Triangles of the neck Flashcards
palpable structures in the neck
hyoid bone, thyroid cartilage, cricoid cartilage, trachea
is the thyroid gland palpable?
no
Platysma O, I, N, A
O: undersurface of skin of lower neck + lateral chest
I: lower border of the mandible and kin of the lower face and angle of the mouth
N: CN VII - facial nerve
A: muscle of facial expression
Superficial muscles of the neck (3)
SCM, Trapezius, Platysma
SCM O, I, N, A
O: two heads on manubrium
I: lateral aspect of the mastoid process of the temporal bone
N: CN XI - accessory nerve
A: Turn head to OPPOSITE side
Trapezius innervation
CN XI - accessory nerve
3 deep fascias of the cervical region
- investing - most superficial, splits to encompass trapezius and SCM
- visceral - surrounds larynx, trachea, esophagus and thyroid gland
- prevertebral - forms collar around vertebral column and deep muscles assoc.
carotid sheath surrounds what 4 things?
fascial sheath around
- carotid artery
- internal jugular vein
- vagus nerve
- deep cervical lymph nodes
What action do the infrahyoid and supra hyoid muscles do together?
produce movements of larynx nec. for swallowing and speaking
Infrahyoid muscles (4)
- omohyoid
- sternohyoid
- sternothyroid
- thyrohyoid
suprahyoid muscles (4)
- anterior digastric
- posterior digastric
- stylohyoid
- mylohyoid
action of infrahyoid muscles
depress hyoid bone
action of suprahyoid muscles
elevate hyoid bone
Borders of anterior triangle
anterior border of SCM, inferior border of mandible, midline
4 triangles that are subdivisions of the anterior triangle
- submental
- submandibular
- carotid triangle
- muscular triangle
Submental triangle borders
anterior bellies of two digastric muscles, hyoid bone
submental triangle contents and floor
Contents: submental lymph nodes
Floor: mylohyoid muscles
submandibular triangle borders and floor
Borders: anterior and posterior bellies of digastric muscles, mandible
Floor: mylohyoid
Submandibular triangle contents (5)
- submandibular salivary gland and duct
- portions of facial vessels
- CN XII - hypoglossal nerve
- CN V - nerve to mylohyoid muscle
- lymph nodes
carotid triangle borders
superior belly of the omohyoid muscle, posterior belly of digastric, anterior border of SCM
Carotid triangle contents (5 in carotid sheath, 2 outside)
Encased by carotid sheath 1. common carotid artery + bifurcation 2. internal jugular vein 3. CN X - vagus nerve 4. carotid body and carotid sinus 5. deep cervical lymph nodes Outside of carotid sheath 1. portion of CN XII - hypoglossal nerve 2. portion of cervical plexus and ansa cervicalis
Right common carotid is the terminal branch of …
brachiocephalic trunk
Left common carotid originates from…
arch of the aorta
Branchpoint of common carotid arteries
at level of superior border of thyroid cartilage –> external and internal carotid arteries
what areas does the internal carotid artery supply?
no branches in neck, supplies brain, orbit, forehead
what areas does the external carotid artery supply?
upper neck, face and scalp w/ assoc. structures
branches of external carotid artery and what they supply: inferior –> superior (8)
- superior thyroid –> thyroid gland and larynx
- ascending pharyngeal –> pharynx
- lingual –> tongue
- facial –> submandibular gland, palatine tonsil, lower face
- occipital –> posterior scalp
- posterior auricular –> posterior to ear, supplies scalp
- maxillary –> infratemporal and pterygopalatine fossa, nasal cavity and palate
- superficial temporal –> anterior to ear, supplies scalp
Where is the carotid sinus located and what does it sense?
Location: dilation of proximal ICA
Function: baroreceptor sensitive to BP
Where is the carotid body located and what does it sense?
Location: crotch b/t ICA and ECA
Function: senses PO2 and PCO2
Where do the afferents from carotid sinus and body travel?
CN IX - glossopharyngeal nerve
Major veins of neck (2)
- IJV
2. EJV
course of EJV
descends superficial to SCM, empties into subclavian vein
course of IJV
descends from skull w/in carotid sheath, converges w/ subclavian to form brachiocephalic vein
phrenic nerve course through neck
descends along anterior surface on anterior scalene muscle deep to prevertebral fascia and SCM
muscular triangle borders
hyoid bone, superior belly of omohyoid muscle, anterior border of SCM, midline
Contents of muscular triangle
4 infrahyoid/strap muscles
- omohyoid
- sternohyoid
- sternothyroid
- thyrohyoid
innervations of strap muscles
- omohyoid, sternohyoid, sternothyroid = ansa cervicalis of cervical plexus
- thyrohyoid = nerve fibers from C1
posterior triangle borders, roof, floor
Borders: posterior border of SCM anteriorly, anterior border of trapezius posteriorly, mid-clavicle inferiorly
Roof: cervical investing fascia
Floor: prevertebral fascia
what artery can be palpated in most inferior aspect of posterior triangle?
third portion of subclavian
muscles deep to floor of posterior triangle (superior –> inferior)
splenius capitis, levator scapulae, posterior, middle, anterior scalenes, transverse to inferior belly of omohyoid
Contents of posterior triangle - vessels
- third portion of subclavian artery + its branches
- subclavian vein and EJV
- transverse cervical and suprascapular arteries
Contents of posterior triangle - nerves (3)
- accessory nerve
- some branches of cervical plexus
- roots/trunks of the brachial plexus
cervical plexus formed by …
ventral rami C1-C4
what area/muscles does the cervical plexus supply?
- neck muscles and diaphragm (via phrenic)
- area of skin on head, neck, chest
what muscles are innervated by ansa cervicalis
sternohyoid, sternothyroid, omohyoid
superficial nerves of cervical plexus (4)
Emerging from one location on posterior aspect of SCM: 1. transverse cervical 2. supraclavicular 3. great auricular From different spot: 4. lesser occipital
lymph drainage from neck
superficial cervical lymph nodes w/ EJV –> deep cervical lymph nodes w/ IJV
