Posterior Triangle 3 Flashcards Preview

Anatomy Test 1 > Posterior Triangle 3 > Flashcards

Flashcards in Posterior Triangle 3 Deck (21):

What is the key muscle of the neck? What is is attached to? What does it do? What it's innervation?

The sternocleidomastoid.
It's attached to the mastoid process, sternum and clavicle.
It functions to tilt the head toward the shoulder of the same side and rotate the face to the opposite side. Together, both muscles protract (or draw forward) the head.
It's innervated by the Cranial nerve XI.


What does the SCM divide the neck into?

Posterior and anterior triangles


What are the 3 "compartments" that make up the neck?

1. Posterior: support-vertebral column, musculature for flexion/extension of neck
2. Anterior or median visceral: 2 anterior triangles, deep viscera (larynx/trachea and pharynx, and a neurovascular bundle
3. Posterior triangles (lateral cervicle regions): continuous with axilla, brachial plexus and subclavian a/v are here


What are the 4 layers of cervical fascia?

1. Investing layer: roofs the posterior and anterior triangles, surrounds the entire neck
2. Pretracheal: forms sheath around thyroid
3. Prevertebral: forms fascial carpet over floor of post. triangle, surrounds support compartment (musc./vert.)
4. Carotid sheath: condensation of all 3 layers enclosing the verticle neurovascular bundle (common carotid a., internal jugular v., vagus n.)


What are the boundaries of the posterior triangle?

Base: superior border of the clavicle
Anterior: posterior border of the SCM
Posterior: anterior border of trapezius
Roof: investing layer of cervical fascia
Floor: musculature and prevertebral fascia


Which muscles divides the posterior triangle into 2 subtriangles? What are these triangles?

The inferior belly of omohyoid
1) occipital triangle: larger and superior
2) supraclavicular triangle : smaller and inferior


Name an important structure in the supraclavicular triangle.

The subclavian artery


The ventral rami of _________ plexus and _________ plexus can be found in the posterior triangle.

Cervical and brachial


Where are the brachial and cervical plexus located? (What spinal cord levels?)

Cervical: C1-C4
Brachial: C5-C8/T1


Which plexus is purely sensory?



Where is the brachial plexus located? What does it supply?

Floor of the triangle between the scalenus anterior and medius. It supplies sensory innervation for the upper limb.


What does the cervical plexus supply innervation to? What are the 4 major nerves that make up this plexus? Which nerve can we see in lab?

It supplies sensory innervation to the neck and upper thorax.
1. Lesser occipital
2. Transverse cutaneous
3. Great auricular
4. Supraclavicular <~~~~


Which 3 nerves/plexuses can be found in the post triangle?

Brachial plexus
Cervical plexus
Accessory nerve


Where is the needle inserted in a cervical block?

1/2 way up the posterior border of the SCM


Where is the accessory nerve found? What does it supply?

Crosses overtop of the levator scapulae
It supplies motor information to the SCM and trapezius.


Name the muscles that make up the floor of the posterior triangle.

Scalenus anterior
Scalenus medius
Levator scapulae
Selenium capitis
Semispinalis capitis


Where does the phrenic nerve lie?

Crosses overtop the anterior scalene


Where does the brachial plexus enter the axilla?

Cervicoaxillary canal


Where do the scalene muscles arise from on the vertebrae? Insertion?

Transverse processes of cervical nerves
R1 and R2


The accessory nerve lies _______ the fascial carpet.



What are the functions of the SCM?

Unilaterally acts to tilt the head to the same side and rotate the head to the opposite side.
Bilaterally acts to extend the head and to aid in respiration when the head is fixed.