NERVES
OF
THE NECK
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.
Vagus Nerve
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It is a mixed nerve, it leaves the skull through the
jugular foramen.
It has two sensory ganglia (superior and inferior
ganglia).
At its beginning, it is joined by the cranial part of
accessory nerve (having motor fibers to pharynx
and palate).
It descends in the neck within the carotid sheath
in between carotid artery and internal jugular vein.
It descends in front of the 1st part of subclavian
artery, then enters the thorax.
Branches of Vagus Nerve
1.
Meningeal branch: for posterior cranial fossa.
2.
Auricular branch: sensory for the medial surface
of auricle, floor of external auditory meatus and
adjacent parts of outer surface of tympanic
membrane.
3.
Pharyngeal branch: (its fibers come from cranial
part of accessory nerve). It passes between ext.
and int. carotid arteries, and shares in pharyngeal
plexus around the wall of pharynx. It supplies all
muscles of palate (except tensor palati) and all
muscles of pharynx (except stylopharyngeus).
Branches of Vagus Nerve
4.
Superior laryngeal nerve: Descends toward the
larynx and divides into:
A. External laryngeal nerve that accompanies the
superior thyroid artery then deep to the thyroid
gland to supplies the cricothyroid muscle.
B. Internal laryngeal nerve that pierces the
thyrohyoid membrane and supplies the mucosa
of the piriform fossa of pharynx and mucosa of
larynx above the level of vocal fold.
5.
Cardiac branches: 2-3 nerves that share in
formation of cardiac plexus.
Branches of Vagus Nerve
6.
Right recurrent laryngeal nerve: arises from the
right vagus as it crosses the first part of the
subclavian artery. It hooks backward and upward
behind the artery, then ascends in the groove
between the trachea and esophagus. It passes
deep the thyroid gland with accompany of inferior
thyroid artery. It enters the larynx and supplies
all its intrinsic muscles (except cricothyroid) and
mucosa of the larynx below the level of the vocal
folds and upper part of trachea. (left recurrent
laryngeal nerve begins in the thorax).
Accessory Nerve
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It is a motor nerve and consists of cranial and
spinal (upper 5 cervical segments) parts.
It leaves the skull through the jugular foramen,
then the two parts separate again, the cranial part
joins the vagus nerve at its inferior ganglion and it
is distributed through it (mainly in the pharyngeal
plexus and recurrent laryngeal nerve).
The spinal part runs downward and laterally,
crosses the internal jugular vein, enters deep to
sternocleidomastoid, then crosses the posterior
triangle (on the levator scapulae muscle) and
enters deep to the trapezius muscle. It supplies
sternocleidomastoid and trapezius muscles.
Hypoglossal Nerve
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It is a motor nerve that supplies all muscles of the
tongue (except palatoglossus).
It leaves the skull through the hypoglossal canal,
then it has a short course in the carotid sheath
(with internal carotid artery, internal jugular vein,
glossopharyngeal, vagus and accessory nerves).
It passes between the internal carotid artery and
internal jugular vein (covered by the posterior
belly of digastric). It then curves up and anteriorly
crossing the first part of lingual artery and is
distributed to the lingual muscles.
At its beginning, it is joined by branch from the
cervical plexus (containing fibers from C1) which
supplies some muscles.
Branches of Hypoglossal Nerve
1.
2.
3.
4.
5.
Meningeal branch: for posterior cranial fossa.
Descending branch: Containing C1 fibers. It is
also called (descendens hypoglossi) and form the
superior root of ansa cervicalis.
Nerve to thyrohyoid: also contains C1 fibers and
supplies the thyrohyoid muscle.
Nerve to geniohyoid: also contains C1 fibers and
supplies the geniohyoid muscle.
Muscular branches of the tongue: supplies all
intrinsic and extrinsic muscles of the tongue
except palatoglossus (from pharyngeal plexus).
Cervical sympathetic trunk
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It extends upward till the base of the skull and
below to the neck of the first rib where it
continues in the thorax.
It lies behind the common and internal carotid
arteries (posterior to the carotid sheath).
It possesses three ganglia; superior, middle and
inferior.
Superior ganglion is the larger and longer and lies
just below the skull.
Middle ganglion lies at the level of the cricoid
cartilage (6th cervical vertebra).
Inferior ganglion may fuse with 1st thoracic to form
stellate ganglion and it lies in front of the neck of
the 1st rib.
Branches of superior ganglion
1.
2.
3.
4.
5.
6.
Internal carotid nerve: accompanies the internal
carotid artery and enters the carotid canal and
form the plexus around the artery.
Gray rami communicantes: to upper four anterior
rami of the cervical nerves.
Arterial branches: with form plexus around the
common and external carotid arteries and are
distributed with them.
Branches to the cranial nerves: join the
glossopharyngeal, vagus and hypoglossal nerves.
Pharyngeal branches: to the pharyngeal plexus.
Superior cardiac branch: to the cardiac plexus in
thorax.
Branches of middle ganglion
1.
2.
3.
4.
Gray rami communicantes: to the anterior rami
of the 5th and 6th cervical nerves.
Arterial branches: with form plexus around the
inferior thyroid artery to be distributed to the
thyroid gland.
Middle cardiac branch: to the cardiac plexus in
thorax.
Ansa subclavia: descends in front of the first part
of subclavian artery then rotates around it and
ascends again to join the inferior cervical (or
stellate) ganglion.
Branches of inferior ganglion
1.
2.
3.
4.
Gray rami communicantes: to the anterior
rami of the 7th and 8th cervical nerves.
Arterial branches: with form plexus
around the subclavian and vertebral
arteries to be distributed along them.
Inferior cardiac branch: to the cardiac
plexus in thorax.
Ansa subclavia: mentioned before.
Cervical plexus
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1.
2.
3.
Formed by the anterior rami of the upper cervical
nerves.
Lies in front of the origin of levator scapulae and
scalenus medius muscles.
It is covered by the prevertebral fascia.
Branches:
Cutaneous branches: lesser occipital, great auricular,
transverse cervical and supraclavicular nerves.
Muscular branches: to prevertebral muscles,
sternocleidomastoid & trapezius (proprioceptive),
levator scapulae, geniohyoid & thyrohyoid (through
C1 fibers that join hypoglossal nerve and infrahyoid
muscle (through ansa cervicalis).
Phrenic nerve: to the diaphragm.
Phrenic nerve
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It is the only motor nerve supply to the
diaphragm.
It also contains sensory and sympathetic nerves.
It supplies the pleura and peritoneum on both
surfaces of diaphragm, mediastinal pleura,
pericardium and proprioceptive sensation of the
diaphragm.
It arises from C3,4,5 and runs over the scalenus
anterior muscle (from its lateral to medial
borders) and covered by prevertebral fascia and
enters the thorax by passing in front of the
subclavian artery.