1. No category

Anatomy of neck + innervation of
structures. Anatomy (gross and
histological) and physiology of the
lymphoid system, and of the head
and neck –light, clinically relevant
summary - DAN
From now I will pay more attention when
we formulate FQs because this one sucked
Contents
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Neck Fascia
Danger Triangle
Larynx and Thyroid gland
Cervical lymphatic drainage
Fascia of the Neck
• Structures in the neck are surrounded by a
superficial fascia (subcutaneous tissue)
• They are compartmentalised by layers of deep
cervical fascia.
The Fascial layers
• Superficial cervical fascia
– Thin layer of CT that lies between the dermis of
the skin and the investing layer of the deep
cervical fascia
– Cutaneous nerves, blood and lymph vessels,
superficial lymph nodes, continous anterolaterally
with the platysma
• Deep cervical fascia
– Investing layer, pretracheal layer, Prevertebral
layer, Alar fascia and carotid sheath
Neck fascia
SUPERFICIAL CERVICAL FASCIA
Subcutaneous tissue
Investing layer
Pretracheal layer
Carotid sheath
Pre vertebral lyaer
DEEP CERVICAL FASCIA
Retropharyngeal space
Investing layer
• Surrounds: Sternocleoidomastoids, Trapezius,
submandibular gland, parotid gland
• Superior attachments: Superior nuchal line,
mastoid processes, zygomatic arches, inferior
border of mandible, hyoid, spinous processes
of cervical vertibrae
Pretracheal layer
• Includes
– Visceral part (thyroid gland, trachea, oesophagus)
– Muscular part (infrahyoid muscles)
• Continuous with
– Carotid sheaths laterally
– Buccopharyngeal fascia posterosuperiorly
– Pericardium inferiorly
Carotid Sheath
• Extends from cranial base – root of neck
• Continuous
– Anteriorly: investing and pretracheal layer
– Posteriorly: Prevertebral layer
• Important structures hidden within:
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Common + internal carotid arteries
IJV
CN X
Deep cervical nodes
Carotid sinus nerve
Sympathetic nerve fibres
Pre Vertebral layer
• Fixed to the cranial base superiorly, inferiorly
fuses with the anterior longitudinal ligament
• Forms a tubular sheath for the vertebral
column and muscles surrounding it.
Retropharyngeal space
• The largest interfascial space in the neck.
• Potential space that consists of loose
connective tissue between the prevertebral
layer and the pretracheal layer.
• The Alar fascia crosses the retropharyngeal
space
• Allows the movement of the pharynx,
oesophagus, larynx and trachea
• Major pathway for spread of infection
Neck fascia
SUPERFICIAL CERVICAL FASCIA
Subcutaneous tissue
Investing layer
Pretracheal layer
Carotid sheath
Pre vertebral lyaer
DEEP CERVICAL FASCIA
Retropharyngeal space
Importance of Fascia + its layers
• Spread of infection is limited by facsial
boundaries
• Example
– An Pus abscess posterior to the prevetebral layer
may extend laterally in the neck and form a
swelling posterior to the SCM. The pus may
perforate the prevertebral layer and enter the
retropharyngeal space, producing a bulge in the
pharynx.
• Dsyphagia, dysarthria
Danger triangle of the FACE
• There is a communication between the facial
vein and the cavernous sinus via the via
the ophthalmic veins.
• Bacterial infections can be caused by pus
entering the brain's blood supply if pimples in
the danger triangle are picked by dirty
fingernails.
How???
Area of drainage of the facial vein
Larnyx
Larynx
• Innervation
• Motor: recurrent laryngeal nerves
• S: superior laryngeal nerves
• Blood supply
• Superior half: superior laryngeal a. (branch of the s. Thyroid
a.)
• Inferior half: inferoir laryngeal artery (branch of the i.
Thyroid artery)
• Lymph drainage:
• Superior + inferior deep cervical nodes  jugular trunk 
thoracic duct (L)/right thoracic duct (R)
PIE CHART
Larynx size
Angus
Average
Thyroid Gland
• Innervation
• Parasympathetic fibers come from the vagus nerves
• Sympathetic fibers are distributed from the superior,
middle, and inferior ganglia of the sympathetic trunk.
– Blood supply
• Superior half: superior thyroid artery
• Inferior half: inferior Thyroid artery
• Lymph drainage: periglandular nodes 
prelaryngeal  pretracheal  paratracheal 
mediastinal lymph nodes.
Thyroid gland
Epithelium (principle cells)
Colloid filled follicle
parafollicular cells
Anatomy of the Lymphoid system
• Lymph nodes
• Lymph Vessels
– Main lymphatic vessels in the body
• Right lymphatic duct
• Thoracic duct
• Cisterna Chyli
Lymphatic system/ Immune System
Lymph Node
Lymph node Histology
Important lymphatic sites
Waldeylers rings
• Waldeyer's-Pirogov tonsillar ring describes the
lymphatic tissue in the pharynx and to the
posterior oral cavity.
• It contains
– Pharyngeal tonsil (also known as 'adenoids' when
infected)
– Tubal tonsil (where Eustachian tube opens in the
nasopharynx)
– Palatine tonsils
– Lingual tonsils
Cervical lymph node drainage
Main lymph node groups in the neck
– Submental/ Submandibular
– Parotid
– Retropharyngeal
– Anterior cervical
– Deep lateral cervical
Submental/Submandibular
• 1. Submental nodes
– drainage from: adjacent skin, lips,
floor of the mouth
– drain to: the submandibular nodal
group
• 2. Submandibular nodes
– drainage from : anterior face, flow
of the mouth, anterior oral cavity,
and submental nodal group.
– drain to :the high internal jugular
chain (7)
Parotid
• 8. Parotid gland nodes
• Intra or extra glandular
nodes.
• drainage from: external
artery canal, eustachian
tube, adjacent skin,
buccal mucosa.
• drain to: high internal
jugular chain (7)
Retropharyngeal
• Two compartments: Medial and lateral
retropharyngeal.
• Medial retropharyngeal
– drainage from: nasal pharynx and oral
pharynx
– drain to: high internal jugular chain.
• Lateral retropharyngeal: same as medial
• Clinical sign: Early sign of nasal
pharyngeal cancer may be presence of
abnormal lateral retropharyngeal node in
the patient over forty.
Deep Lateral cervical
• Consists of
– Internal Jugular chain (7)
• drainage from: from parotid,
retropharyngeal, and
submandibular/submental groups.
• drain to: the subclavian vein and/or
internal jugular vein and/or into the
right lymphatic duct and thoracic
duct.
– Posterior triangle
• drainage from: occipital/mastoid,
lateral neck, scalp, nasal
pharyngeal sources.
• drain to:
– Supraclavicular: Same as Post.
Triangle
Anterior cervical
• Anterior jugular: superficial. Follows the course of
the external jugular vein. Receives drainage from
skin and muscles of the anterior neck. Drains to
the thoracic duct.
• Paraesophageal group: Tracheal esophageal
groove nodes and delphian node. Abnormal
delphian node is often an indicator subglottic
laryngeal cancer extension.
• This group receives drainages from hypopharynx,
larynx, thyroid, and esophagus. Drainage is then
to the thoracic duct.
Physiology of the lymphoid system
• Re-uptake of excess fluid in interstitial tissue
at capillary beds
• Antigen presentation to naive lymphocytes
• Activation of naive lymphocytes