Cervical Fascia and Posterior Triangle Flashcards
what are the borders of the neck?
extends anteriorly from the lower border of the mandible to the upper surface of the manubrium; posteriorly from the superior nuchal line on the occipital bone to the intervertebral disc between cervical vertebra 7 to thoracic vertebra 1
what is the Superficial Fascia of the Neck composed of? where is it located? does it contain any muscles/organs? Which, if so?
- noncontractile connective tissue
- composed of loose CT (sometimes fat filled)
- between the skin and deep fascia
- contains the platysma (thin muscle)
what are the boundaries of the platysma muscle?
attached from the superficial fascia of the thorax to the margin of the mandible
How many deep fascia compartments are there in the neck? what are their functions?
5 compartments/tubes;
provide cleavage planes, slippery surfaces facilitate the movement of structures, limit and direct the spread of infection; enclose structure
where is the investing layer located?
fasica that encloses the neck in a continuous layer, attached to bone above and below the neck:
what is enclosed by the investing layer of deep fascia?
splits to enclose the parotid and submandibular glands, the SCM, trapezius muscle, binds down the intermediate tendons of the digastric and omohyoid muscles
what are the attachments of the sternocleidomastoid muscle?
manubrium of sternum and clavicle (inferiorly); mastoid process and superior nuchal line (superiorly)
what are the actions of the SCM?
If acting ALONE: rotates the face to the opposite side while bending the head to the same side
if acting TOGETHER: flex the head and the neck
(both needed to hold the head upright)
What is the SCM innervated by?
spinal accessory nerve (CN XI); pierces the SCM en route to trapezius
What is Torticollis? What is it caused by?
wry neck ( a flexion deformity of the neck)
caused by SCM injuring during child birth due to aggressive pulling on child’s head
Need both SCM to keep the head straight
What does the pretracheal layer enclose?
visceral organs (trachea, esophagus, thyroid gland, pharynx)
what are the attachments of the pretracheal layer? (superiorly and inferiorly)
Superiorly: attaches to the laryngeal cartilages and hyoid bone
Inferiorly: descends anteriorly to the trachea to fuse with the fibrous pericardium
why does the thyroid move with the larynx during swallowing?
Because the pretracheal layer of fascia attaches to both the thyroid gland and the larynx
Where is the Prevertebral fascial layer located?
anterior to the cervical vertebrae; prolongs into the axilla as a sheath for the brachial plexus
What does the carotid sheath enclose?
common carotid, the interjugular vein, and the vagus nerve
In the carotid sheath, the Vagus nerve lies _______ and _____ the artery and vein
behind and between
The carotid fascia lies _____ (thick/thin) over the artery and _____(thick/thin) over the vein, this allows for _________.
thick over the artery, thin over the vein, allows for venous dilation
what other layers of the deep fascia is the carotid sheath continuous with?
continuous with the investing, pretracheal, and prevertebral layers
Where is the buccopharyngeal fascia located?
it is the posterior portion of the pretracheal fascia;
what does the buccopharyngeal fascia separate?
the pharynx and esophagus from the prevertebral fascia
what are the boundaries of the buccopharyngeal fascia?
begins superiorly at the base of the skull and ends inferiorly in the thoracic cavity
what is a fascial space? what is it’s function
are potential spaces that exist between the fascia and underlying organs and other tissues.[3] In health, these spaces do not exist, they are only created by pathology. E.g. the spread of pus or cellulitis in an infection. The fascial spaces can also be opened during the dissection of a cadaver. The fascial spaces are different from the fascia itself, which are bands of connective tissue that surrounds structures, e.g. muscles
where is the retropharyngeal space located
between the buccopharyngeal fascia and the prevertebral fascia
what is the retropharyngeal space
potential space filled with loose CT
what is the function of retropharyngeal space
facilitates movement of the pharynx and larynx during swallowing;
what can happen if an abscess posterior to the prevertebral fascia enters the retropharyngeal space?
it can impinge on the esophagus, causing dysphagia (difficult to swallow) and potentially extend into the posterior mediastinum
where is the pretracheal space located?
potential space between the investing layer (covering posterior sides of infra hyoid muscles) and anterior sides of pretracheal fascia
what is the anterior boundary of the posterior triangle of the neck?
posterior border of the SCM
what is the posterior boundary of the posterior triangle of the neck?
anterior border of the trapezius
what is the inferior boundary of the posterior triangle of the neck?
clavicle
what is the superior boundary of the posterior triangle of the neck?
angle where the SCM and trapezius meet on the superior nuchal line of the occipital bone
what is the roof of the posterior triangle of the neck?
the investing layer of the cervical fascia, platysma, external jugular vein
what is the floor of the posterior triangle of the neck?
levator scapulae and scalene muscles, covered by prevertebral fascia
what are the scalene muscles? what is their attachment site?
a group of small muscles, attached to the transverse process of the ribs;
three of them: anterior middle and posterior scalene muscles
what divides the posterior triangle of the neck?
the inferior belly of the omohyoid into the subclavian and occipital triangles
Where do the contents of the posterior triangle of the neck travel to?
to the upper limb
where do the contents of the anterior triangle of the neck travel to?
thorax
What are the contents of the posterior triangle?
- roots of brachial plexus
- accessory nerve
- cervical plexus
- external jugular vein
- subclavian artery and some of its branches
- lymphnodes
what forms the axilla sheath?
prevertebral fascia
what branches of the brachial plexus can be found in the posterior triangle of the neck?
- dorsal scapular
- suprascapular
- nerve to subclavius
- long thoracic
NOT THE PHRENIC!!
what is nerve block/point of anesthesia in the posterior triangle do?
blocks the nerves of the brachial plexus (provides anesthesia to the upper limb)
where do the roots of the brachial plexus emerge in the posterior triangle of the neck?
from the interval between the scalenus anterior and the scalenus medius muscle; trunks are formed in the posterior triangle
what is the path of the accessory nerve in the posterior triangle of the neck?
emerges at the junction of the superior and middle thirds of the SCM, crosses the posterior triangle obliquely, superficial to the prevertebral fascia, and enters deep to the anterior border of the trapezius at the junction of the upper 2/3 and lower 1/3rd
what does the accessory nerve (CN XI) innervate?
the SCM and trapezius muscles
what does paralysis of CN XI result in? is it common? why?
CN XI (accessory) is superficial and vulnerable to injury; injury results in paralysis of the trapezius muscle = drooping in the shoulder, inability to shrug on the affected side, and difficulty in abduction of the arm above 120 degrees.
What rami is the cervical plexus formed by?
ventral rami C1-4;
where is the cervical plexus located?
located deep to SCM = NOT IN POSTERIOR TRIANGLE!
what vental rami is the lesser occipital nerve formed by?
C2 C3
what vental rami is the greater auricular nerve formed by
C2 C3
what vental rami is the transverse cervical nerve formed by?
C2 C3
what vental rami is the supraclavicular nerve formed by?
C 3 C4
why is the lateral/posterior area of the neck a common point of anesthesia
the cervical plexus branches are located there and will provide blocking of the nerves (anesthesia) to the extensive area of the neck
where do the motor nerves that are located in the posterior triangle of the neck travel to?
- to prevertebral muscles
- to infrahyoid muscles by ansa cervicalis
- to diaphragm via phrenic nerve (C3,4,5 keep the diaphragm alive!)
how is the ansa cervicalis formed? (via what nerves?)
superior root (C1 fibers) course with the hypoglossal nerve (XII) and join the inferior root (C2,3) to form the ansa cervicalis (ansa = circle)
where do motor branches of the ansa cervicalis innervate? what nerve to they arise from/travel with?
innervate the thyrohyoid and geniohyoid;
arise from hypoglossal nerve but they are C1 fibers traveling with the cranial nerve
what vein drains most of the tissues of the posterior triangle?
external jugular vein
what veins is the external jugular vein form by?
union of the posterior auricular vein and a branch of the retromandibular vein
what is the course of travel of the external jugular vein?
- crosses the SCM obliquely, deep to the platysma;
- pierces the investing layer of deep fascia above the clavicle at the antero-inferior angle of the posterior triangle, and enters the subclavian vein
The ______ and _______ pass between the anterior and middle scalenes
brachial plexus and subclavian artery
The______ and _______ pass anteriorly to the anterior scalene as the muscle crosses over the first rib
subclavian vein and phrenic nerve
what are the boundaries of the three divisions of the subclavian artery?
1st part: From its origin to the medial border of scalenus anterior
2nd part: Lying behind scalenus anterior
3rd part: Between the lateral border of scalenus anterior and the outer border of the first rib
** subclavian muscle travels between the anterior and medius scalenus muscle (only the 2nd part is actually behind the anterios scalenus)
what part of the subclavian artery is located in the posterior triangle of the neck
the 3rd part; enters the antero-inferior part of the posterior triangle, and then disappears behind the middle of the clavicle, joining the cords of the brachial plexus
where is the subclavian vein located? relative to the subclavian artery; does it enter the posterior triangle of the neck?
-lies below and in front of the third part of the artery, behind the clavicle;
crosses ANTERIOR to anterior scalenus muscle
-DOES NOT ENTER THE POSTERIOR TRIANGLE
where are central lines for IVs often placed?
in the subclavian vein, where it crosses the anterior scalenus
what are the branches of the subclavian artery?
VITamin C and D:
V: Vertebral
I: Interior thoracic
T: Thyrocervical trunk
C: Costocervical trunk
D: Dorsal Scapular
on the left, where do the branches of the subclavian artery arise from ?
all of them from the first part, except for dorsal scapular
where does the costocervical trunk arise from on the right?
from the second part of the subclavian artery
where does the dorsal scapular artery arise from? what is its course of travel?
arises from the 2nd or 3rd part of the subclavian artery;
passes through the trunks of the brachial plexus to supply the rhoboids
what are the branches of the thyrocervical trunk?
- Inferior thyroid artery
- transverse cervical artery
- suprascapular artery
which branches of the thryocervical trunk cross the posterior triangle of the neck?
transverse cervical artery and suprascapular artery
what does the transverse cervical artery supply?
trapezius
from what artery does the occipital artery branch off of?
branches off of the external carotid artery
what is the travel course of the occipital artery?
crosses the posterior triangle at its superior angle, ascends on the back of the scalp with the greater occipital nerve
__________ lymph nodes form a chain along the external jugular vein; _______ lymph nodes form a chain along the internal jugular vein
superficial cervical; deep cervical
where does lymph from the superficial cervical nodes eventually drain into?
the deep cervical lymph nodes
where is the jugulo-digastric located?
where the posterior belly of digastric crosses internal jugular vein
where is the jugulo-omohyoid located?
inferior to the intermediate tendon of omohyoid and internal jugular vein
where do deep cervical lymph nodes drain lymph into?
into either the right lymphatic duct (right side) or directly into the thoracic duct on the left side
what is the thyroid gland and what does it secrete?
an endocrine gland that secretes thyroxin, which stimulates catabolism of glucose, fates and proteins, which are e3ssential for normal growth
does the thyroid gland have a true fibrous capsule intimately attached to it?
yep!
what is the false capsule of the thyroid formed by?
pretracheal fascia
what anchors the thyroid gland to the thyroid and cricoid cartilages?
suspensory ligaments
what tracheal rings does the thyroid isthmus cover?
rings 2-4
what are the boundaries of the thyroid lobes?
extends from the 6th tracheal ring to the oblique line of the thyroid cartilage
what prevents upward enlargement of the thyroid gland?
the attachment of the sternothyroid muscle
what is the pyramidal lobe?
a small prominence on the superior border of the isthmus, usually on the left side; represents a distal part of the thryoglossal duct that didn’t fully regress during development
what defines the antero-lateral border of the thyroid gland?
strap muscles and overlapping SCM
what defines the postero-medial border of the thyroid gland?
related to the esophagus and trachea; the recurrent and external laryngeal nerves;
posterior aspect contains the parathyroid glands
when does the thyroid gland enlarge?
during pregnancy and menstruation
what are the arterial supplies of the thyroid gland?
- superior thyroid artery
- inferior thyroid artery
- thyroidea ima
what does the superior thyroid artery run with?
the external laryngeal nerve
what does the inferior thyroid artery run with?
the recurrent laryngeal nerve
what are the venous drainage of the thyroid gland?
-superior thyroid vein
-middle thyroid vein
-inferior thyroid vein
(superior and middle thyroid veins drain into the internal jugular vein; inferior thyroid vein drains into the brachiocephalic trunk)
what is the lymphatic drainage of the thyroid?
to deep cervical nodes, pre-laryngeal and pre-tracheal nodes
what is the function of the sympathetic nerve fibers of the thyroid gland
vasomotor to blood vessels
what is an ectopic thyroid (lingual thyroid)
if the thryoglossal duct does not fully descend during development
what is a goiter? what is it caused by?
its is a non-neoplastic (not associated with overproduction of thyroid hormone or malignancy)enlargement of the thyroid;
caused by iodine deficiency
what does unilateral damage to the recurrent laryngeal nerve result in?
hoarseness/damage to vocal quality
what does damage to the external laryngeal nerve result in?
monotonous (unilateral) voice
what are parathyroid glands?
pea-sized endocrine glands essential for the control of calcium metabolism
where are the parathyroid glands located?
2 pairs (one pair --inferior and superior-- per lobe) located on the posterior aspect of the thyroid between capsule and pretracheal fascia; near the point of entry of the inferior thyroid artery
what is the major source of blood supply to the parathyroid gland? what is their main innervation?
blood supply: inferior thyroid artery
innervation: sympathetic vasomotor fibers
what is an ectopic (aberrant) thyroid?
if the parathyroid gland remain with the thymus during development; the parathyroid gland still secretes hormones though!
