Download Anterior jugular vein

Anatomy of neck
Dr. Muslim Kandel
2016
Surface anatomy
Skin
Superficial fascia
Anatomy of neck
platesma muscle
cutenous br of cervical plexus
superfecial veins
Deep fascia
Investing f , pretrachial f ,Carotid sheath , Prevertebral f ,Parotid f
,Pharyngo-basilar f ,Bucco-pharyngial f , supraplural membrane, legementum
nuchae
Muscular triangles
Ant. Triangle(sub divided into small triangles)
Post. Triangle(sub divided into small triangles)
Glands
Salivary glands
Thyroid & parathyroid glands
Superficial Fascia
The superficial fascia of the neck forms a thin layer that encloses the
platysma muscle. Also embedded in it are the cutaneous nerves
the superficial veins, and the superficial lymph nodes.
Platysma
Its important muscular sheet embedded in the superficial fascia
Origin :fascia covering pectorals major & deltoid
Insertion: lower border of mandible &skin of face
Nerve supply :-cervical br. of facial N
Action:-wrinkle of skin of neck
-depress of mandible
Superficial Veins
1-External Jugular Vein
begins just behind the angle of the mandible by the union of the
posterior auricular vein with the posterior division of the
retromandibular vein. It descends obliquely across the
sternocleidomastoid muscle and,
drains into the subclavian vein
Branches
-Posterior auricular vein
-Posterior division of the retromandibular vein
-Transverse cervical vein
-Suprascapular vein
-Anterior jugular vein
EXTERNAL JUGUAR VEIN
Superficial temporal v.
Maxillary v.
Facial v.
Posterior auricular v.
External jugular v.
Retromandibular v.
Common facial v.
(to IJV)
Transverse cervical v.
Suprascapular v.
Subclavian v.
Anterior jugular v.
jugular arch
2-Anterior Jugular Vein
--Formed just below the chin, by the union of
several small veins .
It runs down the neck close to the midline. Just
above the suprasternal notch, the veins of the
two sides are united by a transverse trunk
called the jugular arch.
--drain into the external jugular vein
Cutaneous nerves of neck
Arse from branches of cervical plexus
Lesser occipital n from ant. Rami of C2  supply upper
part of skin of inner surface of auricle & adjescent
part of skin of scalp
Greet auricular n from ant. Rami of C2,C3 supply lower
part of skin of inner surface of auricle , skin over
parotid gl & skin over angle of mandible
Supraclavicular n from C3, C4  supply skin of post.
Triangle , skin of tip of shoulder& skin of chest down to
2nd rib
Transverse nerve of neck from C2,C3  supply of skin of
ant. triangle
Cutaneous nerves
Lesser occipital n.
External jugular vein
Greet auricular n.
Transverse nerve of neck
Anterior jugular vein
Supraclavicular n.
Superficial Lymph Nodes
Its lie along the external jugular vein superficial
to the sternocleidomastoid muscle
- receive lymph vessels from the occipital and
mastoid lymph nodes
- drain into the deep cervical lymph nodes
Deep Cervical Fascia
Its supports the muscles, the vessels, and the
viscera of the neck .
In certain areas, it is condensed to form welldefined, fibrous sheets called the
investing layer,
the pretracheal layer,
the prevertebral layer.
It is also condensed to form the carotid sheath
Investing fascia
Retropharyngeal space
Pretracheal fascia *
Buccopharyngeal fascia *
Carotid sheath
Common carotid a.
Internal jugular v.
Vagus n.
Prevertebral fascia
* = Component of visceral fascia
Investing Layer
Its is a thick layer that encircles the neck.(like collar ) It splits to enclose
the trapezius and the sternocleidomastoid muscles.its form base of
ant. & post. Triangles
Attachment –postlegemantum nuchae
--ant. hyoid bone , thyroid cartlage ,
--inf.  maniberium , clavicle , acromian processes & spin
of scapula
-- sup mandible , then splite to involve parotid gland
to attached to ext. audetory meatus
Pretracheal Layer
It is a thin layer that is attached above to the laryngeal cartilages It
surrounds the thyroid and the parathyroid glands, forming a sheath
for them, and encloses the infrahyoid muscles.
Prevertebral Layer
The prevertebral layer is a thick layer that
passes like a septum across the neck
-- behind the pharynx and the
esophagus
-- in front of the prevertebral muscles and
the vertebral column ,extend from base
of skull
to 3rd Thoracic vertebrate.
--It forms the fascial floor of the
posterior triangle,
-- it extends laterally over the first rib
cross scalenous ant. into the axilla to
Axillary Sheath
All the anterior rami of the
cervical nerves that emerge in
the interval between the scalenus
anterior and scalenus medius
muscles lie at first deep to the
prevertebral fascia.
As the subclavian artery and the brachial plexus
emerge in the interval between the scalenus anterior
and the scalenus medius muscles, they carry with them
a sheath of the fascia, which extends into the axilla and
is called the axillary sheath
Parotid f
Its derived from investing f
superficial layer  attach to zygomatic arch
Deep layer  attach to petrous ,temporal, styloid and
mastoid
Pharyngo –basilar f
Tough f connect pharynx to base of skull 
nasopharynx patent
Bucco-parhngial f
Cover muscles of pharynx
Supra plural membrane
Cover apex of lung
Base of skull
Buccopharyngeal fascia
Retropharyngeal space
Prevertebral fascia
Mediastinum
Ligamentum Nuchae
Strong Triangalar leg.
Its upper continuation of
supraspinus & infraspinus leg
Attachement
Above (base)occipital
protrberance and crest
below (apex)spine of C7
Ant. all cervical spines
Post. free
Clinical Significance of the Deep Fascia of the
Neck
Acute Infections
Dental infections
lower molar teeth. The infection spreads medially from the mandible
into the submandibular spaces and pushes the tongue forward and
upward. Further spread downward may lead to edema of the vocal
cords and airway obstruction.
Ludwig's angina is an acute infection of the submandibular fascial space
and is commonly secondary to dental infection
Chronic Infection
Tuberculous TB of the deep cervical lymph nodes can result in
liquefaction and destruction of one or more of the nodes. collarstud abscess. The clinician is aware of the superficial abscess but
must not forget the existence of the deeply placed abscess
Muscular Triangles of the Neck
Generally the neck divided into
2 large triangles ant. & post.
Triangles by
sternomastoid muscle
Anterior Triangle
bounded
above by the body of the mandible
posteriorly by the sternocleidomastoid
anteriorly by the midline .
roof :……formed by:
platysma
investing layer of deep cervical fascia
It is further subdivided by :
digastric anterior and posterior bellies into
,
the submental triangle,
the digastric triangle
omohyoid superior belly into
the carotid triangle
the muscular triangle
Posterior Triangle
bounded
posteriorly by the trapezius muscle,
anteriorly by the sternocleidomastoid
muscle,
inferiorly by the clavicle .
It is further subdivided by the
inferior
belly of the omohyoid muscle into :---a large occipital triangle above
--- a small supraclavicular triangle
below
roof ………formed by :
platysma •
investing (superficial) layer
of deep
cervical fascia.
floor :…….formed by : •
splenius capitis
levator scapulae muscles
anterior, middle, posterior
scalene muscles
Contains of post triangle:
accessory nerve,
cutaneous branches of cervical plexus,
external jugular vein,
transverse cervical
suprascapular vessels,
subclavian vein & artery,
Inferior belly of omohyoid,
roots and trunks of brachial plexus.
nerve to subclavius
dorsal scapular,
suprascapular,
long thoracic nerves
Sternocleidomastoid Muscle
When the sternocleidomastoid muscle contracts, it appears as an
oblique band crossing the side of the neck from the sternoclavicular
joint to the mastoid process of the skull.
Relation
It divides the neck into anterior and posterior triangles .
Post carotid arteries, the internal jugular vein, and the deep
cervical lymph nodes; it also overlaps the thyroid gland.
The deep surface of the posterior border is related to the cervical
plexus of nerves, the phrenic nerve, and the upper part of the brachial plexus
Ant skin, fascia, the platysma muscle, and the external jugular vein.
.
The origin have 2 heads
Manubrium sterni
medial third of clavicle,
insertion Mastoid process of temporal bone and occipital bone ,
nerve supply Spinal part of accessory nerve and C2 and 3,
Action Two muscles acting together extend head and flex neck; one muscle rotates
head to opposite side .
TRAPEZIUS MUSCLE
Origin: Superior nuchal line, ext.
occipital protuberance, lig.
nuchae, spines of C7 – T12
Insertion: Lateral 1/3 of clavicle,
acromion, spine of scapula
Functions:
--elevation of scapula (sup.
fibers),
depression of scapula (inf.
fibers),
retraction of scapula (middle
fibers),
superior rotation of glenoid fossa
of scapula (sup. + inferior fibers).
Scalenus Anterior Muscle
The scalenus anterior muscle is a key muscle in
understanding the root of the neck .It is deeply
placed and it descends almost vertically from the
vertebral column to the first rib.
Origin Transverse processes of third, fourth, fifth,
and sixth cervical vertebrae
Insertion First rib
Nerve supply C4, 5, and 6
Action Elevates first rib; laterally flexes and rotates
cervical part of vertebral column
SCALENE MUSCLES
Anterior scalene m.
Middle scalene m.
Posterior scalene m.
Rib 1
Important Relations
Anteriorly: Related to the carotid arteries, the vagus nerve, the
internal jugular vein, and the deep cervical lymph nodes .The
transverse cervical and suprascapular arteries and the
prevertebral layer of deep cervical fascia bind the phrenic nerve
to the muscle.
Posteriorly: Related to the pleura, the origin of the brachial plexus,
and the second part of the subclavian artery .The scalenus
medius muscle lies behind the scalenus anterior muscle.
Medially: Related to the vertebral artery and vein and the
sympathetic trunk . On the left side, the medial border is related
to the thoracic duct.
Laterally: Related to the emerging branches of the cervical plexus,
the roots of the brachial plexus, and the third part of the
subclavian artery
Scalenous medius
Largest of all scalenous m
Origin :post tubercle of all C. vertebrae
Insertion : 1st rib behind subclavian groove
N. supply:all cervical nn
Action flexion of neck &fixation of1st rib
Scalenous post.
Smallest of all scalenous
Scalenous minimous
v. Small m arise from transverse process of C7 inserted at plural
memberan
Nerves in posterior triangle
1-Cervical
plexus
2-Brachial plexus
1- four muscular branches
Roots , trunks and their
branches
2- four cutaneous
branches
1- dorsal scapular nerve –
c5(nerve to rhomboids )
2- nerve to subclavius – c5
&c6
3- nerve to serratus anterior –
c5,6 &7
Suprascapular nerve –c5&6
3- spinal root of
accessory nerve
(11th cranial nerve
)
It is the most
important structure in
the occipital triangle
Digastric & submandibular trianglar
boundaries
Above
….lower border of mandible
Below & infront
..anterior belly of Digastric muscle
Below & behind
..posterior belly of Digastric & stylohyoid muscles .
Floor :
Anteriorly : ……..mylohyoid muscle
Posteriorly ………part of hyoglossus muscle
Contents of Digastric triangle
submandibular salivary gland
submandibular lymph nodes
lie on the surface of the gland
facial artery
deep to posterior end of submandibular salivary gland
facial vein
lies superficial to submandibular salivary gland
hypoglossal nerve
nerve to mylohyoid muscle
digastric muscle
consists of two muscular bellies united by an intermediate rounded tendon.
Posterior belly
longer than the anterior belly,
arises from the mastoid notch
Insertion at Intermediate tendon is held to hyoid by fascial sling
Nerve supply Facial nerve
Anterior belly
Arise from Body of mandible have same insertion at Intermediate tendon is
held to hyoid by fascial sling s held in connection with the side of the body
and the greater cornu of the hyoid
N supply Nerve to mylohyoid
Action of both belly Depresses mandible or elevates hyoid bone
Mylohyoid muscle
is a paired muscle , flat and triangular, and is situated immediately
superior to the anterior belly of the digastric muscle running from the
mandible to the hyoid bone, forming the floor of the oral cavity of the
mouth
arise from the mandible at the mylohyoid line, (which extends from the
mandibular symphysis in front to the last molar tooth behind)
Insertion
--The posterior fibers pass inferomedially and insert at anterior surface
of the hyoid bone.
-- The medial fibres of the two mylohyoid muscles unite in a midline
raphe (where the two muscles intermesh)
N supply branch of the mandibular nerve through inf . Alvolaer N
Function its elevates the hyoid and the tongue. & support of floor of
mouth This is particularly important during swallowing and
speaking
Mylohyoid muscle
Geniohyoid
Its small muscle deep ( above) to mylohyoid m
Arise from Inferior mental spine of mandible
Inserted Body of hyoid bone
N supply First cervical nerve
Function Elevates hyoid bone or depresses
mandible
Genoglossus muscle
Between genial tubercle and tongue
Styloglossus muscle
from styloid process to the tongue
Hyoid bone
The hyoid bone (lingual bone)
The hyoid bone is U shaped and consists of a body and two greater and two
lesser cornua , unlike other bones, not articulate to other bones by
muscles or ligaments. The hyoid is anchored by muscles from all directions,
situated in the anterior midline of the neck between the chin and the
thyroid cartilage . At rest, it lies at the level of the base of the mandible in
the front and the (C3) behind.
attachment
-to the skull by the stylohyoid ligament
- to the thyroid cartilage by the thyrohyoid membrane.
-forms a base for the tongue and is suspended in position by muscles that
connect it to the mandible, to the styloid process of the temporal bone,
to the thyroid cartilage, to the sternum, and to the scapula
function is aids in tongue movement and swallowing.
The hyoid bone provides attachment to the muscles of the floor of the
mouth and the tongue above, the larynx below, and the epiglutis and
pharynx behind.
Styloid process
Is a slender projection of variable length
extends downward & forward from temporal bone.
Gives origin to :
A- three muscles:
stylohyoid,
styloglossus,
Stylopharyngeus
B-two ligaments :
stylohyoid
stylomandibular.
Carotid triangle
boundary :
Behind : …………..sternomastoid muscle
Infront & above : posterior belly of digastric muscle
Infront&below : superior belly of omohyoid muscle
Floor :
infont : hyoglossus muscle ( above ) and the thyrohyoid
muscle (below)
Behind: the middle constrictor muscle of the pharynx
(above ) and the inferior constrictor muscle of the
pharynx (below )
Carotid Sheath
The carotid sheath is a local condensation of the prevertebral, the pretracheal, and the
investing layers of the deep fascia
Attached - above At base of skull surround caroted &jagular foramens
- below blend with adventecia of arch of aorta
Contents :- its surround the
a- in the upper part(above post belly of digastric m)
internal carotid artery
the internal jugular vein,
4 cranial NN (9,10,11,12 )
deep cervical lymph nodes .
b-in the lower part (below post belly of digastric m)
.common internal carotid arteries
the internal jugular vein,
Vegus between CCA&IJV)
Note:-- sympathetic chain embeded in post layer of sheath
-- 2 limbs of ansa cervicalis at ant. Wall
-- sheath thick over art. While thin over vein
Contents of the Carotid triangle
1- The carotid sheath and its contents :
2- the external carotid artery :gives most of its
branches in the carotid triangle ( superior thyroid
artery ,lingual artery ,facial artery , ascending
pharyngeal artery and occipital artery )
3- hypoglossal nerve
4- Descendes cervicalis (C2,3) anterior to carotid
sheath.
5- sympathetic trunk adherent to the posterior wall
of carotid sheath
the Submental triangle
boundaries
Posterior (to the back) by the anterior belly of the
digastricus,
Anterior (to the front) by the midline of the neck
between the mandible and the hyoid bone;
Inferior (below) by the body of
the hyoid bone
floor is formed by the mylohyoid.
Contents of the Submental triangle
1- submental lymph nodes
2- beginning of the anterior jugular vein
Suprahyoid muscles
1- digastric muscle
2- mylohyoid muscle
3- hyoglossus muscle
4- geniohyoid muscle
5- stylohyoid muscle
The hyoglossus
Its thin and quadrilateral muscle
, arises from the side of the body
of hyoid bone and from the whole
length of the greater cornu,
and passes almost vertically
upward to enter the side of the
tongue, between the styloglossus
and the inferior longitudinal
muscle of the tongue.
It forms a part of the floor of
submandibular triangle
Relations of hypogossus
medial/deep
the glossopharyngeal nerve (cranial nerve 9)
the stylohyoid ligament
the lingual artery and vein.The lingual vein passes medial to the hyoglossus, and
the lingual artery passes deep to the hyoglossus.
Laterally, in between the hyoglossus muscle and the mylohyoid muscle lay
several important structures (from upper to lower): sublingual gland,
submandibular duct,
lingual nerve,
vena comitans of hypoglossal nerve,
the hypoglossal nerve.
Note, posteriorly, the lingual nerve is superior to the submandibular duct and a
portion of the submandibular salivary gland protrudes into the space between
the hyoglossus and mylohyoid muscles
Geniohyoid
muscle
Hyoglossus
Submendibular gland
Digastric
Accessory n.
Hypoglossal n.
Superior thyroid a.
Ansa cervicalis
Sternothyroid
Sternohyoid
Vagus n.
Cervical plexus
Phrenic n.
Omohyoid
The Styloglossus
the shortest and smallest of the three styloid muscles,
arises from the anterior and lateral surfaces of the styloid process near its apex,
and from the stylomandibular ligament.
Insertion Passing downward and forward between the internal and external
carotid arteries, it divides upon the side of the tongue near its dorsal surface,
blending with the fibers of the Longitudinalis inferior in front of the
Hyoglossus; the other, oblique, overlaps the Hyoglossus and decussates with
its fibers.
N supply the Hypoglossal nerve (CN XII) like all muscles of the tongue except
palatoglossus which is innervated by the Pharyngeal plexus of vagus nerve
Action draws up the sides of the tongue to create a trough for swallowing. As a
pair they also aid in retracting the tongue
The geniohyoid muscle
is a narrow muscle situated superior to the medial border of the
mylohyoid muscle
It arises from the inferior mental spine, on the back of the mandibular
symphysis,
insertion its runs backward and slightly downward, to be inserted into
the anterior surface of the body of the hyoid bone
N supply The geniohyoid muscle is innervated by fibres from the first
cervical nerve travelling alongside the hypoglossal nerve.These
fibers are called ansa cervicalis.
Action its brings the hyoid bone forward and upwards. This dilates the
upper airway, assisting respiration.
submandibular glands
The paired submandibular glands are major salivary glands located
beneath the floor of the mouth. At diagastric triangle
--wedge shape about 15 gr and produce 60–67% of saliva secretion;
Its divided into superficial (large) and deep lobes ( small), which are
separated by the mylohyoid muscle ,together continue at post . free
border of mylohyoid
submandibular duct arise from medial surface of superfecial lobe
about 5 cm length, The excretory ducts are then crossed by the
lingual nerve, and ultimately drain into the sublingual caruncles on
either side of the lingual frenulum a
Blood supply. is supplied by sublingual and submental arteries
branches from the facial and lingual arteries
drained by common facial and lingual veins
The lymphatics drain into submandibular LN and subsequently into
jugulo - digastric lymph nodes
Nerve supply
Sensery N from lingual N through ganglion without relay while
Secretmotor regulated directly by the parasympathetic and indirectly by the
sympathetic (through arterial supply).
Parasympathetic is provided by the superior salivatory nucleus via the chorda
tympani, a branch of the facial nerve, that becomes part of the trigeminal
nerve's lingual nerve prior to synapsing on the submandibular ganglion.
-Increased parasympathetic activity promotes the secretion of saliva.
The sympathetic
--through the arteries that supply it. Increased sympathetic activity 
vasoconsitructionreduces bloodflowdecreasing the volume of secretions,
producing an enzyme rich mucous saliva.
-- direct stimulation of sympathetic nerves will cause an increase in salivary
enzymatic secretions. In sum, the volume decreases
Note:- The submandibular gland accounts for 80% of all salivary duct calculi
because viscous nature of the saliva that it produces and the tortuous travel of
the submandibular
Sublingual gland
They are the smallest, most diffuse, and the only unencapsulated major
salivary glands. They provide only 3-5% of the total salivary volume
They lie anterior to the submandibular gland inferior to the tongue, as
well as beneath the mucous membrane of the floor of the mouth
They are drained by 8-20 excretory ducts called the ducts of Rivinus
N supply :- branches from lingual N containing sensory fibers ,
sympathetic &parasympathetic f
blood supply sublingual and submental arteries.
Lymph drainage  the sublingual salivary gland drains into the
submandibular LN
the Muscular triangle
is bounded
in front, by the median line of the neck from the hyoid bone to the sternum;
behind, by the anterior margin of the sternocleidomastoid;
above, by the superior belly of the omohyoid
Contents
A-infrahyoid muscles
They consist of 4 muscles arranged into
2 layers :
1- superficial layer :
-- sternohyoid
-- omohyoid
2- deep layer:
-- sternothyroid
-- thyrohyoid
B-lat. Lobe of thyroid gl .leing deep
tosternohyoid &sternothyroid
sternohyoid
Origin : back of maniberium & back of clavicle
Insertion :- lower border of hyoid bone along
midline
N supply :-ansa cervicalis
Action :1-depresion of hyoid bone after deglutision
2-fixation of hyoid bone during movement of
tongue
omohyoid
Origin :- it has 2 bellis
1-sup. Belly —lower border of hyoid body lat. To
sternohyoid
1-inf. Belly –upper border of scapula
&suprascapular leg
Insertion :-intermediate tendon lies on IJV &held in
position by facial sling connect it to clavicle
N supply ansa cervicalis
Action like sternohyoid & pull deep facia around
Ext. J V
sternothyroid
Origin back of memberain & costal cartlage
Insertion Oblique line on lamina of thyroid
cartilage
N supply Ansa cervicalis; C1, 2, and 3
action Depresses larynx in second phase of
diglution
thyrohyoid
Origin :- Oblique line on lamina of thyroid
cartilage
Insertion :-Lower border of body of hyoid bone
N supply 1st cervical n C1(hypoglusal n)
action Depresses hyoid bone or elevates larynx
•
Ansa cervicalis
Its nerve loop formed of 2 descending nn & supply 3 infrahyoid
mm
Site :- lies infront of carotid sheath
Formation : its formed by union of 2 descending nn
1-descending hypoglussi( sup . Limbe of ansa )
Its fibers aris from C1 join hypoglussal n then leave it its turn
forwareds across carotid sheath
20 descending cervicalis ( inf. Limb of ansa):
Its fiber arise from C2,3 its began behind IJV then descend along
its ant. Surface to join descending hypoglussi infront caroted
sheath( thus the ansa cervicalis arise from C1,2 ,3)
Branches of ansa cervicalis
Aris from convixity of loop and supply 3 of •
infrahyoid mm (the two belly of omohyoid
,sterno hyoid &sternothyroid)except
thyrohyoid (from C1 through hypoglossal n)
Cervical Ligaments
Stylohyoid ligament: Connects the styloid process
to the lesser cornu of the hyoid bone
Stylomandibular ligament: Connects the styloid
process to the angle of the mandible
Sphenomandibular ligament: Connects the spine of
the sphenoid bone to the lingula of the mandible
Pterygomandibular ligament: Connects the
hamular process of the medial pterygoid plate to
the posterior end of the mylohyoid line of the
mandible. It gives attachment to the superior
constrictor and the buccinator muscles
Thyroid Gland
Its largest endocrine gland in body about 25 gr
The thyroid gland butterfly in shape
consists of right and left lat. lobes connected by a narrow isthmus
at mid ant. Triangle . pyramidal lobe is often present, and it projects upward
from the isthmus, usually to the left of the midline.
A fibrous or muscular(levator glandulae thyroideae) band
frequently connects the pyramidal lobe to the hyoid bone
Capsules :1- true capsule adherent to gland
2- false capsule derived from the pretracheal layer of deep fascia.
The sheath attaches the gland to the larynx and the trachea. So
thyroid move with deglutition
Each lobe is pear shaped, with its apex being directed upward as far as the
oblique line on the lamina of the thyroid cartilage; its base lies below at the level
of the fourth or fifth tracheal ring.
The isthmus extends across the midline in front of the second, third, and fourth
tracheal rings
Relations of the Lobes
Anterolaterally: The sternothyroid, the superior belly of the omohyoid, the
sternohyoid, and the anterior border of the sternocleidomastoid (Fig. 11-49)
Posterolaterally: The carotid sheath with the common carotid artery, the internal
jugular vein, and the vagus nerve (Fig. 11-49)
Medially: The larynx, the trachea, the pharynx, and the esophagus. Associated with
these structures are the cricothyroid muscle and its nerve supply, the external
laryngeal nerve. In the groove between the esophagus and the trachea is the
recurrent laryngeal nerve (Fig. 11-49).
The rounded posterior border of each lobe is related posteriorly to the superior and
inferior parathyroid glands (Fig. 11-110) and the anastomosis between the
superior and inferior thyroid arteries.
Relations of the Isthmus
Anteriorly: The sternothyroids, sternohyoids, anterior jugular veins, fascia, and skin
Posteriorly: The second, third, and fourth rings of the trachea
The terminal branches of the superior thyroid arteries anastomose along its upper
border.
Blood Supply
The arteries to the thyroid gland are the superior thyroid artery, the inferior thyroid artery,
and sometimes the thyroidea ima. The arteries anastomose profusely with one another
over the surface of the gland.
The superior thyroid artery, a branch of the external carotid artery, descends to the upper
pole of each lobe, accompanied by the external laryngeal nerve (Fig. 11-110).
The inferior thyroid artery, a branch of the thyrocervical trunk, ascends behind the gland to
the level of the cricoid cartilage. It then turns medially and downward to reach the
posterior border of the gland. The recurrent laryngeal nerve crosses either in front of or
behind the artery, or it may pass between its branches.
The thyroidea ima, if present, may arise from the brachiocephalic artery or the arch of the
aorta. It ascends in front of the trachea to the isthmus (Fig. 11-110).
The veins from the thyroid gland are the superior thyroid, which drains into the internal
jugular vein; the middle thyroid, which drains into the internal jugular vein; and the
inferior thyroid (Fig. 11-110). The inferior thyroid veins of the two sides anastomose with
one another as they descend in front of the trachea. They drain into the left
brachiocephalic vein in the thorax.
Lymph Drainage
The lymph from the thyroid gland drains mainly laterally into the deep cervical lymph nodes. A
few lymph vessels descend to the paratracheal nodes.
Nerve Supply
Superior, middle, and inferior cervical sympathetic ganglia
Functions of the Thyroid Gland
The thyroid hormones, thyroxine and triiodothyronine, increase the metabolic activity of most
cells in the body. The parafollicular cells produce the hormone thyrocalcitonin, which
lowers the level of blood calcium
Parathyroid Glands
Location and Description
The parathyroid glands are ovoid bodies measuring about 6 mm long in their greatest
diameter. They are four in number and are closely related to the posterior border of the
thyroid gland, lying within its fascial capsule .
The two superior parathyroid glands are the more constant in position and lie at the level of
the middle of the posterior border of the thyroid gland.
The two inferior parathyroid glands usually lie close to the inferior poles of the thyroid gland.
They may lie within the fascial sheath, embedded in the thyroid substance, or outside the
fascial sheath. Sometimes they are found some distance caudal to the thyroid gland, in
association with the inferior thyroid veins, or they may even reside in the superior
mediastinum in the thorax.
Blood Supply
The arterial supply to the parathyroid glands is from the superior and inferior thyroid arteries.
The venous drainage is into the superior, middle, and inferior thyroid veins.
Lymph Drainage
Deep cervical and paratracheal lymph nodes
Nerve Supply
Superior or middle cervical sympathetic ganglia
Thyroid gland
Arteries of the Head and Neck
Common Carotid Artery
The right common carotid artery arises from the brachiocephalic artery behind the right
sternoclavicular joint (Figs. 11-57 and 11-59). The left artery arises from the arch of the aorta in the
superior mediastinum (see page 125). The common carotid artery runs upward through the neck
under cover of the anterior border of the sternocleidomastoid muscle, from the sternoclavicular
joint to the upper border of the thyroid cartilage. Here it divides into the external and internal
carotid arteries (Figs. 11-55 and 11-60).
Carotid Sinus
At its point of division, the terminal part of the common carotid artery or the beginning of the
internal carotid artery shows a localized dilatation, called the carotid sinus (Fig. 11-60). The tunica
media of the sinus is thinner than elsewhere, but the adventitia is relatively thick and contains
numerous nerve endings derived from the glossopharyngeal nerve. The carotid sinus serves as a
reflex pressoreceptor mechanism: A rise in blood pressure causes a slowing of the heart rate and
vasodilatation of the arterioles
Carotid Body
The carotid body is a small structure that lies posterior to the point of bifurcation of the common
carotid artery (Fig. 11-60). It is innervated by the glossopharyngeal nerve. The carotid body is a
chemoreceptor, being sensitive to excess carbon dioxide and reduced oxygen tension in the blood.
Such a stimulus reflexly produces a rise in blood pressure and heart rate and an increase in
respiratory movements.
The common carotid artery is embedded in a connective tissue sheath, called the carotid sheath,
throughout its course and is closely related to the internal jugular vein and vagus nerve
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Relations of the Common Carotid Artery
Anterolaterally: The skin, the fascia, the sternocleidomastoid,
the sternohyoid, the sternothyroid, and the superior belly
of the omohyoid (Fig. 11-55)
Posteriorly: The transverse processes of the lower four
cervical vertebrae, the prevertebral muscles, and the
sympathetic trunk (Fig. 11-57). In the lower part of the neck
are the vertebral vessels.
Medially: The larynx and pharynx and, below these, the
trachea and esophagus (Fig. 11-49). The lobe of the thyroid
gland also lies medially.
Laterally: The internal jugular vein and, posterolaterally, the
vagus nerve (Fig. 11-49)
Branches of the Common Carotid Artery
Apart from the two terminal branches, the common carotid artery gives off
no branches
Branches of the Internal Carotid Artery
There are no branches in the neck. Many important branches, however, are
given off in the skull
Branches of the External Carotid Artery
Superior thyroid artery
Ascending pharyngeal artery
Lingual artery
Facial artery
Occipital artery
Posterior auricular artery
Superficial temporal artery
Maxillary artery
Subclavian Arteries
Right Subclavian Artery
The right subclavian artery arises from the brachiocephalic
artery, behind the right sternoclavicular joint (Figs. 11-57
and 11-59). It arches upward and laterally over the pleura
and between the scalenus anterior and medius muscles.
At the outer border of the first rib, it becomes the axillary
artery.
Left Subclavian Artery
The left subclavian artery arises from the arch of the aorta
in the thorax. It ascends to the root of the neck and then
arches laterally in a manner similar to that of the right
subclavian artery .
The scalenus anterior muscle passes anterior to the artery
on each side and divides it into three parts
First Part of the Subclavian Artery
The first part of the subclavian artery extends from the origin of the subclavian artery to the medial border
of the scalenus anterior muscle (Fig. 11-57). This part gives off the vertebral artery, the thyrocervical
trunk, and the internal thoracic artery.
Branches
The vertebral artery ascends in the neck through the foramina in the transverse processes of the upper six
cervical vertebrae (Fig. 11-57). It passes medially above the posterior arch of the atlas and then
ascends through the foramen magnum into the skull. On reaching the anterior surface of the medulla
oblongata of the brain at the level of the lower border of the pons, it joins the vessel of the opposite
side to form the basilar artery.
The basilar artery (Fig. 11-15) ascends in a groove on the anterior surface of the pons. It gives off branches
to the pons, the cerebellum, and the internal ear. It finally divides into the two posterior cerebral
arteries.
On each side, the posterior cerebral artery (Fig. 11-15) curves laterally and backward around the midbrain.
Cortical branches supply the inferolateral surfaces of the temporal lobe and the visual cortex on the
lateral and the medial surfaces of the occipital lobe.
Branches in the neck: Spinal and muscular arteries
Branches in the skull: Meningeal, anterior and posterior spinal, posterior inferior cerebellar, medullary
arteries
The thyrocervical trunk is a short trunk that gives off three terminal branches (Fig. 11-57).
The inferior thyroid artery ascends to the posterior surface of the thyroid gland, where it is closely related
to the recurrent laryngeal nerve. It supplies the thyroid and the inferior parathyroid glands.
The superficial cervical artery is a small branch that crosses the brachial plexus (Fig. 11-57).
The suprascapular artery runs laterally over the brachial plexus and follows the suprascapular nerve onto
the back of the scapula (Fig. 11-57).
The internal thoracic artery descends into the thorax behind the first costal cartilage and in front of the
pleura (Fig. 11-57). It descends vertically one fingerbreadth lateral to the sternum; in the sixth
intercostal space, it divides into the superior epigastric and the musculophrenic arteries.
Second Part of the Subclavian Artery
The second part of the subclavian artery lies behind the scalenus
anterior muscle (Fig. 11-57).
Branches
The costocervical trunk runs backward over the dome of the pleura and
divides into the superior intercostal artery, which supplies the first
and the second intercostal spaces, and the deep cervical artery,
which supplies the deep muscles of the neck.
Third Part of the Subclavian Artery
The third part of the subclavian artery extends from the lateral border
of the scalenus anterior muscle (Fig. 11-57) across the posterior
triangle of the neck to the lateral border of the first rib, where it
becomes the axillary artery. Here, in the root of the neck, it is closely
related to the nerves of the brachial plexus.
Branches
The third part of the subclavian artery usually has no branches.
Occasionally, however, the superficial cervical arteries, the
suprascapular arteries, or both arise from this part.
Veins of the Face and the Neck
Facial Vein
The facial vein is formed at the medial angle of the eye by the union of the supraorbital
and supratrochlear veins (Fig. 11-39). It is connected through the ophthalmic veins
with the cavernous sinus. The facial vein descends down the face with the facial
artery and passes around the lateral side of the mouth. It then crosses the
mandible, is joined by the anterior division of the retromandibular vein, and drains
into the internal jugular vein.
Superficial Temporal Vein
The superficial temporal vein is formed on the side of the scalp (Fig. 11-39). It follows
the superficial temporal artery and the auriculotemporal nerve and then enters the
parotid salivary gland, where it joins the maxillary vein to form the retromandibular
vein.
Maxillary Vein
The maxillary vein is formed in the infratemporal fossa from the pterygoid venous
plexus (Fig. 11-39). The maxillary vein joins the superficial
temporal vein to form the retromandibular vein
Retromandibular Vein
The retromandibular vein is formed by the union of the superficial temporal and the
maxillary veins (Fig. 11-39). On leaving the parotid salivary gland, it divides into an
anterior branch, which joins the facial vein, and a posterior branch, which joins the
posterior auricular vein to form the external jugular vein.
External Jugular Vein
The external jugular vein is formed behind the angle of the jaw by the union of the posterior auricular vein with the
posterior division of the retromandibular vein (Fig. 11-39). It descends across the sternocleidomastoid muscle
and beneath the platysma muscle, and it drains into the subclavian vein behind the middle of the clavicle.
Tributaries
Posterior external jugular vein from the back of the scalp
Transverse cervical vein from the skin and the fascia over the posterior triangle
Suprascapular vein from the back of the scapula
Anterior jugular vein
Anterior Jugular Vein
The anterior jugular vein descends in the front of the neck close to the midline (Fig. 11-39). Just above the sternum,
it is joined to the opposite vein by the jugular arch. The anterior jugular vein joins the external jugular vein
deep to the sternocleidomastoid muscle.
Internal Jugular Vein
The internal jugular vein is a large vein that receives blood from the brain, face, and neck (Fig. 11-39). It starts as a
continuation of the sigmoid sinus and leaves the skull through the jugular foramen. It then descends through
the neck in the carotid sheath lateral to the vagus nerve and the internal and common carotid arteries. It ends
by joining the subclavian vein behind the medial end of the clavicle to form the brachiocephalic vein.
Throughout its course, it is closely related to the deep cervical lymph nodes.
The vein has a dilatation at its upper end called the superior bulb and another near its termination called the
inferior bulb. Directly above the inferior bulb is a bicuspid valve
Tributaries of the Internal Jugular Vein
Inferior petrosal sinus
Facial vein (
Pharyngeal veins
Lingual vein
Superior thyroid vein (
Middle thyroid vein
Subclavian Vein
The subclavian vein is a continuation of the axillary vein
at the outer border of the first rib .It joins the internal
jugular vein to form the brachiocephalic vein, and it
receives the external jugular vein. In addition, it often
receives the thoracic duct on the left side and the right
lymphatic duct on the right.
Relations
Anteriorly: The clavicle
Posteriorly: The scalenus anterior muscle and the phrenic
nerve
Inferiorly: The upper surface of the first rib
Lymph Drainage of the Head and Neck
The lymph nodes of the head and neck (Fig. 11-40) are arranged as a regional collar
that extends from below the chin to the back of the head and as a deep vertical
terminal group that is embedded in the carotid sheath in the neck (Fig. 11-55).
Regional Nodes
The regional nodes are arranged as follows:
Occipital nodes: These are situated over the occipital bone on the back of the skull.
They receive lymph from the back of the scalp.
Retroauricular (mastoid) nodes: These lie behind the ear over the mastoid
process. They receive lymph from the scalp above the ear, the auricle, and the
external auditory meatus.
Parotid nodes: These are situated on or within the parotid salivary gland. They
receive lymph from the scalp above the parotid gland, the eyelids, the parotid
gland, the auricle, and the external auditory meatus.
Buccal (facial) nodes: One or two nodes lie in the cheek over the buccinator
muscle. They drain lymph that ultimately passes into the submandibular nodes.
Submandibular nodes: These lie superficial to the submandibular salivary gland
just below the lower margin of the jaw. They receive lymph from the front of
the scalp; the nose; the cheek; the upper lip and the lower lip (except the
central part); the frontal, maxillary, and ethmoid sinuses; the upper and lower
teeth (except the lower incisors); the anterior two thirds of the tongue (except
the tip); the floor of the mouth and vestibule; and the gums
Submental nodes: These lie in the submental triangle just below
the chin
. They drain lymph from the tip of the tongue, the floor of the
anterior part of the mouth, the incisor teeth, the center part of
the lower lip, and the skin over the chin.
Anterior cervical nodes: These lie along the course of the anterior
jugular veins in the front of the neck. They receive lymph from
the skin and superficial tissues of the front of the neck.
Superficial cervical nodes: These lie along the course of the
external jugular vein on the side of the neck. They drain lymph
from the skin over the angle of the jaw, the skin over the lower
part of the parotid gland, and the lobe of the ear.
Retropharyngeal nodes: These lie behind the pharynx and in front
of the vertebral column. They receive lymph from the nasal
pharynx, the auditory tube, and the vertebral column.
Laryngeal nodes: These lie in front of the larynx. They receive
lymph from the larynx.
Tracheal (paratracheal) nodes: These lie alongside the trachea.
They receive lymph from neighboring structures, including the
thyroid gland.
Deep Cervical Nodes
The deep cervical nodes form a vertical chain along the
course of the internal jugular vein within the carotid
sheath .
They receive lymph from all the groups of regional nodes.
The jugulodigastric node, which is located below and
behind the angle of the jaw, is mainly concerned with
drainage of the tonsil and the tongue. The juguloomohyoid node, which is situated close to the
omohyoid muscle, is mainly associated with drainage of
the tongue.
The efferent lymph vessels from the deep cervical lymph
nodes join to form the jugular trunk, which drains into
the thoracic duct or the right lymphatic duct
Main Nerves of the Neck
Cervical Plexus
The cervical plexus is formed by the anterior rami of the first four cervical nerves. The rami are joined by
connecting branches, which form loops that lie in front of the origins of the levator scapulae and the
scalenus medius muscles (Fig. 11-57). The plexus is covered in front by the prevertebral layer of deep
cervical fascia and is related to the internal jugular vein within the carotid sheath. The cervical plexus
supplies the skin and the muscles of the head, the neck, and the shoulders.
Branches
Cutaneous branches
The lesser occipital nerve (C2), which supplies the back of the scalp and the auricle
The greater auricular nerve (C2 and3), which supplies the skin over the angle of the mandible
The transverse cervical nerve (C2 and 3), which supplies the skin over the front of the neck
The supraclavicular nerves (C3 and 4). The medial, and intermediate, and lateral branches supply the skin
over the shoulder region. These nerves are important clinically, because pain may be referred along
them from the phrenic nerve (gallbladder disease).
Muscular branches to the neck muscles. Prevertebral muscles, sternocleidomastoid (proprioceptive, C2 and
3), levator scapulae (C3 and 4), and trapezius (proprioceptive, C3 and 4). A branch from C1 joins the
hypoglossal nerve. Some of these C1 fibers later leave the hypoglossal as the descending branch, which
unites with the descending cervical nerve (C2 and 3), to form the ansa cervicalis (Fig. 11-60). The first,
second, and third cervical nerve fibers within the ansa cervicalis supply the omohyoid, sternohyoid, and
sternothyroid muscles. Other C1 fibers within the hypoglossal nerve leave it as the nerve to the
thyrohyoid and geniohyoid.
Muscular branch to the diaphragm. Phrenic nerve
Phrenic Nerve
The phrenic nerve arises in the neck from the third,
fourth, and fifth cervical nerves of the cervical plexus.
It runs vertically downward across the front of the
scalenus anterior muscle (Fig. 11-57) and enters the
thorax by passing in front of the subclavian artery. Its
further course in the thorax is described on page 127.
The phrenic nerve is the only motor nerve supply to the
diaphragm. It also sends sensory branches to the
pericardium, the mediastinal parietal pleura, and the
pleura and peritoneum covering the upper and lower
surfaces of the central part of the diaphragm
Brachial Plexus
The brachial plexus is formed in the posterior triangle of the neck by the
union of the anterior rami of the fifth, sixth, seventh, and eighth cervical
and the first thoracic spinal nerves (Fig. 11-71). This plexus is divided into
roots, trunks, divisions, and cords. The roots of C5 and 6 unite to form
the upper trunk, the root of C7 continues as the middle trunk, and the
roots of C8 and T1 unite to form the lower trunk. Each trunk then divides
into anterior and posterior divisions. The anterior divisions of the upper
and middle trunks unite to form the lateral cord, the anterior division of
the lower trunk continues as the medial cord, and the posterior divisions
of all three trunks join to form the posterior cord.
The roots of the brachial plexus enter the base of the neck between the
scalenus anterior and the scalenus medius muscles (Fig. 11-57). The
trunks and divisions cross the posterior triangle of the neck, and the
cords become arranged around the axillary artery in the axilla (see Fig. 920). Here, the brachial plexus and the axillary artery and vein are
enclosed in the axillary sheath