Neck - Bones, Fasciae, and Posterior Triangle Flashcards
Importance of the neck?
Conduit for important structures from the head to the body
The bones of the neck do what?
Support the head and provide flexibility
Where is the hyoid bone found?
C3 level
Which bone doesn’t articulate with any other bones?
hyoid bone
The hyoid bone is suspended by?
stylohyoid ligament
what are the atypical cervical vertebrae?
C1, C2, C7
What is unique to the cervical vertebrae?
Transverse foramen in the transverse processes
The spinal cord is largest in which region?
Cervical
The uncinate processes are located where?
Laterally (superolaterally)
Where is the carotid tubercle?
C6
What’s unique about the spinous processes in cerical vertebrae?
Short and bifid
What population especially has short and bifid spinous processes?
White males
What’s unique to C7?
Spinous process is long and it is usually not bifid
What’s unique to the facet joints in the cervical vertebrae?
They slope superiorly
What is the significance of the superior slope of the facet joints?
Doesn’t allow for rotational movements, but allows for flexion/extension and some lateral flexion
Which vertebrae is the atlas?
C1
Which vertebrae is the axis?
C2
Which vertebrae supports the weight of the cranium?
C1
What is the significance of the transverse ligament of C1?
Holds the dens of C2 in place
What is unique to the C1 shape?
It doesn’t have a body or spinous process
Lateral masses of C1 do what?
Support the occipital condyles of the cranium
Where is the transverse ligament found?
between the lateral masses of C1
What causes the “yes” gesture?
Rocking on the occipital condyles of C1
What causes the “no” gesture?
Rotation of C2
Which is the strongest cervical vertebrae?
C2
The dens is also known as what?
Ondontoid process
Where is the vertebral foramen the smallest? and why?
C7
It only holds the vertebral vein, the vertebral artery goes up C6
Which joint provides rotational movement of the cervical spine?
Atlanto-axial joint (C1 and C2)
What creates the angle between the mandible and the thyroid cartilage?
Hyoid bone
What parts make up the hyoid bone?
body, greater and lesser horns
What is the significance of the hyoid bone?
Adds rigidity to the airway (which is prone to collapse because of pressure) and provides attachments for cervical muscles
Layers of the cervical fascias?
Superficial layer
Investing-Pretracheal-Prevertebral
What allows the structures of the neck to glide against each other?
Cervical fascia
What fascia layer circumferentially surrounds the neck and contains the platysma and external jugular vein?
Superficial fascia
What nerve innervates the platysma?
CN VII - cervical branch of the facial nerve
Where is the external jugular vein located?
Deep to the platysma muscle
What muscle in the neck contributes to facial expression?
Platysma
What are the three deep columns of the cervical fascia?
Investing
Pretracheal
Prevertebral
What does the cervical fascia do?
Compartmentalizes muscles and viscera
Conduit for neurovascular structures
Allows the structures to glide off of each other
Which cervical fascia layer is deep to the dermis?
Superficial fascia
Where is the superficial fascia found?
circumferentially surrounding the neck
What does the superficial fascia contain?
Platysma and external jugular vein (anterolaterally)
What nerve innervates the superficial fascia?
Cervical branch of the facial nerve (CN VII)
Which muscle originates on the mandible and its insertion blends in with the pectoral fascia below the clavicle?
Platysma
Where is the investing cervical fascia found?
Surrounding the entire neck
Which muscles do the investing fascia envelope?
SCM and trapezius
Which two muscles have nearly continusous origins and insertions?
SCM and trapezius
The SCM is innervated by what?
CN XI, spinal accessory nerve
The trapezius is innervated by what?
CN XI, spinal accessory nerve
What, besides muscles, does the investing fascia also develop?
submandibular and parotid glands
Which cervical deep fascia layer invests the muscles and viscera in the anterior neck?
Pretracheal
The pretracheal deep cervical fascia extends from where to where?
From hyoid to the pericardium of the heart
The intermediate tendons of the pretracheal fascia form what? Which muscles does that involve?
pulleys; digastric and omohyoid
The muscular portion of the pretrachial fascia invests what?
infrahyoid muscles
The visceral portion of the pretracheal fascia invests what?
Thyroid, trachea, and esophagus
Which portion (muscular and visceral) of the pretrachial fascia are thick and thin?
Muscular - thin
Visceral - thick
Superiorly, the pretrachial fascia becomes what? Inferiorly?
Buccopharyngeal fascia
Fibrous pericardium
What is the buccopharyngeal fascia?
Extension of the pretrachial fascia superiorly (out of the neck region) in the head
The prevertebral fascia surrounds what?
vertebral column and associated muscles
The carotid sheath is made up of what?
The investing, pretrachial, and prevertebral fascia
Where does the carotid sheath extend?
Extends from the cranial base to the root of the neck
What does the carotid sheath contain?
Common/external/internal carotids, internal jugular, Vagus nerve (CN X), nerve to carotid sinus, carotid arterial plexuses (postganglionic sympathetic neurons)
What is the potential space called in the cervical fascia? What is its significance?
Retropharyngeal space; this is the danger zone; if an infection from the buccopharyngeal fascia gets in here, there’s no stopping it from spreading down to the pericardium
Where is the retropharyngeal space found? What is in it?
Between the pretracheal and prevertebral sheaths
loose areolar connective tissue
What divides the retropharyngeal space?
alar fascia
What areas are closed/opened to the retropharyngeal spaces? Why is this significant?
Closed at cranial base superiorly and the carotid sheath laterally
Open to the posterior mediastinum inferiorly
Infections that get in here cannot ascend, but they can descend into the mediastinum
How is the superficial neck divided?
Into 2?
Into 4?
Between the mandible and the clavicle, the trapezius and the midline of the neck make up the superficial neck area.
The SCM divides this area into two triangles - anterior and posterior
The inferior belly of the omohyoid muscle divides this again into 4 triangles - submandibular, submental, carotid, and muscular triangles
Which areas make up the posterior triangle of the neck?
occipital triangle (between trapezius, SCM, and omohyoid) omoclavicular (between SCM, omohyoid, and clavicle)
Origin of SCM?
mastoid process
Insertion(s) of SCM?
Manubrium (sternal head)
Medial 1/3 of clavicle (clavicular head)
Actions of SCM?
Extension of the head, flexion of the cervical spine, laterally flexes (ipsilateral side), rotates the head (contralaterally)
SCM innervation?
CN XI spinal accessory nerve
Where is the supraclavicular fossa found? Why is this significant?
Between the SCM heads
This is a landmark for a jugular vein approch for a central line
Which neurovascular structures run with SCM?
Superior 1/2 of external jugular vein, great auricular nerve, the transverse cervical crosses the midpoint of the muscle, lesser occipital parallels the posterior border of SCM
The neck is mostly supplied by what kind of nerves?
Spinal nerves
The face anterior to the ears are supplied by what kinds of nerves?
Cranial nerves
Most superficial posterior neck muscle?
Trapezius
Trapezius origin?
Superior nuchal line, nuchal ligament, spinous processes C7-T12
Trapezius insertion?
lateral 1/3 of clavicle, acromion, spine of scapula
Trapezius innervations?
CN XI
Cutaneous innervation of the posterior neck is supplied by?
C2 (greater occipital) C3 (least occipital), C4
Which nerve crosses the posterior triangle to reach trapezius?
CN XI spinal accessory nerve
Between which two muscles is the posterior triangle of the neck found?
Superior and inferior parts of the triangle?
posterior border of SCM and the anterior border of trapezius
Superior (apex) SCM and trapezius union at the mastoid process
Inferior middle 1/3 of the clavicle
What makes up the floor of the posterior triangle of the neck?
Prevertebral fascia and the middle and posterior scalene, levator scapulae, and splenius capitus
What musle divides the posterior triangle inferiorly? What does it divide it into?
inferior belly of omohyoid muscle dividies into occipital and omoclavicular triangles
The occipital artery is found where?
Apex of the occipital triangle of the posterior triangle of the neck
The occipital artery is a branch off of what?
External carotid
The Suprascapular artery is a branch off os what?
thyrocervical trunk
Where is the suprascapular artery found?
Base of the omoclavicular triangle
Suprascapular artery is found in what relation to the phrenic nerve and the brachial plexus?
Superficially
What does the suprascapular artery supply?
muscles of the posterior shoulder
The transverse cervical artery is a branch off of what?
Thryocervical trunk
Where is the transverse cervical artery found?
At the base of the occipital triangle, crossing anterior scalene
The transverse cervical artery can divide into what?
superificial and deep (dorsal scapular) branches
If the transverse cervical artery doesn’t branch, where is the dorsal scapular artery usually found?
Branching off the subclavian
The phrenic nerve is found underneath what?
Transverse and suprascapular arteries
The subclavian artery emerges between which muscles?
Anterior and middle and posterior scalenes
What artery crosses over the 1st rib to become axillary?
Subclavian
The roots of the brachial plexus and the subclavian artery come through what?
Scalene triangle
Where does the external jugular vein enter the occipital triangle?
Posterior border of SCM
From what two veins does the external jugular come to be?
Retromandibular and posterior auricular
The subclavian vein crosses what?
The omoclavicular triangle anterior to the anterior scalene
The cervical plexus is formed from what ventral rami?
C1-C4
Sensory branches of the cervical plexus course which way (at least initially)?
Posteriorly
Motor branches of the cervical plexus course which way (initially)?
anteriorly
What cranial nerve becomes indistinguishable from C1?
CN XII, hypoglossal nerve
What nerves make up ana cervicalis?
C1 and C2
Superior root of ansa cervicalis is supplied by what nerves?
C1 and C2
What is the inferior root of ansa cervicalis made up of?
C2
What muscles does C1 go on to innervate?
Geniohyoid and thyrohyoid
The branches of inferior ansa innervate what muscles?
3 of the infrahyoid muscles: omohyoid, sternohyoid, sternothyroid
Transverse cervical is make up of what nerve?
C2
Greater auricular nerve and the lesser occipital nerve arise from what nerve?
C2
What nerve does the supraclavicular nerve come off of?
C3
What nerves make up the phrenic nerve?
C3-C5
Supraclavicular has how many branches?
3; anterior, middle, posterior
The greater auricular nerve courses with what? What does it supply?
External jugular vein to supply posterior auricle and parotid region (between mastoid process and the mandible angle)
What does the transverse cervical nerve innervate?
anterior cervical region
What doe sthe lesser occipital nerve supply? And what muscle does it parallel?
Supplies posterolateral neck and scalp; parallels posterolateral neck and scalp
What does the supraclavicular nerve supply?
clavicular skin and shoulder
The phrenic nerve does what?
Motor supply to diaphragm and visceral afferents from pericardium, pleura, etc.
The C4-C5 loop of the cervical plexus also contributes motor fibers to what?
dorsal scapular (C4,C5), long thoracic (C5) of the brachial plexus
The nerve point in the neck is also called what?
Erb’s point
The spinal acessory nerve crosses the occipital triangle where?
Inferolaterally
CN XI (spinal accessory) is the only motor nerve that ?
is found superficial to the prevertebral fascia
Cutaneous branches of the cervical plexus emerge where?
Posterior midpoint of SCM
What nerves are found in the nerve point of the neck?
Lesser occipital, great auricular, transverse cervical, supraclavicular
Which cervical nerves make up the superior trunk of the brachial plexus?
C5 and C6
Which nerve crosses the occipital triangle laterally?
Suprascapular
When a cervical dislocation happens, what happens to the vertebrae?
The superior vertebrae displace anteriorly
In slight cervical dislocations, why is the there not as bad spinal cord damage?
Because the size of the vertebral foramen gives space for the cord
What constitutes a cervical true dislocation?
“jumped facets,” when the inferior facet of the superior vertebrae is pushed anteriorly to the inferior vertebrae’s superior facet
A subluxation is defined as what? Why is this not a true dislocation?
when the inferior facet has jumped anteriorly, but it’s only a complete dislocation if the inferior facet has jumped so anteriorly it crosses the superior facet of the inferior vertebrae
Why would you need an MRI to show the extend of a cervical dislocation?
Because it can see soft tissue damage; sprains and sublxations may self-reduce
A Jefferson fracture is also known as what? What is it? Why does this happen?
Burst fracture; fracture of the anterior and posterior arches of C1; vertical compression injury (diving accidents)
Why may a spinal cord injury not occur in a Jefferson fracture?
Because it widens the vertebral foramen (the lateral masses are pushed aside)
In what case is a CNS injury more likely in a Jefferson fracture?
When the transverse ligament ruptures
What is a hangman’s fracture?
Fracture to C2 between the pedicle and the lamina by forced hyperextension of the head
Why is a hangman’s fracture more severe? What can happen as a result?
The body of C2 subluxates anteriorly, separating it from its facet
Quadriplegia, death
What are the three types of dens fractures? Which has the best prognosis?
Type I - fracture of the upper part of the dens
Type II - fracture at the base of the dens
Type III - fracture of the dens and a part of C2 body
Type III has the best prognosis; the other two are unstable
If C1 and C2 subluxate together is that better or worse?
Better, less likely to compress the spinal cord
If the transverse ligament ruptures without a dens fracture, is that better or worse?
Worse becaues C1 subluxates alone, making spinal cord compression more likely
Sign of retropharyngeal abscess?
Bulge posterior to SCM
What would you look for on an X-ray or MRi for a retropharyngeal abscess?
Thickening of the soft tissue - swelling in the prevertebral space
