Fascia and Viscera of the Neck Flashcards
What is fascia?
- Type of connective tissue
- Dense regular CT
- Formed primarily of collagen
- organized into sheets or bands
Types of fascia
Superficial: subcutis layer of the skin, loose fascia and fat
Deep (investing): surrounds muscles, bones and neurovascalature
Visceral: envelops and suspends organs
Potential spaces
Fascial layers form potential spaces between layers that are normally pressed together
abnormally, these spaces may fill with gas/fluid to create actual spaces
e.g. pleural space, fascial spaces, subdural space
Fascia Layers of the Neck
superficial cervical fascia
deep cervical fascia
Platysma muscle
derived from superficial fascia
cells from the embryo somite (myotome, hypomere) invade the superficial fascia to form this muscle
Deep Cervical Fascia Layers
Outer (investing) layer
middle layer
visceral layer
inner layer (preventebral)
carotid sheaths
outer (investing) layer
surrounds SCM and trapezius muscles
surrounds parotid and submandibular glands as parotidomasseteric fascia
middle layer
Surrounds strap (infrahyoid) mm.
sternothyroid m.
sternohyroid m.
thyrohyoid m.
omohyoid m.
visceral layer
Surrounds pharynx, larynx, trachea and esophagus
pretracheal fascia (anterior)
buccopharyngeal fascia (posterior)
inner layer
surrounds vertebral column and paraspinous mm.
AKA prevertebral fascia
Carotid Sheaths
- Formed by components of middle, visceral and inner layers
- surround carotid a., interal jugular v., vagus n. (CNX), deep cervical lymph nodes
- the sympathetic chain and ansa cervicalis are embedded in the fascia but not inside the sheath
- joined by the alar fascia, which crosses the midline
Retropharyngeal Space
Between buccopharyngeal and alar fasciae
divided down the middle by a septum (unilateral infections)
posterior to pharynx
extends into the superior mediastinum
Alar Space - “Danger Space”
Between alar and prevertabral fasciae
extends into thorax, ends at diaphragm
True or False
Only the Superficial cervical fascial envelops the entire head as the superficial crancial fascia
TRUE
Deep Fascia of Head
Outer layer becomes
Inner layer becomes
Outer layer becomes parotidomasseteric and temporal fascial, also covers pterygoid mm.
visceral layer: buccopharngeal fascia covers the buccinator m.
other layers not repesents in head
Buccal Space
Between buccopharyngeal and superfical cranial fasciae
Vestibular Space
Between oral mucosa and buccinator muscle
Dental infections spread to
Buccal and vestibular spaces and into the retropharyngeal space
Infections of tonsilar ring can spread…
into retropharnygeal space
advanced retropharyngeal infections spread
into the alar (danger) space
alar / danger space infections spread
spread to thorax and heart
Carotid sheath contents
common carotid artery
internal jugular vein
vagus nerve (CNX)
deep cerival lymph nodes
sympathetic chains and ansa cervicalis are embedded in carotid sheath fascia but are not inside the sheath
Common Carotid Artery: splits into
internal and external carotid arteries at the level:
C4 vertabrae and upper thyroid cartilage
Carotid Sinus (Common Carotid Artery)
baroreceptors (blood pressure)
carotid sinuses clogged? stick a bar in it
Carotid Body (Common Carotid Artery)
Chemoreceptors (O2 CO2)
chemo hurts carotid body
Glossopharyngeal Nerve (CN IX) (Common Carotid Artery)
GVA innervation
Syncope
Fainting
Caused by decreased blood flow to brain (due to low blood pressure or low blood O2)
can be caused by compression of the carotid body
other types of syncope: orthostatic, cardiac arythmias
External Carotid Artery
- To neck, face and meninges
- Superior thyroid a.
- ascending pharyngeal a.
- lingual a.
- facial a.
- occipital a.
- posterior auricular a.
- maxillary a.
- superficial temporal a.
Carotid Endarterectomy
Surgical correction of stenosis (narrowing) and/or removal of plaques from carotid arteries
blockage of the carotids is a high risk factor for strokes
rupture of the plaques can travel up the internal carotid artery to the brain and become lodged in the cerebral arteries
layers of cervical viscera
endocrine layer: thyroid and parathyroid glands
respiratory layer: larynx and trachea
alimentary layer: pharynx and esophagus
thyroid gland
largest endocrine gland
2 lobes connected by an isthmus
produces thyroid hormone (metabolism) and calcitonin (calcium metabolism)
develops at base of tongue then descends into neck
Parathyroid gland
superior and inferior pairs
produce PTH - phosphorous and calcium metabolism
targets the skeleton, kidney and intestines
Common complication of thyroid biopsies
is RLN palsy, a unilateral and often temporary
(due to swelling) weakness of the vocal cords
Larynx
Organ of voice production
SVE innervation from the vagus n. (CNX)
Laryngeal skeleton made of hyaline cartilage
Trachea
Upper respiratory tract
supported by tracheal rings
Pharynx
- muscular tube that connects nasal and oral cavities with the esophagus and larynx
- innervated by pharyngeal plexus
- GVA - CNIX
- SVE - CNX
Esophagus
Muscular tube that connects pharynx to stomach
cervical portion (upper 1/3) is skeletal muscle (SVE CNX)
Thoracic portion (lower 2/3) is smooth muscle (GVE CNX)
Salivary Glands
- Exocrine glands
- produce salivia (digestive enzyme)
- amylase - breaks down complex starches/carbs
- beginning of chemical digestion
- heavily vascularized, surrounded by lymph nodes
