anterior cervical region of the neck Flashcards
surface landmarks of the neck
mandible hyoid bone thyroid and cricoid cartilage suprasternal/jugular notch clavicle and first rib cervical vertebrae
4 layers of neck fascia
- investing layer–encloses superficial muscles and roof of neck triangles, extends from mandible to clavicle and sternum
- pretracheal layer–encloses thyroid, trachea, pharynx, esophagus
- prevertebral layer–encloses vertebral column and assoc muscles, also brachial plexus and axillary vessels
- carotid sheath–encloses common carotid and its branches, internal jugular vein, CN X, deep cervical nodes
what bisects the neck into anterior and posterior triangles?
sternocleidomastoid
boundaries of anterior cervical triangle
anterior edge of SCM
lower border of mandible body
midline of neck from chin to suprasternal notch
4 triangles of anterior cervical triangle
- submandibular (digastric)
- carotid
- submental
- muscular
submandibular triangle
body of the mandible and anterior and posterior bellies of digastric muscle (submandibular gland, CN XII, facial artery and vein, submandibular lymph nodes)
carotid triangle
upper anterior edge of SCM, posterior belly of digastric, superior belly of omohyoid (common carotid and branches, internal jugular vein, X, XI, XII)
submental triangle
unpaired, midline of neck, hyoid, anterior belly of both digastric muscles (sublingual gland, anterior jugular veins, submental lymph nodes)
muscular triangle
midline of neck, anterior edge superior belly omohyoid, anterior lower SCM (infrahyoid muscles, ansa cervicalis superficially and thyroid gland and viscera are deep)
function of infrahyoid muscles
lower the larynx and hyoid bone and fix the hyoid for stable movement of tongue
infrahyoid muscles
sternohyoid
omohyoid
sternothyroid
thyrohyoid
sternohyoid
between sternum and hyoid
omohyoid
from superior border of scapula to hyoid with superior and inferior bellies
sternothyroid
deep to the omohyoid from sternum to thyroid cartilage
thyrohyoid
deep from thyroid cartilage to hyoid
supplied by C1 via CN XII
which muscles are innervated by the ansa cervicalis originating from the cervical plexus?
sternohyoid
omohyoid
sternothryoid
roots of ansa cervicalis
anterior/superior (descendens hypoglossi)
posterior/inferior (descendens cervicalis)
the anterior root of the ansa cervicalis is associated with which cranial nerve?
CN XII by a common connective tissue sheath
how does the anterior root of the ansa cervicalis join the posterior?
it descends on the anteromedial aspect of the internal jugular and joins the posterior root forming a loop around the internal jugular
how do the motor branches from the ansa cervicalis enter the strap muscles?
caudally (surgical reflection should be done in a cranial to caudal direction)
suprahyoid muscles
- muscles attached to hyoid bone
- anterior and posterior bellies of digastric
- stylohyoid
- mylohyoid
- geniohyoid
how are the suprahyoid muscles innervated?
by cranial nerves, not the nerves of the cervical plexus
anterior and posterior bellies of digastric
separated by a tendon that attaches to the hyoid bone.
- origin from mastoid process to hyoid bone to mandible for insertion
- posterior belly supplied by CN VII
- anterior belly supplied by CN V
stylohyoid
origin from styloid process splits around tendon of digastric muscle to attach to hyoid
-supplied by CN VII
mylohyoid
arises from inside body of mandible
- forms floor of the digastric triangle and attaching to hyoid
- supplied by CN V
geniohyoid
arises from inferior mental spine of mandible and inserts on body of hyoid bone supplied by C1 via CN XII
carotid sheath
neurovascular envelope that extends from base of skull to root of neck
common carotid artery
-bifurcates into internal and external at angle of mandible
carotid sinus
small dilation at bifurcation of internal carotid
-baroreceptor area
carotid body
area of common carotid that has chemoreceptors to monitor O2/CO2 levels in blood
carotid sinus and body are innervated by?
Hering’s nerve, a branch of the glossopharyngeal nerve
branches of external carotid
superior thyroid ascending pharyngeal lingual facial occipital posterior auricular
superior thyroid
- descends toward the thyroid gland and gives off the superior laryngeal artery that pierces the thyrohyoid membrane to supply the vestibular part of the larynx (with internal laryngeal nerve of superior laryngeal nerve of X)
- parent superior thyroid artery descends further to thyroid gland with external laryngeal nerve of superior laryngeal nerve of X
ascending pharyngeal
- small
- arises from deep surface of external carotid and courses cranially on posterolateral wall of pharynx
lingual artery
arises anteriorly at level of hyoid
ascends and courses partly with hypoglossal nerve
-at lateral border of hyoglossus muscle the artery passes deep and the XII nerve superficial to hyoglossus muscle
facial artery
may arise from common trunk with lingual
ascends deep to stylohyoid and digastric muscle and submandibular gland to inferior border of mandible to the face (terminates as the angular artery)
occipital artery
- arises posteriorly opposite of facial artery
- ascends deep to posterior belly of digastric
- gives branch to SCM and then reaches posterior aspect of scalp with greater occipital nerve (DPR of C2)
posterior auricular artery
small branch arising posteriorly to distribute behind ear
two terminal branches of external carotid
superficial temporal
maxillary arteries
internal jugular vein
-continuation of sigmoid sinus
-exits skull via jugular foramen
-most superficial structure of carotid sheath
-
what drains into the internal jugular?
facial and anterior division of retromandibular vein
there is no _____ artery but there is a ____ vein
middle thyroid
brachiocephalic vein is made by?
at base of neck the internal jugular and subclavian unite to form it
vagus nerve
-exits skull thru jugular foramen to come behind and between internal carotid and internal jugular
what arises from vagus and divides into internal and external branches?
superior laryngeal branch
internal branch of vagus
sensory to larynx above vocal folds
external branch of vagus
motor to cricothyroid and circopharyngeus muscles
what supplies all the intrinsic muscles of the larynx except the cricothyroid and cricopharyngeus?
vagus
location of cervical sympathetic trunk
lie deep and medial to carotid sheath on prevertebral fascia related to the anterior surfaces of the bodies of cervical vertebrae
superior cervical ganglion
- large
- associated with first 2 vertebrae
- gray rami communicate with upper four cervical nerves
- many branches to internal and external carotids for distribution to various structures in the head
middle cervical ganglion
- at level of CV 6
- gray rami communicate with VPR C5, 6
- communicates with inferior ganglion by fibers that pass behind the subclavian artery and fibers that pass in front and loop below the artery (ansa subclavia)
inferior cervical ganglion
- fused to the first thoracic ganglion forming the stellate ganglion
- lies on neck of the first rib near the origin of the vertebral artery
- sends gray rami to VPR’s C7, 8
- sends white rami to VPR T1
- gives rise to thoracic visceral nerve to cardiac plexus
thyroid gland
- butterfly
- visceral neck
- 2 lobes connected by an isthmus just below the cricoid cartilage
- isthmus may demonstrate a pyramidal lobe extending cranially
thyroglossal duct
extension of pyramidal lobe with embryologic origin
-seen at foramen cecum at midline of tongue
parathyroid glands
- deeper surface of thyroid
- darker
- small bean size
anatomical differences between two sides of neck
- left recurrent laryngeal hooks about the aortic arch and arises in thorax and right around the right subclav
- right subclav and common carotid arise from brochiocephalic and on the left they arise from aortic arch
clinical correlations
- torticollis
- subclavian vein puncture
- corotid pulse and endarterectomy
- role of carotid sinus and body
- cricothyroidotomy and tracheostomy
- thyroglossal cyst
