Anatomy of the Neck

1
Anatomy of the Neck
2
Anterior triangle

• Midline of the neck
• Sternocleidomastoid muscle
• Lower border of the mandible

3
Subunits of ant. triangle

• Submandibular triangle
• Submental triangle
• Carotid triangle
• Muscular triangle

4
Submandibular triangle

• Anterior posterior bellies of digastric muscle
• Lower border of the mandible

5
Submental triangle

• Anterior bellies of the digastric muscle
• Hyoid bone

6
Posterior triangle

• Anterior border of the trapezius m.
• SCM
• Middle third of the clavicle

7
Subunits of post. Triangle

• Subclavian triangle
• Occipital triangle

8
Fascial layer of the neck

• The cervical fascia represents a condensation
  of connective tissue that extends between
  anatomic structures

9
Superficial Fascia

• Lies just below the dermis
• Deep portions of this layer encase the platysma
  muscle as well as the voluntary muscles of the
  face scalp

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Deep cervical fascia

• Superficial layer
• Middle layer
• Deep layer

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Superficial layer of deep cervical fascia

• Begins from the vertebral spinous processes and
  splits to enclose the trapezious
• Again it splits to invest SCM as well as strap
  muscle
• Superior attachment occipital protuberance ,
  superior nuchal line zigomatic arch

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• Between parotid submandibular glands the two
  layer rejoin to form the stylomandibular ligament
  
• Inferiorly the fascia split and attach to the
  anterior and posterior surface of the sternum
  Suprasternal space of Burns

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Middel layer of the deep cervical fascia

• It encloses the thyroid gland , trachea ,
  pharyngeal constrictor muscle esophagus
• It extends from the hyoid bone down to the
  sternal attachments and is continuous with
  fibrous pericardium

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Deep layer of the deep cervical Fascia

• Anterior to the vertebral bodies
• Tips of transverse process
• Vertebral spines posteriorly
• From the skull base until the coccyx

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• Prevertebral layer
• Alar layer ( until first thoracic vertebra )

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Danger space

• A potential space is created between the alar and
  prevertebral fascias because it communicates
  directly with the mediastinum

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Prevertebral space

• Between the prevertebral fascia and vertebral
  body

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Retropharyngeal space

• Between alar and the visceral fascia

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Tissue space of the neck

• Between cervical fascia exist potential spaces

20

• Because superficial and deep layers of the
  deep cervical fascia fuse at the hyoid bone
  infection in the spaces above the hyoid does not
  spread directly to spaces below the hyoid

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• Communication along the entire length of the
  neck occurs posteriorly along the retropharyngeal
  and prevertebral spaces .

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Submandibular space

• Between outer space of of mylohyoid muscle and
  superficialstructure within submandibular
  triangle
• Along the posterior free edge of the mylohyoid
  muscle it continuous with the sublingual space
• It also communicate with submental and
  contralateral submandibular space

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Intrapharyngeal space

• Inner surface of the superior constrictor muscle
  and the pharyngeal mucosa
• It also known as peritonsillar space

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Parapharyngeal space

• Medial superior constrictor m.
• Lateral pterygoid muscles and fascia of the
  parotid gland
• Inferior Fascial attachment to the hyoid

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• Posteromedially this space communicates with the
  retropharyngeal space providing a route to spread
  infection

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Retropharyngeal space

• Entire length of the neck
• Between visceral fascia and alar fascia
• From the skull base down to the T1

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Danger space

• Between alar fascia and prevertebral fascia
• Retropharyngeal space? danger space ?mediastinum

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Prevertebral space

• Between prevertebral fascial and vertebral column
  
• From the skull base to the lower thoracic area

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Artery of the neck
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Common carotid artery

• Right side from brachiocephalic artery
• Left side from aortic arch
• It crosses by omohyoid muscle , , superior
  middle thyroid vein

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Internal carotid artery

• it crosses by hypoglossal nerve , occipital
  artery posterior belly of digastric muscle
• Near skull base it crosses by glossopharyngeal
  nerve ,stylohyoid , stylopharyngeous
  ,styloglossus muscle and styloid process

32
External carotid artery

• It crosses superficially to styloglossus and
  stylopharyngeous muscle
• Terminal branches passing behind the condylar
  process

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Superior thyroid artery

• At the level of greater horn hyoid bone
• Superior part of thyroid gland , larynx and SCM

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Ascending pharyngeal artery

• At the level of sup. Thyroid artery posteriorly
• Supply pharynx , palate , tonsil , middle ear and
  meninges

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Lingual artery

• Above the superior thyroid artery
• Runs anterior and superior
• Passes beneath the hyoglossus muscle to enter the
  tongue

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Facial artery

• On the anterior surface of carotid , deep to the
  digastric muscle
• Passes through the submandibular gland , crosses
  the inferior border of the mandible
• Branches in the neck ascending palatine artery
  , tonsillar artery , branches of the
  submandibular gland , submental artery

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Occipital artery

• From posterior surface of the external carotid
  artery the hypoglossal nerve hooks around it
• Supply suboccipital region of the scalp , SCM ,
  digastric and stylohyoid muscle

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Posterior auricular artery

• Posteriorly at the level of the upper border of
  digastric muscle
• Passes between the mastoid and ear
• Branches to the parotid gland , auricle and scalp

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Terminal branches

• Superficial temporal toward the scalp
• Maxillary artery infratemporal fossa ?
  pterygopalatine fissure ? pterygopalatine fossa

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Thyrocervical thrunk

• Arises from the first part of the subclavian
  artery just anterior to the scalenus anrerior
  muscle
• Transverse cervical branch ? SCM , trapezius
• Inferior thyroid artery deep to the carotid
  sheath
• Supply inferior portion of the thyroid , sup.
  inf. Parathyroid gland and a portion of larynx
  and trachea
• Inter the thyroid at the level of cricoid

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Vein of the neck
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Internal jugular vein

• Sigmoid sinus ? intrenal jugular vein ?
  subclavian vein
• Major tributaries inferior petrosal sinus
• Common facial vein
• lingual vein
• superior thyroid
  vein
• middle thyroid
  vein

43
External jugular vein

• Posterior auricular vein posterior branch
  retromandibular vein
• Deep to the platysma but superficial to the SCM
• Terminate in the subclavian vein
• At its midportion it joined by posterior external
  jugular vein

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Anterior jugular vein

• Confluence of the vein in the submandibular
  region
• Drain to the external jugular or subcalavian vein

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Nerve of the neck
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Glossopharyngeal nerve

• Sensory , motor , parasympathic component
• It has superior and inferior ganglion
• Anterior to the internal and deep to the external
  carotid artery
• Pass between superior and middle constrictor
  muscle
• Innervate tonsil , pharynx and tongue

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Tympanic nerve

• Arises from inferior ganglion
• Tympanic canaliculus ? middle ear (jacobson nerve
  )
• Sensory fiber to the middle ear , eustachian tube
  and mastoid cavity

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Lesser petrosal nerve

• Preganglionic parasympathetic fibers
• Tympanic plexus ? floor of middle cranial fossa ?
  foramen oval ? infratemporal fossa ? otic
  ganglion
• In the otic ganglion it synapsis with
  postganglionic fiber of parasympathic that supply
  the parotid gland

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Carotid branch

• Arises from IX nerve just below the skull base
• Unit with carotid branch of vagus nerve and
  carries sensory information back from the carotid
  body and carotid sinus

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Pharyngeal branch

• Reach to the pharyngeal plexus on the middle
  constrictor muscle
• Sensory innervation

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Stylopharyngeus branch

• Only motor branch of the IX nerve
• Supply stylopharyngeal muscle

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Tonsilar branch

• Form a plexus with the lesser palatine nerve
• Supply tonsil and soft palate

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Lingual branch

• Taste and general sensation to the posterior 1/3
  tongue

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Vagus nerve
55

• Superior and inferior ganglion at the jugular
  foramen
• Sensory , motor and parasympathetic fibers

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Superior ganglion branches

• Meningeal branch( posterior cranial fossa )
• Auricular branch (pinna, EAC, TM )

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Superior ganglion branch

• Pharyngeal branch ( pharynx and palate )
• Superior laryngeal nerve
• Right RLN in front the subvlavian a.
• Left RLN in front the aortic arch

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Accessory Nerve
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• Cranial component sensory
• Join the
  vagus nerve
• pharyngeal
  plexus
• Spinal component motor ( C2 C4 )
• lateral to IJV
• emerge 1 cm
  above Erb point

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Hypoglossal nerve

• Occipital bone ? under posterior belly digastric
  ? looping around occipital a.?
• across carotid arteries ? deep to the
  submandibular gland ? on the surface of
  hyoglossus muscle
• Innervation interinsic muscle of tongue ,
  styloglossus , hyoglossus , genioglossus

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Ansa cervicalis

• Motor innervation to the strap muscle
• Upper branch hypoglossus nerve
• Lower branch C2 , C3 from the cervical plexus

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Cervical sympathetic trunk

• Thoracic spinal cord ? sympathetic cervical
  ganglia ?
• Superior cervical ganglia ( at the level of the
  C2 C3 behind the carotid sheath
• internal carotid nerve passes into carotid
  canal ? internal carotid plexus

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Cervical sympathic (cont )

• Middle cervical ganglia
• At the level of
  C6
• Inferior cervical ganglia
• in the root of
  the neck

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Cervical plexus

• From C1 C6
• Motor sensory nerve
• Phrenic nerve (motor br C3,C4,C5 )
• Sensory br lesser occipital nerve
• greater auricular nerve
• Anterior cutaneous nerve
• supraclavicular nerve

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Lymphatics of the neck

• Superficial group submental
• submandibular
• superficial
  cervical
• anterior
  cervical
• Deep group pretracheal ,
• paratracheal
• perithyroid
• retropharyngeal

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The node of Rouviere refers to the highest
retropharyngeal lymph node which is adjacent to
the jugular foramen
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Compartment of the neck
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Level I

• Posterior belly of the digastric muscle
• Body of the mandible
• Hyoid bone

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Submandibular nodes

• Preglandular
• Postglandular
• Prevascular
• Postvascular
• Intracapsular

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Drainage

• Upper lower lip , Cheek skin , nasal skin
  mucosa , medial canthus , anterior alveolus ,
  anterior tonsillar pillar soft palate , 2/3
  anterior of the tongue , submandibular salivary
  gland
• Drain into upper internal jugular nodes

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Submental nodes

• 2-8 nodes
• Between anterior belly of digastric muscle
• Mylohyoid platysma
• Drain mentum , midportion of the lower lip ,
  anterior alveous , anterior 1/3 of the tongue
• Second drainage to ipsilat. contralat.
  preglandular or prevascular submandibular nodes
  or IJV

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Level II

• Base of the skull ? carotid bifurcation or hyoid
  bone
• Posterior border of SCM ? lateral border of
  sternohyoid muscle

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Level III

• Carotid bifurcation to the omohyoid muscle or
  cricothyroid notch

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Level IV

• Along the inferior 1/3 of the IVJ from the
  omohyoid to the clavicle

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Level V

• From the anterior border of the trapezius m.
  to the posterior border of SCM and the clavicle
  inferiorly

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Level VI

• Surrounded midline visceral structure
• From the hyoid bone to the sternal notch
• The lateral border is the carotid sheath
• Consists of paratracheal node , perithyroid nodes
  , precricoid ( Delphian ) nodes and nodes along
  the RLN

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Level VII

• The upper mediastinal lymph node and inferior to
  the suprasternal notch

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Anterior nodal group

• Anterior jugular chain
• Juxtavisceral chain prelaryngeal
• prethyroid
• pretracheal
• paratracheal

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• Prelaryngeal supraglottis
• Prethyriod infraglottic , thyroid isthmus ,
  anteromedial thyroid lobe
• Pretracheal node from thyroid isthmus to the
  innominate vein ,2-12 node ,thyroid gland and
  trachea
• Paratracheal lateral aspect of thyroid
  parathyroid gland , postcricoid , trachea,
  esophagus

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Lateral group

• Superficial chain
• related to EJV
  
• drain to transverse
  cervical

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Deep group

• Spinal accessory chain
• Transverse cervical chain
• Internal jugular chain

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• Spinal accessory chain up to 20 nodes
• Transverse cervical chain 12 nodes
• Internal jugular chain 30 nodes
• on left side thoracic duct
• on right side right lymphatic duct
  

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Sublingual nodes

• Along collecting trunk of the tongue sublingual
  gland
• Drain anterior floor of the mouth ventral
  surface of the tongue
• Connect to the submandibular group or upper IJ
  chain

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Parotid Nodes

• Extraglandular group preauricular
  infraauricular nodes
• Drain lateral and frontal aspects of the scalp,
  anterior auricle , external auditory canal , skin
  of the lateral face , buccal mucosa
• Intraglandular nodes drain the same side

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Retropharyngeal node

• Between pharyngeal wall and prevertebral fascia
• Lateral group 1-3 nodes at the level of C1
• Medial group to the level of the cricoid
• Drain nasal cavity,sphenoid sinus, ethmoid
  sinus,hard soft palate, nasopharynx posterior
  pharyngeal wall

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The retropharyngeal space can be accessed by
rotating the pharynx medially and opening the
infected tissue between the pharynx and cervical
spine
87
Occipital nodes

• Superficial group 2-5 nodes
• Between SCM trapezius m. at apex of posterior
  triangle , superficial to the splenius m. deep
  to investing fascia
• Drain occipital scalp , posterior cervical skin ?
  deep group ? upper spinal accessory

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Postauricular nodes

• 1-4 nodes over fibrous insertion of SCM on the
  mastoid tip
• Drain posterior parietal scalp , skin of mastoid
  and postauricular area ? infraauricular parotid
  LN

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Cont.

• Deep group 1-3 nodes deep to the splenius m.
  along the course of the occipital artery
• Drain the deep musculature of the neck in
  occipital region? INJ spinal accessory nodes

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Thoracic duct

• Passes up through mediastinum ? left root of the
  neck ? posterior to the carotid sheath medial
  to the anterior scalene m.
• It empties through multiple branches into the
  lowest portion of the IJV , the subclavian vein
  or both
• Main duct may extend as high as 5 cm above the
  clavicle