
veins) differs in males and females; we shall describe the differences in
Chapter 28.
- Small lumbar arteries,
which arise on the posterior surface of the aorta and supply the
vertebrae, spinal cord, and abdominal wall.
Arteries of the Pelvis and
Lower Limbs
Near the level of vertebra L4, the terminal segment of the abdominal
aorta divides to form a pair of elastic arteries, the right and left common
iliac arteries. These arteries carry blood to the pelvis and lower limbs
(Figures 21-28 and 21-29;){kind=small}
). As these arteries travel along the inner surface of
the ilium, they descend posterior to the cecum and sigmoid colon. At the level
of the lumbosacral joint, each common iliac divides to form an internal iliac
artery and an external iliac artery (Figure 21-27). The internal iliac arteries enter the pelvic cavity
to supply the urinary bladder, the internal and external walls of the pelvis, the
external genitalia, the medial side of the thigh, and, in females, the uterus
and vagina. The external iliac arteries supply blood to the lower limbs, and
they are much larger in diameter than the internal iliac arteries.
Arteries of the Thigh and Leg. The external iliac artery crosses the surface of the
iliopsoas muscle and penetrates the abdominal wall midway between the anterior
superior iliac spine and the pubic symphysis. It emerges on the anteromedial
surface of the thigh as the femoral artery. Roughly ). The deep femoral artery, which gives rise to the medial
and lateral circumflex arteries, supplies blood to the ventral and
lateral regions of the skin and deep muscles of the thigh.
The femoral artery continues inferiorly and posterior
to the femur. At the popliteal fossa, the femoral artery becomes the
popliteal artery. The popliteal artery crosses the popliteal fossa before
branching to form the posterior and anterior tibial arteries. The posterior
tibial artery gives rise to the peroneal artery and continues inferiorly along
the posterior surface of the tibia. The anterior tibial artery passes between
the tibia and fibula, emerging on the anterior surface of the tibia. As it
descends toward the foot, the anterior tibial provides blood to the skin and
muscles of the anterior portion of the leg.
Arteries of the Foot. When it reaches the ankle, the anterior tibial artery
becomes the dorsalis pedis artery. The dorsalis pedis branches repeatedly,
supplying the ankle and dorsal portion of the foot (Figure 21-28 ;){kind=small}
).
As it reaches the ankle, the posterior tibial artery
divides to form the medial and lateral plantar arteries, which supply blood to
the plantar surface of the foot. The medial and lateral plantar arteries are
connected to the dorsalis pedis artery through a pair of anastomoses. This
arrangement produces a dorsal arch (arcuate arch) and a plantar arch. Small arteries branching off these arches
supply the distal portions of the foot and the toes.
CONCEPT CHECK
QUESTIONS
- Blockage of which branch
from the aortic arch would interfere with the blood flow to the left arm?
- Why would compression of
the common carotid arteries cause a person to lose consciousness?
- Grace is in an automobile
accident and ruptures her celiac trunk. Which organs will be affected most
directly by this injury?