HS2-2 Posterior Triangle Flashcards
What are the three compartments of the neck?
somatic neck
visceral neck
carotid sheath
Describe the composition of the somatic neck. (2)
vertebral column
muscles of posterior neck associated with vertebrae
Describe the composition of the visceral neck.
includes structures associated with feeding and respiration
What is another name for the visceral neck?
“gut neck”
Draw out a hierarchical diagram of the fasciae of the neck.
Describe superficial cervical fascia.
fatty connective tissue b/w dermis of skin and investing layer of deep cervical fascia
What is platysma?
broad thin sheet of muscle in subcutaneous cervical tissue of neck
What is the source of innervation for platysma?
facial nerve (CN VII)
What is the function of platysma?
tenses skin and muscles of facial expression
What are the contents of the carotid sheath? (4)
common carotid artery
internal carotid artery
internal jugular vein
vagus nerve
Where is the retropharyngeal space located?
between peritracheal and perivertebral layers of fascia
List the structures that comprise the skeleton/bones of the neck.
C1 (atlas)
C2 (axis)
C3-C6
C7 (a.k.a. vertebra prominens)
hyoid bone (which does not directly articulate with other bones)
List the structures that comprise the musculature of the neck.
sternocleidomastoid
trapezius
suprahyoid
infrahyoid
scalenes (anterior/middle/posterior)
What is the function of the sternocleidomastoid?
connects the head to upper extremities
Which muscle is the largest muscle producing head movement?
sternocleidomastoid
Describe how the sternocleidomastoid and trapezius contribute to the posterior triangle.
Sternocleidomastoid forms anterior boundary of posterior triangle
trapezius forms posterior boundary of posterior triangle
What innervates the sternocleidomastoid?
accessory nerve (CN XI)
Describe the movements associated with the trapezius.
extension of neck and head
Describe the movements associated with the sternocleidomastoid. (2)
if contracted unilaterally = head turns contralaterally while raising chin
if contracted bilaterally = flexion of neck and extension of head
Where are the supra- and infrahyoid muscles located?
anterior triangle
What is the function of the suprahyoid and infrahyoid muscles?
move the hyoid bone, larynx, and lower jaw
What is the source of innervation of the scalene muscles?
innervated by ventral primary rami of cervical spinal nerves
What is the function of the scalene muscles? (2)
flex neck anteriorly and laterally
assist in respiration
Order the musculature of the neck, from superficial to deep.
sternocleidomastoid/trapezius (superficial)
suprahyoid/infrahyoid
scalenes (anterior/middle/posterior)
What groups comprise the visceral structures?
endocrine group = thyroid and parathyroid glands
respiratory group = larynx and trachea
alimentary group = pharynx and esophagus
List the arterial structures associated with the neck.
common carotid artery
subclavian artery
Describe how the common carotid and subclavian arteries branch. (3)
common carotid → internal + external
subclavian → vertebral + thyrocervical trunk
thyrocervical trunk → suprascapular + transverse cervical + inferior thyroid
Describe the branching of the internal carotid artery.
no branches in the neck
What does the internal carotid artery supply? (2)
brain
eye
Describe the branching of the external carotid artery.
has many branches in the neck
What does the external carotid artery supply?
supplies neck and head structures
What does the subclavian artery supply? (2)
supplies UEs + neck
Describe the branching of the vertebral artery.
no major branches in neck
What does the vertebral artery supply? (2)
supplies brain + spinal cord
What are the three major branches of the thyrocervical trunk?
suprascapular artery
transverse cervical artery
inferior thyroid artery
What does the suprascapular artery supply?
supplies shoulder region
What does the transverse cervical artery supply?
supplies superficial back
What does the inferior thyroid artery supply?
supplies thyroid gland
What are the three primary venous structures associated with the neck?
internal jugular vein
external jugular vein
subclavian vein
Describe the relationship between the internal jugular vein and the brain.
the internal jugular vein is the only source of drainage for the brain
What is the primary venous structure of the neck?
internal jugular vein
Describe the relationship between the internal jugular vein and the subclavian vein.
internal jugular vein joins with subclavian vein to form braciocephalic vein
Describe the function of the external jugular vein.
drains most of scalp and side of face
What is the ultimate fate of the external jugular vein?
empties into subclavian vein
Explain the relationship between the subclavian vein and the axillary vein.
subclavian vein is the continuation of the axillary vein from the upper extremity
What are the three types of nerves found in the neck?
cranial nerves
sympathetic neural structures
cervical spinal nerves
What are the three cranial nerves that extend into the neck?
vagus nerve (CN X)
accessory nerve (CN XI)
hypoglossal nerve (CN XII)
What functions do the cranial nerves found in the neck have? (3)
motor
sensory
parasympathetic
How is the vagus nerve unique among the cranial nerves found in the neck?
it’s the only cranial nerve that runs completely through the neck
How does the vagus nerve exit the skull?
via jugular foramen, then runs in carotid sheath
Describe the parasympathetic, motor, and sensory functions of the vagus nerve.
parasympathetic = viscera of thorax and abdomen
motor = pharynx and larynx
sensory = pharynx and larynx
How does the accessory nerve exit the skull?
through jugular foramen
Describe the function of the accessory nerve.
motor innervation to trapezius and sternocleidomastoid
How does the hypoglossal nerve exit the skull?
through hypoglossal canal
Describe the function of the hypoglossal nerve.
motor innervation to muscles of tongue
Describe the contributions of the cervical spinal nerves.
lower four = form brachial plexus
upper four = form cervical plexus
What structures form the boundary of the root of the neck?
first rib
manubrium
T1 vertebra
Which muscles found in the root of the neck contribute to the head and neck? (3)
prevertebral muscles (including scalenes)
scalene muscles
infrahyoid muscles
Apart from muscles, innervation, and vasculature, what specific structures found in the root of the neck make contributions to the head and neck? (3)
cervical vertebrae
trachea
esophagus
Which bones in the root of the neck make contributions to the upper extremity? (2)
clavicle (sometimes not considered to be in the root of the neck)
manubrium
Which vessels in the root of the neck make contributions to the upper extremity? (3, +2, +0, +2)
-
transverse cervical artery, which yields:
- superficial cervical artery
- dorsal scapular artery (30% of the time)
- suprascapular artery
-
from thyrocervical trunk, which yields:
- dorsal scapular artery (70% of the time)
- subclavian artery
What are the boundaries of the interscalene triangle? (2)
anterior and middle scalenes
first rib
What are the contents of the interscalene triangle? (2)
brachial plexus
subclavian artery
What blood vessel is located outside but is still associated with the interscalene triangle?
subclavian vein
Apart from vasculature, which specific structures make contributions to the upper extremity? (4)
clavicle
manubrium
roots of brachial plexus
interscalene triangle
Which bones make contributions to the thorax? (2)
first rib
manubrium
Which visceral structures make contributions to the thorax? (5)
cupula
cervical pleura
thoracic duct
esophagus
trachea
Which vessels make contributions to the thorax? (4)
internal thoracic artery
brachiocephalic trunk
right/left brachiocephalic veins
internal thoracic vein
Which nerves make contributions to the thorax? (4)
phrenic nerve (C3/C4/C5)
vagus nerve
cervical sympathetic chain (middle cervical ganglion + stellate ganglion)
In the context of innervation to the thorax, where is the phrenic nerve found?
on anterior aspect of anterior scalene
In the context of innervation to the thorax, where is the stellate ganglion found?
deep to first rib
What are the boundaries of the posterior triangle?
clavicle (inferior border)
sternocleidomastoid (anterior border)
trapezius (posterior border)
What structure separates the posterior and anterior triangles?
sternocleidomastoid
What forms the roof of the posterior triangle?
investing layer of deep cervical fascia
What forms the floor of the posterior triangle? (3)
perivertebral fascia covering middle + posterior scalenes
splenius capitis
levator scapulae
Describe the relationship between the omohyoid muscle and the posterior triangle.
inferior belly of omohyoid runs across lower portion of triangle, separating the triangle into:
omoclavicular triangle (small, inferior)
occipital triangle (large, superior)
Describe the relationship between the spinal accessory nerve and the posterior triangle.
spinal accessory nerve divides triangle into “careful” vs. “carefree” zones
What are the three main nerves/nervous structures found in the posterior triangle?
spinal accessory nerve (CN X)
cervical plexus
brachial plexus
Describe the function of the spinal accessory nerve in the posterior triangle.
motor innervation to trapezius and sternocleidomastoid
Describe the branching of the cervical plexus in the posterior triangle and the associated functions.
sensory:
great auricular nerve = sensory to region around ear
lesser occipital nerve = sensory to scalp
transverse cervical (colli) nerves = sensory to anterior triangle
supraclavicular nerve = sensory to posterior triangle
motor:
phrenic nerve = motor to diaphragm
What nerve provides sensory innervation to the area around the ear?
great auricular nerve
What nerve provides sensory innervation to the scalp?
lesser occipital nerve
What nerve provides sensory innervation to the anterior triangle?
transverse cervical (colli) nerves
What nerve provides sensory innervation to the posterior triangle?
supraclavicular nerves
What nerve provides motor innervation to the diaphragm?
phrenic nerve
Describe the branching of the brachial plexus in the posterior triangle. (2)
ventral primary rami of C5-T1 give rise to roots and trunks
dorsal scapular nerve from brachial plexus root innervates rhomboids and levator scapulae
What is the primary venous structure associated with the posterior triangle?
external jugular vein = drains most of scalp and side of face
What are the three primary arteries associated with the posterior triangle?
transverse cervical artery
suprascapular artery
dorsal scapular artery
In the context of the posterior triangle, what is the function of the transverse cervical artery?
supplies superficial muscles of back (via superficial cervical artery)
in 30% of cases, supplies rhomboids + levator scapulae via dorsal scapular artery
In the context of the posterior triangle, what is the function of the suprascapular artery?
supplies muscles of shoulder region (i.e. supraspinatus and infraspinatus)
The dorsal scapular nerve is contained in which triangle?
posterior triangle
Describe the relationship between the brachial plexus and the scalene muscles.
brachial plexus runs between anterior and middle scalenes
Describe the relationship between the phrenic nerve and the scalene muscles.
phrenic nerve runs on top of anterior scalene
What causes thoracic outlet syndrome?
compression of the contents of the interscalene triangle
What is the function of the infrahyoid muscles?
stabilize hyoid
depress hyoid when swallowing
What is another name for the infrahyoid muscles?
strap muscles
Describe the relationship of the sternothyroid, sternohyoid, and thyrohyoid.
sternohyoid is superficial to both the sternothyroid and thyrohyoid
Draw out a simplified cervical plexus.
Describe the branching of the subclavian artery.
left subclavian branches off aortic arch
right subclavian branches off brachiocephalic artery
What are the branches of the subclavian artery?
Very Important TITS D-Size
vertebral
internal thoracic
thyrocervical trunk
inferior thyroid
transverse cervical
suprascapular
dorsal scapular
What are the nerves of the cervical plexus?
GLAST:
great auricular
lesser occipital
accessory
supraclavicular
transverse cervical
