Anatomy Neck Flashcards
anterior triangle borders
inferior border of mandible
anterior border of SCM
line down the midline of the neck
investing fascia covers the roof
anterior triangle contents
suprahyoid muscles, infrahyoid muscles, common carotid artery, external and internal carotid arteries, internal jugular vein
cranial nerves 7 (facial), 9 (glossopharyngeal), 10 (vagus), 11 (accessory), 12 (hypoglossal)
what structure bifurcates in anterior triangle
common carotid artery (bifurcates at superior border of thyroid cartilage)
what are the suprahyoid muscles
stylohyoid, mylohyoid, geniohyoid, digastric
what are the infrahyoid muscles
omohyoid, sternohyoid, thyrohyoid, sternothyroid
anterior triangle subdivisions
carotid, submental, submandibular, muscular triangles
carotid triangle contents
common carotid artery with branches, internal jugular vein, hypoglossal nerve, vagus nerve
also has carotid sinus (dilated portion of common carotid and internal carotid that has baroreceptors), glossopharyngeal nerve transmits signal to brain when stretch detected
submental triangle contents
submental lymph nodes (filter lymph from floor of mouth and parts of tongue)
submandibular triangle contents
submandibular (salivary) gland, lymph nodes, facial artery and vein
muscular triangle contents
infrahyoid muscles, pharynx, thyroid, parathyroids
posterior triangle borders
posterior border of SCM
anterior border of trapezius
middle 1/3 of clavicle
posterior triangle major contents
omohyoid (crosses it to reach anterior triangle), external jugular vein empties into subclavian vein within triangle, transverse cervical artery and vein, suprascapular artery and vein, subclavian artery, accessory nerve, cervical plexus with phrenic nerve as branch, brachial plexus
cervical plexus nerve block
“nerve point” of neck
used for local anesthesia of neck
injected along posterior border of SCM at the junction of its superior and middle thirds, this is where the cutaneous branches of the cervical plexus emerge
number of cervical vertebrae
7
C1 name
atlas
C2 name
axis
what joint allows head flexion (nodding)
atlanto-occipital joint
between the superior facets of the atlas and the occipital condyles of the cranium base
jefferson fracture of atlas
vertical fall on neck (diving in shallow water)
transverse ligament of atlas may be ruptured
Since the vertebral foramen is large, it is unlikely that there will be damage to the spinal cord at the C1 level. However, there may be damage further down the vertebral column
hyperextension (whiplash) injury
anterior longitudinal ligament of the spine is damaged
vertebral foramen is large so there is less chance of spinal cord involvement
dislocation or subluxation of cervical vertebrae may occur with spinal cord involvement
Hangman’s Fracture
fracture of the pars interarticularis (bony column between the superior and inferior articular facets of the axis)
spinal cord rupture (deep unconsciousness, respiratory and cardiac failure)
hyoid bone fracture is a characteristic finding in what
strangulation
waldeyer’s ring
ring of lymphoid tissue in nasopharynx and oropharynx formed by the pair of palatine tonsils, lingual tonsils and adenoid tonsils
pharyngeal pouch (diverticulum)
pathophysiology
presentation
when swallowing thyropharyngeus muscle should contract while cricopharyngeus should relax
if this coordinated relaxation did not occur, intrapharyngeal pressure rises and pharyngeal mucosa forms a midline diverticulum between the 2 muscles
dysphagia and bad oral smell due to accumulation of food
NB: these muscles are inferior pharyngeal constrictors
motor innervation of pharyngeal muscles
vagus nerve
EXCEPT stylopharyngeus by glossopharyngeal nerve
pharyngeal muscles 2 groups and function
circular muscles: superior, middle, inferior pharyngeal constrictors –> contract sequentially to propel food downwards
longitudinal muscles: stylo- , palato- , salpingo- pharyngeus –> shorten and widen pharynx, elevate larynx when swallowing
sensory innervation of pharynx
blood supply
glossopharyngeal nerve
branches of external carotid artery (ascending pharyngeal artery)
cricoid cartilage location spinal cord
C6
intrinsic muscles of larynx function and innervation
control vocal cords
all innervated by recurrent laryngeal nerve EXCEPT cricothyroid muscle by superior/external laryngeal nerve
recurrent laryngeal nerve palsy causes
thyroid cancer apical lung tumor aortic aneurysm cervical lymphadenopathy thyroid surgery
unilateral RLN injury
hoarseness
bilateral RLN injury
vocal cords paralysis in adduction position, breathing impaired, emergency
what is Adam’s apple
laryngeal prominence on thyroid cartilage
cricoid cartilage importance
marks the inferior border of the larynx
the only complete circle of cartilage in larynx or trachea
during emergency intubation, pressure can be applied to cricoid cartilage to occlude esophagus and prevent regurgitation (cricoid pressure or Sellick’s maneuvre)
thyroid vertebrae span, what does it cover
C5 - T1, it wraps around cricoid cartilage and superior rings of trachea
what is the visceral compartment of the neck
compartment bound by pretracheal fascia
consists of trachea, thyroid, esophagus, pharynx
thyroglossal cyst etiology
developing thyroid descends from base of tongue (foramen cecum) to anterior neck
during descent, it forms thyroglossal duct which regresses
if duct persists it can cyst due to build-up of secretions
thyroglossal cyst presentation
midline lump in neck which rises on tongue protrusion
carotid sheath contents
common carotid artery, internal jugular vein, vagus nerve
what muscles cover the thyroid anteriorly
infrahyoid muscles
sternohyoid, sternothyroid, thyrohyoid and omohyoid
arterial supply of thyroid
superior thyroid: 1st branch of external carotid artery
inferior thyroid: thyrocervical trunk (branch of subclavian)
in 10% of people, thyroid ima artery: brachiocephalic trunk
Superior thyroid artery is close to what nerve
superior laryngeal nerve
inferior thyroid artery is close to what nerve
recurrent laryngeal nerve
venous drainage of thyroid
superior, middle veins: internal jugular vein
inferior vein: brachiocephalic vein
lymphatic drainage of thyroid
paratracheal and deep cervical nodes
pathway of right RLN
vagus nerve hooks around the right subclavian artery then into the tracheoesophageal groove and passes under the thyroid
pathway of left RLN
vagus hooks around aortic arch then into the tracheoesophageal groove and passes under the thyroid
parathyroid origin
superior from 4th pharyngeal pouch
inferior from 3rd pharyngeal pouch
parathyroid arterial supply and venous drainage
inferior thyroid artery (supplies posterior aspect of thyroid)
3 thyroid veins
phrenic nerve spinal roots
C 3-4-5 keeps diaphragm alive
cervical plexus spinal roots
C1 - C4
greater auricular nerve sensation
external ear and skin over parotid
Carotid sinus vs carotid body
Sinus: enlargement of common carotid artery and internal carotid artery at bifurcation, baroreceptors, detect stretch —> increased BP (glossopharyngeal nerve relays msg to brain)
Body: external to carotid sinus, peripheral chemoreceptors, detect O2 content in blood to regulate RR
External carotid artery supplies
Head/face and neck external to cranium (extra cranial structures)
External carotid artery branches
Superior thyroid artery Lingual artery Facial artery Ascending pharyngeal artery Occipital artery Posterior auricular artery
Right common carotid artery origin
Branch of brachiocephalic trunk (subclavian second branch)
Left common carotid artery origin
Aortic arch
Internal carotid artery supplies
Brain, eyes, forehead (intra cranial structures)
Pterion fracture
Weakest point of skull
Middle meningeal artery damage or complete laceration
Extradutal hematoma (between dura and skull), increases ICP
Mild: diuretics
Severe: burr holes
Atherosclerosis of carotid arteries pathology, Location
Features
Imaging, treatment
Swelling at carotid sinus causes turbulent blood flow, internal carotid artery most susceptible
Atherosclerotic thickening of walls reduces blood flow
headache, dizziness, muscular weakness - stroke if complete occlusion
Doppler, carotid endarterectomy
