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Root of the Neck
Head & Neck Unit – Lecture15
‫ حيدر جليل األعسم‬.‫د‬
Root of Neck
It is the area immediately superior
to upper thoracic aperture and
axillary inlet. It contains structures
passing between neck, thorax, and
upper limb.
It is bounded by:
Anteriorly: Top of manubrium and
superior margin of the clavicle
Posteriorly: Top of T1 thoracic
vertebra and superior margin of the
scapula to the coracoid process.
There is also an extension of the thoracic cavity projecting into the root
of the neck. This consists of an upward projection of the pleural cavity,
on both sides, and includes the cervical part of the parietal pleura
(copula), and the apical part of the superior lobe of each lung.
Muscles of Root of the Neck
Scalenus Anterior Muscle
It is key muscle of root of neck. It is
deeply placed & descends vertically
from vertebral column to first rib.
Origin: Transverse processes of 3rd,
4th, 5th & 6th cervical vertebrae
Insertion: 1st rib
Action: Elevates 1st rib; laterally
flexes & rotates cervical vertebrae.
Nerve Supply: C4, C5 & C6.
Important Relations
Anteriorly: carotid arteries, vagus
nerve, internal jugular vein, deep
cervical lymph nodes, Transverse
cervical, suprascapular arteries.
Prevertebral layer of deep cervical
fascia bind phrenic nerve to muscle.
Posteriorly: pleura, origin of
brachial plexus, second part of
subclavian artery & Scalenus medius
Medially: vertebral artery & vein &
sympathetic trunk. left side medial
border is related to thoracic duct.
Laterally: cervical plexus, roots of brachial plexus & third part of subclavian artery.
Root of Neck
Scalenus Medius
It lies behind scalenus
anterior and extends
from transverse process
of atlas and transverse
processes of next five
cervical vertebrae to be
inserted into upper
surface of first rib behind
the groove for subclavian
artery. It lies behind roots
of the brachial plexus and
subclavian artery.
Vessels at the root of Neck
Subclavian Arteries
Subclavian arteries on both sides arch
upwards out of thorax to enter root of neck
Right subclavian artery begins posterior to
sternoclavicular joint as one of two terminal
branches of brachiocephalic trunk. It arches
superiorly and laterally to pass anterior to
cervical pleural and posterior to anterior
scalene muscle. Continuing laterally across
the 1st rib, it becomes the axillary artery.
Left subclavian artery begins in thorax as a
direct branch of aortic arch. Lying posterior
to left common carotid artery & lateral to
trachea, it ascends & arches laterally, passing
anterior to cervical pleural and posterior to
anterior scalene muscle. Continuing laterally
across 1st rib, it becomes axillary artery.
Subclavian Arteries
Subclavian artery is divided into
three parts by anterior scalene :
First part: from origin of artery
to anterior scalene muscle;
Second part is the part posterior
to anterior scalene muscle;
Third part is the part lateral to
anterior scalene muscle before
lateral border of first rib.
All branches from right and left
subclavian arteries arise from the
first part.
Branches include vertebral artery, thyrocervical trunk, internal
thoracic artery & costocervical trunk.
Subclavian Veins
They begin at lateral margin of 1st
rib as continuations of axillary
veins. Passing medially on each
side, just anterior to anterior
scalene muscles, each subclavian
vein is joined by internal jugular
vein to form brachiocephalic veins.
The only tributary to subclavian
veins are external jugular veins.
Autonomic Nervous System of Head & Neck
Sympathetic Part: Cervical Sympathetic Trunk
Cervical part of sympathetic trunk extends upward to base
of skull and below to neck of 1st rib, where it becomes
continuous with thoracic sympathetic trunk.
It lies directly behind internal & common carotid arteries &
is embedded in deep fascia between carotid sheath &
prevertebral deep fascia.
It has 3 ganglia:
1.Superior Cervical Ganglion: lies immediately below skull
Branches:
Internal carotid nerve: (internal carotid artery- Plexus)
Gray rami: (upper four anterior rami of cervical nerves)
Arterial branches: (common & external carotid aa. Plexus)
Cranial nerve branches: 9th, 10th & 12th cranial nerves
Pharyngeal branches: join pharyngeal branches of
glossopharyngeal & vagus n. & form pharyngeal plexus.
Superior cardiac branch: ends in cardiac plexus in thorax.
Autonomic Nervous System of Head & Neck
2. Middle Cervical Ganglion: lies at level of cricoid
Branches:
Gray rami: (ant. rami of 5th & 6th cervical nerves)
Thyroid branches: along inferior thyroid artery.
Middle cardiac branch: ends in cardiac plexus.
3. Inferior Cervical Ganglion: fused with 1st
thoracic ganglion to form stellate ganglion. It lies in
interval between transverse process of C7 & neck
of 1st rib.
Branches:
Gray rami: (ant. rami of 7th & 8th cervical nerves
Arterial branches: subclavian & vertebral arteries
Inferior cardiac branch: join cardiac plexus.
Sympathetic trunk connecting middle cervical
ganglion to inferior or stellate ganglion is
represented by two or more nerve bundles. The
most anterior bundle crosses in front of 1st part of
subclavian artery and then turns upward behind it.
This anterior bundle is called ansa subclavia.
Parasympathetic Part
Parasympathetic part of autonomic nervous system is
located in nuclei of oculomotor (3rd), facial (7th),
glossopharyngeal (9th), and vagus (10th) cranial nerves.
Axons from these nuclei are myelinated preganglionic
fibers and synapse in peripheral ganglia located close
to viscera they innervate. Cranial parasympathetic
ganglia are ciliary, pterygopalatine, submandibular &
otic. The postganglionic fibers are nonmyelinated, and
they are short in length.
Lymphatics of Neck
They include superficial nodes around the
head, superficial cervical nodes along
external jugular vein & deep cervical nodes
forming a chain along internal jugular vein.
Superficial lymph nodes around the head
5 groups of lymph nodes form a ring around
head and are primarily responsible for
lymphatic drainage of face & scalp. Their
pattern of drainage is very similar to area of
distribution of arteries near them.
1. Occipital nodes near attachment of
trapezius muscle to skull and associated with
occipital artery.
2. Mastoid nodes (retroauricular / posterior
auricular nodes) posterior to ear near
attachment of sternocleidomastoid and
associated with posterior auricular artery.
3. Pre-auricular & Parotid nodes anterior to
ear & associated with superficial temporal &
transverse facial artery.
4. Submandibular nodes inferior to body of
mandible and associated with facial artery.
5. Submental nodes inf. & post. to the chin.
Lymphatic flow:
Drainage from occipital & mastoid LN= to superficial cervical nodes along external jugular vein;
Drainage from pre-auricular & parotid, submandibular & submental LN= to deep cervical nodes.
Root of Neck
Superficial cervical lymph nodes:
They lie along external jugular vein on
superficial surface of sternocleidomastoid muscle. They primarily receive
lymphatic drainage from posterior and
posterolateral regions of scalp through
occipital & mastoid nodes.
Deep cervical lymph nodes
They form a chain of LNs along internal
jugular vein. They are divided into
upper & lower groups by intermediate
tendon of omohyoid muscle. The most
superior node in upper deep cervical
group is jugulodigastric node. Another
large node at or just inferior to
intermediate tendon of omohyoid
muscle, is jugulo-omohyoid node. This
receives lymphatic drainage from the
tongue. They eventually receive all
lymphatics of head & neck.
End of the Lecture
GOOD LUCK