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