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Surgical anatomy of the neck
Developmental anatomy
First arch structures from the upper border of the neck. The mandible is derived from Meckel’s
cartilage. Mylohyoid ,anterior belly of digastric are also derived from first arch. Mandibular branch
of trigeminal nerve. First pouch endoderm froms tubotympanic recess which develops middle ear
cleft. Malleus & incus develop from first arch .
Second arch are formed from Reichart’s cartilage, they are formed styloid process, lesser cornu &
upper part of the body of hyoid bone. Muscles are platysma, posterior belly of digastrics &
stylohyoid. Facial nerve & stapes are developed from second arch.
The third arch contributes the greater cornu & inferior body of the hyoid bone. It contributes to the
hypobronchial eminence, which forms the cartilage of the epiglottis. It forms only muscle of the
neck, stylopharyngeus & glossopharyngeal nerve. Third pouch gives thymus & inferior parathyroid.
The descent of the thymus draws down the parathyroid III, so that it lies inferior to parathyroid IV.
Fifth arch completely absorbed.
The third & fourth arches fuse forming a transitory sinus called cervical sinus. If it is persist it runs in
the neck between internal & external carotid arteries to the apex of the pyriform fossa.
Fourth & six arches from the muscles & cartilages of the larynx ,muscles of the pharynx. Superior
laryngeal nerve & recurrent laryngeal nerve of the vagus. Fourth pouch gives rise to the superior
parathyroid (IV). Fifth pouch forms the ultimobranchial body from which parafollicular cells or C-cells
develop. Sixth pouch gives the intrinsic muscles of the larynx.
Surface anatomy
Mastoid
It represents the origin of the sternomastoid muscle. Anterior & inferior to the mastoid process, the
transverve process of the atlas can be palpated. Anterior to this transverse process, angle &
ascending ramus of the mandibule.
Mandibule
The superficial lobe of the submandibular gland can be palpated just inferior to the lower border of
the mandibule.
Hyoid bone
The body & greater cornu of the hyoid bone are important bony landmarks in the neck.
1. The greater cornu is just inferior to the angle of the mandibule.
2. The greater cornu acts as guide to lower extent of the course of the marginal mandibular
branch of the facial nerve.

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3. It divides node levels II & III.
Thyroid cartilage
Just inferior to the body of the hyoid bone is the thyroid cartilage. The thyrohyoid membrane links
the two. This cartilage can be moved over the cricoids cartilage when the resulting crepitus is a sign
of normality.
Cricoids cartilage
This can be palpated inferior to the thyroid cartilage in the midline. Between the two is the thyroid
cartilage in the midline. Between the two is the cricothyroid membrane. This has a spring like feel &
is the site of emergency tracheostomy. The cricoids is at the level of six cervical vertebra& represent
the boundary between larynx& trachea, & the pharynx & oesophagus.
Trachea
The cervical trachea can be palpated just inferior to the cricoids cartilage.
Thyroid gland
The isthmus can be palpated overlying the trachea between the second & third trachea rings. The
thyroid lobes lie deep to the sternocleidomastoid muscles & can not be palpated unless enlarged.
Sternocleidomastoid
This muscle arises from the mastoid process & divides into a tendinous sternal head & a fan-shaped
clavicular head. It divides the neck into anterior & posterior triangles. The posterior border is the
anterior boundary of the posterior triangle. Anterior border is the posterior border of the anterior
triangle. On its deep surface is the carotid sheath which includes the carotid arteries, internal jugular
vein, vagus nerve, the jugular chain of lymph nodes. This account for 80% of all lymph nodes inthe
neck. The jugular chain of lymph node is more easily palpated by tilting the head to the side that is
being examined. This relieves the tension on the muscles & allows the deep surface to be accessed.
Trapezius
This muscle can be palpated posterior to the sternomastoid. Elevating the shoulder against
resistance makes it more prominent.
Marginal mandibular branch of facial nerve
The lower limit of the nerve is the greater cornu of the hyoid bone,so that incision below this should
not damage the nerve.
Accessory nerve
This nerve runs through the sternocleidomastoid & in this part of its course is well protected. It exits
the posterior border of the sternocleimastoid at the junction of the upper & middle third about 1cm
above Erb’s point. This is the point at which the cervical plexus emerges from the posterior border of
the muscle. The nerve then course across the roof of the posterior triangle & enters the trapezius at
the junction of its middle & lower thirds in the neck.

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Carotid artery
This can be best palpated at the carotid bifurcation. This is between the angle of the mandibule &
the greater cornu of the hyoid bone. It follow a line from the sternoclavicular joint to midway
between the angle of the mandibule & mastoid tip.
Root of the neck
The manubrium, sternoclavicular joints & clavicles form the surface landmarks of the root of the
neck. The superior surface of the manubrium is the jugular notch & above this is the suprasternal
fossa or Burn’s space. Laterally , the clavicles articulates with the acromium forming the anterior
boundary of the root of the neck.
Triangles
It is difficult to readily compartmentalize anatomically all of the structures in the neck. To make this
easier, the neck has been classified divided into triangles. The sternocleidomastoid divides the neck
into anterior & posterior triangles( sternocleidomastoid itself is inneither triangle). The submental,
submandibular, carotid & muscular triangles divided the anterior triangles.
Anterior triangle
The boundaries of this triangle are anterior border of the sternomastoid, inferior ramus of the
mandibule & midline.
1)Submental triangle
The boundaries are the anterior belly of the digastrics, midline & hyoid bone. It contain lymph node
& sublingual gland.
2)Submandibular triangle
The boundaries are the inferior margin of the mandibule & anterior & posterior belly of the
digastrics muscles. The deep boundary consists of the stylohyoid & mylohyoid muscles. The
submandibular triangle contains the submandibular salivary gland, deep fascia, lymph node, anterior
facial vein, facial artery & marginal mandibular branch of the facial nerve.
3)Carotid triangle
The boundaries are the anterior border of sternomastoid, posterior belly of omohyoid & the
superior belly of omohyoid. It contains the upper carotid sheath & lymph node.
4)Muscular triangle
The boundaries are the lower anterior border sternomastoid, superior belly of omohyoid & hyoid
bone, the midline. It contain lower carotid sheath, infrahyoid muscles(strap muscles), upper
aerodigestive tract, thyroid & parathyroid gland.
Posterior triangle
The boundaries of the posterior triangle are posterior border of the sternmastoid,anterior boder of
the trapizeus & clavicle. It contains cervical & brachial plexus, lymph nodes, omohyiod muscles.
Occipital ,transverse cervical, suprascapular & subclavian vessels.

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1)Lateral neck triangle
The boundaries are the posterior border of the stenomastoid, anterior border of the trapezius &
superior border of the inferior belly of the omohyoid. It contain cervical plexus, accessory nerve &
lymph nodes.
2)Submandibular triangle
The boundaries are the lower border of the inferior belly of omohyoid, the clavicle, & posterior
border of the sternomastoid. It contain are fibrofatty tissue, the scalene muscles, the brachial plexus
& the subclavian vessels including thyrocervical trunk. Also included are Sibson’s suprapleural
fascia & the pleura.
The trapezius muscle covers the cervico-occipital region & represent the posterior neck. This area is
rarely involved in the head & neck surgery ,so will not be considered in detail.
Fascial layers
The identification of fascia & fascial planes allows dissection to be performed quickly & relatively
blood-lessly. The neck has a superficial & deep fascia. The deep fascia has three layers, a superficial
layer, middle or visceral layer & a deep layer. Fascia is investing fibrous tissue related to muscles &
major neck structures.
Superficial cervical fascia
This is thin layer that invests the platysma muscle. This fascia is penetrated by blood vessels that
supply the skin. The subplatysma flap therefore protects the blood supply to the skin.
Deep cervical fascia
1)Superficial or investing layer
This arise from the ligamentum nuchae & spinous processes of the cervical vertebrae & invest entire
neck. It splits to enclose the trapezius, the omohyoid, sternocleidomastoid, strap muscles, & the
parotid gland.
1. The superior attachment is to the external occipital protuberance, superior nuchal lines,
mastoid tip & zygomatic arch.
2. Anteriorly it is attached to the hyoid bone.
3. The inferior attachments are the acromium, the clavicle & sternum.
4. The superficial layer around parotid forms a thick layer which fuses with the fascia around
internal carotid artery. It also forms the stylomandibular ligament.
2) Carotid sheath
This is derived from the superficial layer of deep cervical fascia medial to the sternocleidomastoid
muscle;
1. It contains 80% of the lymph nodes of the neck.

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2. The carotid arteries
3. The internal jugular vein
4. Vagus nerve.
3)Middle layer/pretracheal or visceral layer:
this is derived from the superficial layer of the deep cervical fascia passes deep to the strap muscles
& encircles the trachea, thyroid, & oesophagus.
Movement of hyoid bone during swallowing elevates the fascia so that thyroid lumps
characteristically move on deglutition.
4) Deep layer or prevertebral fascia:
This is arises from the ligamentum nuchae & the spinous processes of the cervical vertebrae.it splits
to cnclose the prevertebral muscles,passes laterally around the scalene muscles & then forms a layer
over the vertebrae.
It forms the floor of the posterior triangles & allows the pharynx to glide during deglutition.
Neck spaces
Knowledge of these potential spaces is important in the understanding of the spread of infection &
tumours in the neck. They contain only loose areolar fascia.
1)Submental space; this is a midline space that lies between the anterior bellies of the digastrics
muscles.
2) Submandibular space: the superficial boundary is the submandibular gland & digastrics muscle.
The deep boundary is the mylohyoid muscle. It communicates with the floor of mouth around the
posterior border of the mylohyoid.
3) Peritonsillar space:
This lies between the tonsil & superior constrictor. It communicates through the fibres of the
superior constrictor with retropharyngeal space & parapharyngeal space.
4) Parapharyngeal space: this space is the most complex & clinically most important space. It is
shaped like an inverted pyramid, top of which is the base of the skull & inferior part is the greater
cornu of the hyoid bone. It is bounded medially by the superior constrictor & laterally by the
pterygoid muscles, mandibule & deep lobe of the parotid gland.
The parapharyngeal space is divided by the styloid process & its attachment into prestyloid &
poststyloid spaces. The prestyloid space contains ectopic salivary tissue, while poststyloid space
contains carotid arteries, internal jugular vein, cranial nerves 9 to 12, cervical sympathetic chain &
lymph nodes.
The parapharyngeal space contains a fat pad which is located centrally. The radiological
displacement pattern of this fat pad is useful for diagnosing lesions in this area. Prestyloid & lateral

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lesions will displace the fat pad posteromedially, while poststyloid lesions will displace this fat
anteriorly.
5) Retropharyngeal space: this sits between two parapharyngeal space & is continuous with both. It
superior boundary is skull base while the anterior boundary is the musculature of pharynx. The
posterior limit is the prevertebral fascia & the contents are only lymph nodes. It continues inferiorly
behind the oesophagus eventually communicates with the posterior mediastinum.
6) Pretracheal space: this lies anterior & lateral to the thyroid cartilage & deep to the strap muscles.
It contains the Delphian node & communicates with superior mediastinum.
7) Prevertebral space: this is the potential space that
lies between the cervical vertebrae & anterior longitudinal ligament posteriorly,
Prevertebral fascia anteriorly.
It extends down to the third thoracic vertebra where the fascia is bound to the vertebra. The
prevertebral fascia is thin & infections in this space can rupture directly through into the posterior
mediastinum.
Muscles
Sternocleidomastoid :
This is the most prominent & important muscle in the neck in relation to the surgery. Its inferior
attachment is onto sternum & clavicle. The sterna head is a thick tendon & the clavicular head is
muscular. Superior attachment is in the mastoid tip. Motor supply is the spinal accessory nerve &
anterior rami of cervical C2, 3, 4 segments provides sensory & proprioceptive function.
Trapezius
It has a wide origin from
1. medial third of the superior nuchal line,
2. ligamentum nuchae down to the seventh cervical vertebra,
3. all spinous processes & interspinal ligaments down to the 12th thoracic vertebra.
Insertion
1. the superior fibres insert into the clavicle & acromian,
2. inferior fibres from the thoracic vertebra insert into spine of the scapula.
Paralysis of trapizus is a common consequence of surgical damage to the accessory nerve in the
posterior triangle leading to malrotation of the scapula & traction on the brachial plexus which
leads to severe chronic neck pain.

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Omohyoid
This is one of the strap muscle. The proximal attachment is to the hyoid bone just lateral to the
attachment of sternohyoid.
As it course inferiorly, it diverges laterally, runs deep to the sternomastoid & crosses the internal
jugular vein at which point it becomrs tendon. It is an useful landmark for the internal jugular vein.
Lateral to the internal jugular vein, inferior belly of omohyoid develops, runs across the posterior
triangle.
Nerve supply is the ansa cervicalis, the function of this muscle is obscure.
Digastric
It arises from the digastrics ridge, which is on the medial aspect of the mastoid tip.
The posterior belly runs anteroinferiorly & becomes tendon which runs through a sling that is
attached to the lesser cornu of hyoid bone.
The anterior belly runs anterosuperiorly to insert into the digastrics fossa on the inner surface of
mandible.
It elevates the hyoid bone during swallowing & assitts the lateral pterygoid in opening the mouth.
Posterior belly is supplied by the facial nerve & anterior belly supplied by mandibular division of the
trigeminal nerve.
Strap muscles
This group of muscles comprises the sternohyoid, omohyoid, thyrohyoid& sternothyroid muscles.
They move the larynx & depress the mandibule. They are supplied by segmentally from C1 ,2 3 via
the ansa cervicalis.
Prevertebral muscles
The prevertebral muscles are a group of weak flexors that are bound down by the important
prevertebral fascia.
Cervical lymphatics
The cervical lymphatics are divided into superficial & deep. The superficial perforate the cervical
fascia & drain into the deep. When cancer involve, they will require skin resection for removal in an
extended neck dissection.
The deep lymphatic vessels & nodes are most densely associated with fascial condensations. This
means they are most commonly found around blood vessels, nerves, muscles. The deep lymphatics
drain the mucosa of the mouth, oropharynx, nasopharynx, larynx& hypopharynx.
Submental group
These nodes are situated in the midline, inferior to the mandibule & between the anterior bellies of
the digastrics muscles. They drain the anterior floor of the mouth.

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Submandibular nodes
These nodes are divided into six groups. They are preglandular, prevascular, retrovascular,
retroglandular intraglandular & deep nodes. These nodes can be described as those related to the
submandibular gland & those related to the facial vessels.
Cancer of the floor of the mouth, tongue & buccal cavity metastasis much more commonly to the
perivascular nodes which should be cleared in a neck dissection.
Jugular chain
80% of lymph node in the neck are closely associated with the internal jugular vein. The lymphatic
channels are found within the loose areolar tissue that exists around the internal jugular chain &
within the carotid sheath. The nodes occur anterior, posterior & lateral to the vein.
1) The most superior segment of the vein extends from the skull base to the level of the carotid
bifurcation which coincides with the level at greater cornu of the hyoid bone. Nodes found
here are referred to as the jugulodigastric nodes, deep to the digastrics muscle. They are
the first echelon node for the drain of the palatine tonsil.
2) Between the upper & middle jugular chain lie the junctional nodes. They represent a
lymphatic anastomosis of the submandibular nodes, the retropharyngeal nodes & jugular
chain of nodes.
3) The middle jugular nodes are found between the carotid bifurcation & the level at which the
omohyoid tendon crosses the internal jugular vein. They are first echelon nodes for the
larynx, mid hypopharynx & upper thyroid gland.
4) The lower jugular nodes are those between the tendon of the omohyoid & down to the
thoracic inlet. They are sometimes referred to as the prescalene group of nodes. They form
an important confluence between the mediastinal node group, the axillary group & the neck.
This communication can be a reason why neck nodes may appear secondary to disease
outside the neck.
Posterior nodes
The posterior triangle contains lymph nodes that are arranged into two groups: that are found along
the accessory nerve& those related to the thyrocervical vessels.
The nodes along the accessory nerve are the first echelon for the nasopharynx & second echelon for
the areas drained by the anterior neck nodes are related to the thyrocervical vessels.

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Lymph node levels
It is a system designed by surgeons & radiologist rather than anatomists & divides neck into six
levels, of which I to V are paired in the lateral neck, and levels VI describes midline neck nodes from
hyoid to sternal notch.
LEVEL I
This level refers to the submental & submandibular nodes & drains the lip, oral cavity & tongue.
Subzone Ia refers to the submental nodes & subzone Ib to the submandibular nodes. Subzone Ia
drains anterior floor of the mouth, lower lip & ventral tongue whereas subzone Ib drains other
subsites in the oral cavity.
LEVEL II
This form the upper jugular group of nodes & drains the oropharynx, larynx, hypopharynx & parotid.
The course of the accessory nerve divides this level into two subzones. Level IIa lies anteroinferior to
the spinal accessory & level IIb posterosuperior.
The IIb subzone is also known as the submandibular recess. It is clinically useful anatomical
differentiation because positive level IIa disease mandates IIb dissection. However elective
dissection for laryngeal & hypopharyngeal malignancy can exclude level IIb.
LEVEL III
This refers to the middle jugular nodes & drain larynx & pharynx.
LEVEL IV
Refers to lower jugular chain. This is small area which again drain the larynx & pharynx.
LEVEL V
This is posterior triangle group of nodes. The Va lies superior to the inferior belly to the omohyoid
muscles & the Vb level is inferior to the inferior belly of omohyoid. The Va area contains the chain of
nodes along the accessory nerve which drain the nasopharynx. The Vb level contains nodes related
to the thyrocervical trunk which drains the thyroid gland.
LEVEL VI
This is the anterior group or central group of nodes. This includes the paratracheal, perithyroidal &
Delphain nodes.
LEVEL VII
This corresponds to the superior mediastinal tissues. It is not recognized by most American texts.

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Major blood vessels
Common carotid artery
This arises from the brachiocephalic artery on the right & the arch of the aorta on the left. It usually
has no branches. Its surfaces markings are the sternoclavicular joint , the tubercle of the lateral
process of C6( Chassaignac’s tubercle)& bifurcates at the level of the greater cornu of the hyoid
bone. The important relationships are the internal jugular vein where common carotid artery runs
medial &deep, while the vagus nerve runs between the two in the carotid sheath. The sympathetic
trunk runs deep to the sheath.
Internal & external carotid artery
This division is usually at the level of the hyoid bone, although it may be higher but rarely lower.
Deep to the bifurcation is the carotid body, which is reddish-brown in colour & measures 6×3mm. It
contains glomus cells which containing dopamine & innervated by glossopharyngeal nerve.
At the level of division, the vessel dilates to form the carotid sinus. This may confined to the origin
of the internal carotid. Here media is thinner & adventitia thicker. Stretch receptors are innervated
by the glossopharyngeal nerve.
The internal carotid artery runs from the upper border of the thyroid cartilage to the carotid canal
in petrous temporal bone passing deep to the posterior belly of the digastrics muscle. It is normally
straight & unbranched, though 15% of cases it may be coiled or kinked. The internal jugular vein lies
anterolateral through the entire course of the internal carotid.
The external carotid artery originates with internal carotid artery. In children, it is much narrower
than internal carortid, but in adult the two are about the same size. It course in a straight line from
the greater cornu of the hyoid bone to a point between the mastoid & ascending ramus of
mandibule. It terminates in the substances of the parotid gland, the terminal branches are the
superficial temporal & maxillary artery. Before entering the deep surface of the the parotid gland,
the artery gives off six branches. They are from
1. anterior surface; superior thyroid, lingual, facial .
2. Deep branch is ascending pharyngeal, this arises just above the bifurcation of the common
carotid artery & is not seen during a neck dissection.
3. Posterior branches are the occipital, posterior auricular & runs superficial to the internal
jugular vein.
Ligation of the external carotid artery is a common procedure to control head & neck haemorrhage.
The external carotid artery is anterior & superficial to the internal carotid artery. The external
carotid also can be identified by recognizing more than one branch.
Internal jugular vein
The surface anatomy of the internal jugular vein in the neck is the lobule of ear to the medial end of
the clavicle running deep to the sternal & clavicular heads of the sternocleiodomastoid.

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Jugular vein is a continuation of the sigmoid sinus. It exists the skull in the posterior compartment of
the jugular foramen. At its origin exists the superior bulb which is deep to the floor of the tympanic
cavity. At its termination the internal jugular vein has an inferior bulb. The vein runs in the carotid
sheath & joins the subclavian vein to form brachiocephalic vein.
The thoracic duct joins the vein at the intersection with the subclavian in Chassaignac’s triangle
which is formed by the longus colli, scalenus anterior with subclavian artery at the base. The apex is
formed by the tubercle of the lateral process of C6(Chassaignac’s tubercle).
Nerves
Marginal mandibular nerve
This nerve runs inferior to the angle of the mandible,it dips down into the neck & runs superfiacial to
the submandibular triangle. The nerve deep to the platysma & is superficial to the deep fascia. It
runs inferior to the greater cornu of the hyoid bone, which is the inferior landmark of its course. It
curves upwards & crosses the mandible for a second time close to the facial vessels. It supplies the
angularis oris.
Glossopharyngeal nerve
It exists from the skull at the anterior compartment of the jugular foramen. It has an inferior
ganglion in the neck which contains cell bodies of the sensory fibres. It passes down on the internal
carotid artery then curves anteriorly around stylopharyngeus, deep to the hyoglossus & reaches the
tongue. It branches are
1. Tympanic branch( Jacobson’s nerve) ; which supplies sensation to the middle ear.
Parasympathetic supply to the parotid gland from inferior salivery nucleus via tympanic
plexus.
2. Motor supply to the stylopharyngeus.
3. Carotid sinus branch, it takes baroreceptor & chemoreceptor information to the brainstem.
4. Pharyngeal branches join the pharyngeal plexus.
5. Tonsillar branch supply the sensation to the tonsil mucous membrane
6. Lingual branches supply the posterior 1/3rd of the tongue.
Vagus nerve
It exists the skull base through the middle compartment of the jugular foramen. Beneath the skull
base, the nerve dilates to form the inferior ganglion which contains the afferent cell bodies.
Its branches are the
1. Auricular branch; Arnold’s nerve runs between the mastoid & tympanic plate to supply the
tympanic membrane & ear canal skin.
2. Carotid body branches

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3. Pharyngeal branches
4. Superior laryngeal branches
5. Cardiac branches
6. Recurrent branches; the left recurrent laryngeal nerve hooks around the ligamentum
arteriosum & arch of aorta & then runs cranially in the trachea-oesophageal groove. Right
usually runs around the subclavian artery before coursing medially towards the trachea-oesophageal
groove.
The relationship that the recurrent laryngeal nerves have with the inferior thyroid artery&
its branches is of great surgical significance during thyroidectomy. It may run deep, through
or superficial to the inferior thyroid artery its branches.
The common landmark for it is as the inferior side of Beahr’s triangle, with the other sides
being the common carotid artery & inferior thyroid vessels. It supplies the
trachea,oesophagus, hypopharynx & enters the larynx above the cricothyroid joint.
Spinal accessory nerve
The accessory nerve is formed in the posterior cranial fossa by the union of spinal & cranial parts.
The spinal part is formed by upper five cervical roots & run into the posterior cranial fossa via
foramen magnum. After uniting with the cranial root the nerve emerges from skull base through
middle compartment of the jugular foramen, lateral to the vagus nerve.
The cranial component peels off & joins the vagus just inferior to the inferior ganglion.
It supplies motor only to sternomastoid muscle from the C2 & C3 roots.
The accessory nerve exits sternomastoid muscles at the junction of the upper & middle thirds of the
posterior border, a point known as Erb’s point. It runs across the posterior triangle between deep &
superficial layer of the deep cervical fascia. The nerve enter the trapezius at the junction of its lower
& middle thirds. The trapezius muscle is supplied from C3 & C4 roots.
Hypoglossal nerve
This nerve exits the skull through the anterior condylar or hypoglossal canal, in the occipital bone.
Then it runs below the posterior belly of the digastrics along with external carotid artery upto the
greater cornu of the hyoid bone. It then courses upwards deep to the hyoglossus & divides to supply
all the intrinsic muscles of the tongue & all extrinsic muscles except the palatoglossus.
It gives the upper root of the ansa cervicalis. It passes between the internal jugular vein & internal
carotid artery & runs on the internal jugular vein. This fibres are derived from the C1 nerve root &
supply the strap muscles.
Cervical plexus
This is a plexus of nerves formed from the anterior rami of the upper four cervical nerves. It lies on
scalenus medius & deep to the prevertebral fascia.

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1) Ansa cervicalis: The muscular branches of the cervical plexus are a loop from C1 to the
hypoglossal nerve, peel off as a superior root of ansa cervicalis .Inferior root of the ansa
cervicalis which is formed from the union of branches from the C2 & C3 roots .
2) C2 & C3 which supply the sternomastoid muscle. C3 & C4 roots supply the trapezius muscle.
These branches mainly propriocetive.
3) Phrenic nerve(mainly C4) is an important muscular branch of the cervical plexus. It is only
motor supply of ipsilateral diaphragm. It is also sensory to the central tendon of the
diaphragm, pericardium & pleura.
4) Cervical plexus gives four cutaneous branches. They supply the front & side of the neck,
external ear, parotid gland & fascia. They emerge from behind the sternomastoid at Erb’s
point (at junction of upper 1/3rd & lower 2/3rd of the posterior border of sternomastoid).
They fan out to supply the neck. These branches are the lesser occipital, greater auricular,
transverse cervical & supraclavicular nerves.
Cervical sympathetic trunk
The fibre runs over the neck of the first rib & ascends to terminate in the superior ganglion. Inferior
ganglion is at the level of the first rib. Inferior ganglion fused with thoracic ganglion to form stellate
ganglion. The head & neck derive their supply from thoracic levels 1- 3.
Interruption of the cervical sympathetic trunk leads to Horner’s syndrome. This consist of ptosis,
myosis, anhydrosis, blocked nose.