Lecture 1 Flashcards
Four layers of fascia deep in the neck.
investing, pretracheal, carotid, prevertebral
Investing Fascia
seen when reflecting platysma and formed by anterior triangle of the neck, borders are the bottom of mandible, mastoid process, and external occipital protuberance
Pretracheal Fascia
continuous with pericarditis, thin and runs anteriorly only, muscular-encloses all infrahyoid muscles, visceral-encloses the thyroid, trachea, esophagus and ends in the pharynx
Carotid Fascia
most organs in this area are associated with this layer of fascia, tubular sheath that extends from the base of the skull to the base of the neck communicating freely with the mediastinum
Prevertebral Fascia
anterior to the ALL (blends with it), attached to the cervical and thoracic vertebrae, allows the muscles and viscera of the neck to have the displacement when palpating is a tubular sheath for the vertebral column and associated muscles
Which fascia is continuous with the pericardium and thus can lead to pericarditis with infection?
pretracheal fascia
Nerves and vessels going through the investing fascia.
superficial blood vessels associated with the external jugular, anterior communicating branch of superficial external jugular, 3-4 branches of cervical plexus (come from spinal cord): lesser occipital nerve (LO), supraclavicular (SC), greater auricular nerve (GA), transverse cervical nerve (TC)
Pretracheal fascia characteristics.
radiates in a longitudinal direction (longer than investing fascia), spans from base of cranium to base of superior mediastinum into boundaries of the plura, is tubular and lymphatics are located inside, lymphatics are main mechanism of metastasis
Two parts of the pretracheal fascia.
muscular - infrahyoids (depresses hyoid bone); visceral - encloses the thyroid, trachea, esophagus and ends in the pharynx
Pretracheal fascia borders.
base of skull to T2-T3
Which nerves pierce the prevertebral fascia?
lesser occipital, great auricular, transverse cervical, supraclavicular, inferior root of ansa cervicalis
What structures lie on the prevertebral fascia?
sympathetic chain, lymph nodes, spinal root of accessory nerve (phrenic nerve will be deep to this fascia)
What structures lie deep to the prevertebral fascia?
cervical plexus, trunks of brachial plexus, 3rd part of subclavian artery, phrenic nerve
Boundaries of prevertebral fascia.
superior - skull base; inferior - blends onto the endothoracic fascia; peripheral - fuses with the ALL; lateral - it extends as the axillary sheath; physically attaches to the vertebrae by the anterior longitudinal ligament to prevent overextension of the neck
Contents of the carotid sheath.
common and internal carotids aa’s, carotid sinus nn’s, internal jugular vein, CN X, some deep cervical lymph nodes, sympathetic nerve fibers
In the carotid sheath, fascia is thicker where it is connected to the artery. Why?
for protection and to reduce friction, can contain calcium and other minerals as well, muscular layer is larger where arteries are present (calcification of the fascia = sclerosis)
Parotid Sheath
at level of C1, holds the parotid gland for salivation, penetrated by Facial Nerve (CN VII), also innervated by branches of the Trigeminal Nerve (CN V)
What level of the spine is the hyoid bone located?
C3
What level of the spine is the thyroid cartilage located?
C4 and C5 (laryngeal prominence is the Adam’s apple)
What level of the spine is the cricoid cartilage located?
C6
Emergency site for tracheostomy vs. preferred site.
emergency - cricothyroid membrane; preferred - tracheal cartilages 2-4 (below cricoid cartilage and isthmus of the thyroid gland)
What is the risk associated with a high tracheostomy?
dangerous because chances to penetrate/cut the recurring laryngeal nerve are higher at that level
Anterior triangle
bordered by the anterior border of the SCM, midline of the neck, and the mandible; within the anterior triangle we find muscular, carotid, submental, and submandibular triangles
Muscular triangle
formed by sternothyroid, sternohyoid, thyroid and parathyroid glands
Carotid triangle
formed by the superior belly of the omohyoid, SCM, and posterior belly of the digastric
Submental triangle
formed by the anterior belly of the digastric, hyoid, and midline (smallest)
Submandibular triangle
formed by the mandible, posterior belly of the digastric, and anterior belly of the digastric (includes the submandibular gland)
Subclavian triangle
formed by inferior belly of the omohyoid, clavicle, and SCM (you can put your soap in there)
Occipital triangle
formed by inferior belly of the omohyoid, trapezius, and SCM
Medial branch (1) of external carotid artery.
ascending pharyngeal artery
Posterior branches (2) of external carotid artery.
occipital and posterior auricular arteries
Anterior branches (3) of external carotid artery.
superior thyroid, lingual, and facial arteries (from inferior to superior)
Facial artery pathway.
travels over angle of mandible and penetrates underneath the buccinator and found near the naris of the nostril (called angular artery), continually changing its name until it blends with the ophthalmic artery in the ocular compartment
Posterior triangle
subclavian and occipital triangles
Carotid body general characteristics.
epitheloid tissue covered by mesothelial tissue (not connective), used to sense chemical changes in pH of blood (Cl, O, H are too low it depolarizes sinus)
Which cranial nerves contribute to the carotid body (chemoreception)?
Vagus CN X and Glossopharyngeal CN IX (mostly CN IX)
Carotid sinus general characteristics.
between the media and externa are nerve fibers for baroreceptors of the carotid sinus, when the BP increases the muscle expands, sending an AP to stimulate both CN IX and CN X (mostly vagus)
CVAs are associated with occlusions of the _____ artery.
carotid
An imbalance in which minerals is thought to contribute to the development of atherosclerosis?
phosphorus, magnesium, calcium
This vein runs along the medial border of the sternohyoid muscle.
anterior jugular
This vein runs with the carotid artery in the carotid sheath.
internal jugular
These lymph nodes are found above the SCM.
superficial cervical
Plagiocephaly
assymetrical distortion of the skull, can fix this but not the torticollis in congenital cases
Atypical cervical vertebrae.
C1, C2, and C7 - contain anatomical structures/features that are unique compared to other cervical vertebrae
Atlas C1
considered most unique because it doesn’t have a vertebral body, no process present but has a tubercle, pronounced (large) vertebral foramen
Axis C2
dens - representation to certain scientist of being fused with C1
C7
vertebral prominence is a landmark to distinguish area changing from cervical to thoracic, thick transverse process with vertebral foramen that is more similar to thoracic vertebrae
The spinous process in typical cervical vertebrae is usually _____.
bifid
This non-osteological structure is easily viewed in the anterior x-ray of the cervical region.
trachea (also pharynx, sometimes esophagus)
Demarcates the posterior limits of the spinal canal.
spinolaminar line
In adults, a straight C-spine (lack of lordosis) indicates the presence of ______ ______ and a possible occult fracture.
muscle spasm
Proper positioning of the atlantoaxial bones is best seen in which x-ray view?
lateral
This x-ray view of the C-spine is particularly helpful in evaluating suspected unilateral facet dislocations since only one half of the facets and intervertebral foramina are viewed at a time. The foramina are also best visualized on these views.
oblique
This x-ray view of the C-spine could show rotary subluxation of the atlas (would need confirmed with MRI).
odontoid
Jeffereson Fx
arches may be broken in more than one piece on either side, one of the most common, must have a transection/separation of the bones in both areas, always found on the atlas
Hangman Fx
pedicles are broken on both/either side, always associated with the axis, can be a partial crack in one side (unilat.) called Linear Fx, additional trauma can affect the odontoid process (dens)
Three types of odontoid fractures.
Type I - tip of the dens; Type II - base/neck of the dens (most common); Type III - body of dens
Which nerve is vulnerable during thyroid surgery?
recurring laryngeal branches of vagus (passes behind the gland)
50% of people has a pyramidal lobe, generally found on the ___ side of the Thyroid Gland.
left (could have Grave’s disease if present)
The pyramidal lobe is actually a vestigial remnant of the ___________ tract/duct.
thyroglossal
Laryngeal apparatus
Cricoid cartilage, Thyroid cartilage, Upper 3-4 rings of the trachea, larynx is located right below the hyoid bone
Anterior layer of _______ fascia is the superficial layer of the investing fascia that has split from the stylohyoid ligament.
parotid (posterior layer of the parotid fascia is continuous with the deep layer of investing fascia and this fuses with the parotid gland)
Innervated by Ansa Cervicalis (C1-3)?
omohyoid, sternothyroid, sternohyoid
What is the most important spinal segment contribution to the phrenic nerve?
C4 (C3-C5 are roots but C4 is the most important)
Dorsal scapular nerve spinal segments?
C4 and C5
Long thoracic nerve spinal segments?
C5-C7
C1 courses along with the hypoglossal nerve (CN XII) to innervate which muscles?
geniohyoid and thyrohyoid
Suprahyoids
mylohyoid, stylohyoid, geniohyoid, digastrics
Infrahyoids
sternohyoid, omohyoid, sternothyroid, thyrohyoid
Cells of the thyroid.
simple cuboidal epithelium
Single (unpaired) cartilages of the larynx.
epiglottis, thyroid, cricoid
Paired cartilages of the larynx.
arytenoid, corniculate, cuneiform
The _____ _____ muscles interrelate with these cartilages and are considered the intrinsic muscles of the larynx.
vocal cord
Most important tensor muscle of the larynx.
cricothyroid (innervated by external branch of superior laryngeal nerve of vagus, GSE and GSA)
Laryngeal relaxers.
vocalis and thyroarytenoids
Laryngeal abductor.
posterior cricoarytenoid
Laryngeal adductors.
obliques aryepiglottic, transverse arytenoid, lateral cricoarytenoid
Nucleus for motor to pharyngeal and laryngeal muscles (CN X Vagus nerve).
nucleu ambiguus
What would occur if the posterior cricoarytenoid muscle were paralyzed (recurrent laryngeal nerve trauma)?
adducted cords, patient cannot breathe (transection of nerve will result in partially abducted/adducted cords and patient cannot speak or cough)
