597
CHAPTER FIFTEEN
Cardiovascular System
side of the arm, whereas others descend on each side to the
elbow and connect with arteries in the forearm. The result-
ing arterial network allows blood to reach the forearm even
if a portion of the distal brachial artery becomes obstructed.
In the elbow, the brachial artery divides into an ulnar
artery and a radial artery. The
ulnar artery
leads downward on
the ulnar side of the forearm to the wrist. Some of its branches
join the anastomosis around the elbow joint, whereas others
supply blood to fl exor and extensor muscles in the forearm.
The
radial artery,
a continuation of the brachial artery,
extends along the radial side of the forearm to the wrist.
As it nears the wrist, it comes close to the surface and pro-
vides a convenient vessel for taking the pulse (radial pulse).
Branches of the radial artery join the anastomosis of the
elbow and supply the lateral muscles of the forearm.
At the wrist, the branches of the ulnar and radial arteries
join to form a network of vessels. Arteries arising from this
network supply blood to structures in the hand.
Arteries to the Thoracic and Abdominal
Walls
Blood reaches the thoracic wall through several vessels.
These include branches from the subclavian artery and the
thoracic aorta
(f
g. 15.48)
.
3.
Facial artery
to the pharynx, palate, chin, lips, and nose.
4.
Occipital artery
to the scalp on the back of the skull, the
meninges, the mastoid process, and various muscles in
the neck.
5.
Posterior auricular artery
to the ear and the scalp over
the ear.
The external carotid artery terminates by dividing into
maxillary
and
superf
cial temporal arteries.
The maxillary
artery supplies blood to the teeth, gums, jaws, cheek, nasal
cavity, eyelids, and meninges. The temporal artery extends
to the parotid salivary gland and to various surface regions
of the face and scalp.
The
internal carotid artery
follows a deep course
upward along the pharynx to the base of the skull. Entering
the cranial cavity, it provides the major blood supply to
the brain. The major branches of the internal carotid artery
include the following:
1.
Ophthalmic artery
to the eyeball and to various muscles
and accessory organs within the orbit.
2.
Posterior communicating artery
that forms part of the
cerebral arterial circle.
3.
Anterior choroid artery
to the choroid plexus within the
lateral ventricle of the brain and to nerve structures in
the brain.
The internal carotid artery terminates by dividing into
anterior
and
middle cerebral arteries.
The middle cerebral
artery passes through the lateral tissue and supplies the lateral
surface of the cerebrum, including the primary motor and sen-
sory areas of the face and upper limbs, the optic radiations,
and the speech area (see chapter 11, pp. 401–402). The ante-
rior cerebral artery extends anteriorly between the cerebral
hemispheres and supplies the medial surface of the brain.
Near the base of each internal carotid artery is an
enlargement called a
carotid sinus.
Like the aortic sinuses,
these structures contain baroreceptors that control blood
pressure. A number of small epithelial masses, called
carotid
bodies,
are also in the wall of the carotid sinus. These bodies
are vascular and have chemoreceptors that act with those of
the aortic bodies to regulate circulation and respiration.
Arteries to the Shoulder and Upper Limb
The subclavian artery, after giving off branches to the neck,
continues into the arm
(f
g. 15.47)
. It passes between the
clavicle and the F
rst rib and becomes the axillary artery.
The
axillary artery
supplies branches to structures
in the axilla and the chest wall, including the skin of the
shoulder; part of the mammary gland; the upper end of the
humerus; the shoulder joint; and muscles in the back, shoul-
der, and chest. As this vessel leaves the axilla, it becomes
the brachial artery.
The
brachial artery
courses along the humerus to the
elbow. It gives rise to a
deep brachial artery
that curves pos-
teriorly around the humerus and supplies the triceps mus-
cle. Shorter branches pass into the muscles on the anterior
Right common carotid a.
Right subclavian a.
Anterior circumflex a.
Posterior circumflex a.
Axillary a.
Brachial a.
Radial recurrent a.
Radial a.
Principal
artery of
thumb
Ulnar a.
Deep volar arch a.
Superficial volar arch a.
Digital a.
Ulnar recurrent a.
Deep brachial a.
FIGURE 15.47
The major arteries to the shoulder and upper limb.
(
a.
stands for artery.)
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