Download Internal Carotid Artery Beginning

VESSELS AND
NERVES
OF THE NECK
Main Arteries of the neck
1. Common Carotid Artery.
2. External Carotid Artery.
3. Internal Carotid Artery.
4. Subclavian Artery.
Main Veins of the neck
1. Internal Jugular vein.
2. Subclavian vein.
Main Nerves of the neck
Vagus nerve.
Accessory nerve.
Hypoglossal nerve.
Cervical part of sympathetic
trunk.
5. Cervical plexus.
6. Phrenic nerve.
1.
2.
3.
4.
Common Carotid Artery
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Beginning: the right from the brachiocephalic trunk
behind the sternoclavicular joint. The left arises
directly from the arch of aorta in the superior
mediastinum of thorax.
End: at the level of the upper border of thyroid
cartilage (3rd cervical vertebra) by dividing into
internal and external carotid arteries.
At its end (or beginning of internal carotid) there is a
dilatation called carotid sinus which is sensitive to
blood pressure changes. It has pressoreceptors
which are innervated by glossopharyngeal nerve.
Course and Relations
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It ascends in the neck, enclosed in the carotid
sheath with internal jugular vein and vagus nerve.
Anterolateral relations: Skin, superficial fascia,
investing fascia, sternocleidomastoid, sternohyoid,
sternothyroid and superior belly of omohyoid.
Posterior relation: Transverse processes of lower 4
cervical vertebra, prevertebral muscles and
sympathetic trunk.
Medial relations: larynx, pharynx, thyroid gland,
trachea and esophagus.
Lateral relation: Internal jugular vein and
(posterolaterally) vagus nerve
External Carotid Artery
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Beginning: One of the two terminal branches of the
common carotid artery. It begins at the level of the
upper border of thyroid cartilage (3rd cervical
vertebra).
End: behind the neck of the mandible, within the
substance of parotid gland by dividing into maxillary
and superficial temporal arteries.
At is beginning, the artery lies medial to the internal
carotid artery but as it ascends in the neck passes
backward and laterally.
It is crossed by the posterior belly of digastric and
stylohyoid muscles.
Relations
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Anterolateral relations: At its beginning, it is
overlapped by sternocleidomastoid. Above, it is
covered by skin, superficial fascia, investing deep
fascia. It is crossed by hypoglossal nerve, posterior
belly of digastric and stylohyoid. Within parotid
gland, it is crossed by facial nerve. Internal jugular
vein first lies lateral then posterior to the artery.
Medial relations: pharynx, internal carotid artery.
Structures passing between external and internal
carotid arteries: Styloid process, stylopharyngeus
muscle, glossopharyngeal nerve, pharyngeal branch
of vagus and parotid gland.
Branches:
1.
2.
3.
Superior thyroid artery: It arises from the
anterior aspect and gives muscular branch to
the sternocleidomastoid and superior laryngeal
artery, it supplies the thyroid gland.
Ascending pharyngeal artery: It emerges from
the medial side of the artery. It ascends on the
wall of the pharynx and supplies it.
Lingual artery: It arises from the anterior
aspect opposite the tip of greater horn of hyoid
bone. It makes a loop which is crossed by the
hypoglossal nerve, then it supplies the tongue.
Branches:
4.
5.
6.
Facial artery: It arises from the anterior aspect
just above the lingual artery (may arise in one
common trunk with lingual) & supplies the face.
Occipital artery: It emerges from the posterior
aspect of the artery. It ascends on the lower
border of the posterior belly of digastric and
accompanies greater occipital nerve to be
distributed on the back of the scalp.
Posterior auricular artery: It arises from the
posterior aspect and runs on the upper border of
posterior belly of digastric and reaches the
auricle.
Branches:
7.
Superficial temporal artery: One of the two
terminal branches of the ext. car. artery. It
arises within the substances of the parotid
gland and supplies the temporal region and
scalp.
8.
Maxillary artery: The other terminal branch
of the ext. car. artery. It arises within the
substances of the parotid gland and
supplies many regions (later).
Internal Carotid Artery
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Beginning: One of the two terminal branches of the
common carotid artery. It begins at the level of the
upper border of thyroid cartilage (3rd cervical
vertebra).
The artery enters the cranial cavity through the
carotid canal to be distributed to the brain, eye,
forehead and part of the nose.
It ascends in the neck enclosed in the carotid sheath
with the internal jugular vein and vagus nerve.
It is crossed by the posterior belly of digastric and
stylohyoid muscles.
It gives off NO BRANCHES in the neck.
Relations
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A.
B.
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Anterolateral relations:
Below the digastric muscle: At its beginning, it is overlapped
by sternocleidomastoid. Above, it is covered by skin,
superficial fascia, investing deep fascia. It is crossed by
hypoglossal nerve,
Above the digastric: stylohyoid, stylopharyngeus muscle,
glossopharyngeal nerve, pharyngeal branch of vagus,
parotid gland and external carotid artery.
Posterior relations: Sympathetic trunk, longus capitis and
transverse processes of the upper 3 cervical vertebrae.
Medial relations: pharynx and superior laryngeal nerve.
Structures passing between external and internal carotid
arteries: Styloid process, stylopharyngeus muscle,
glossopharyngeal nerve, pharyngeal branch of vagus and
parotid gland.
Subclavian artery
Beginning: the right from the
brachiocephalic trunk behind the
sternoclavicular joint. The left arises
directly from the arch of aorta in the
superior mediastinum of thorax.
 End: At the outer border of the first rib
where it continues as the axillary artery.
 The scalenus anterior muscle when passing
in front of the artery divides it into 3 parts;
1st, 2nd and 3rd.
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First part of Subclavian artery
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1.
2.
3.
Relations:
Anterior: common carotid artery, vagus
nerve and internal jugular vein.
Posterior: Dome of pleura, apex of the
lung and on right the right recurrent
laryngeal n.
Branches:
Vertebral artery.
Thyrocervical trunk.
Internal thoracic artery.
Second part of Subclavian artery
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Relations:
Anterior: scalenus anterior muscle.
Posterior: Dome of pleura, apex of the
lung.
Branches:
Costocervical trunk, which gives
1. Superior intercostal artery.
2. Deep cervical artery
Third Part of Subclavian Artery
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Course: enters the anteroinferior angle
of posterior triangle and disappears
behind the middle of the clavicle.
Together with the brachial plexus, it is
surrounded by extension from
prevertebral fascia called axillary
sheath.
Branches: No branches, but sometimes
the transverse cervical artery arises
from it.
Third Part of Subclavian Artery
Relations:
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Anteriorly: Skin, superficial fascia, external
jugular vein and investing deep cervical
fascia. At its beginning it is partially covered
by sternomastoid, and at its end it is
covered by clavicle.
Posteriorly: Lower trunk of brachial plexus
and scalenus medius.
Superiorly: Upper and middle trunks of
brachial plexus.
Inferiorly: Upper surface of the first rib.
Internal jugular vein
Beginning: at the jugular foramen as a
continuation of the sigmoid sinus.
 End: by uniting with the subclavian vein
behind the medial end of clavicle to form
the brachiocephalic vein.
 The vein has two dilatation; at its
beginning (superior bulb) and at its end
(inferior bulb).
 It descends in the neck within the carotid
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Tributaries of Internal jugular vein
1.
2.
3.
4.
5.
6.
7.
Inferior petrosal sinus.
Facial vein.
Pharyngeal veins.
Lingual vein.
Superior thyroid vein.
Middle thyroid vein.
Occipital vein (occasionally).