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Flashcards in Posterior Triangle Deck (20):

What are the Fascial Layers of the Neck

1. Investing Layer of dense connective tissue- binds all structures in the neck. It is attached to the lagamentum nuchae and the spinous process of C7. It also splits so that it can individual enclose the SCM muscle and the Trapezius muscle

2. Infrahyoid fascia- It cover the supra and infrahyoid muscles. supra=digastric, stylohyoid, geniohyoid, ad mylohyoid. Infra= sternohyoid, sternothryoid, thyrohyoid, and omohyoid.

3. Pretracheal fascia- It includes structures that are close to the trachea: trachea, larynx, thyroid glad, parathyroid gland, and esophagus.

4. Coratid Sheath- encloses an artery, a vein, and a nerve. The coratid artery, the internal jugular vein and the vagus nerve.(involuntary nervous system like constant heart rate)

5. Prevertebral fascia- covering vertebral musculature


What are the borders of the posterior triangle?

Anterior: SCM muscle
Posterior: Trapezius muscle
Inferior: Clavicle bone


What muscle comes in at a 45degree angle and divides the posterior triangle? What are the two new triangles?

Inferior belly of hte Omohyoid muscle.

1. Occipital Triangle is above the omohyoid( you can see the brachial plexus
2. Supraclavicular Triangle is below the omohyoid.


What is present in the Occipital Triangle?

Cervical plexus cutaneous branches
Cranial nerve #11 (Accessory nerve)
Phrenic nerve
Trasnverse Cervical ARTERY


What is the ERB's point

Erbs point is an area where all of the cutaneous branches of the cervical plexus emerge. (sensory)

1. Greater Auricular N. (auricular means ear) C2-C3
2. Lesser Occipital N. C2 and sometimes C3
3. Transverse Cervical(anteriorly) N. C2-C3
4. Supraclavicular N. C3-C4


What nerve innervates the SCM muscle

Cranial nerve 11. The same nerve that innervates the trapezius muscle


What is the action of the SCM muscle

Laterally flexes the neck and rotates the head to the opposite side.


What are the muscles of the neck?

SCM, Trapezius and Scalene muscles


Scalene Muscles

All scalene muscles laterally flex the neck and are used for forced inspiration. However, the anterior scalene muscle also anteriorly flexes the neck.

The anterior and middle scaled elevate the first rib and the posterior scalene elevates the second rib.

They are also all innervated by an anterior primary rami of different cervical vertebrae


Which scalene muscle is the longest and the largest scalene muscle?

The middle scalene


What are the motor branches of the cervical plexus.

1. Geniohyoid
2. Thyrohoid
3. Ansa cervicalis -Note: there is a superior root and an inferior root. The superior root is from C1 and is called the descendens hypoglossi and the inferior root is from C2 and C3. It is called the descendens cervicalis
Omohyoid Superior
Omohyoid Inferior
4. Phrenic Neve
5. Ventral Rami - to the rectus capitis laterallis, rectus capitas anterior, longus capitas, longus colli, levator scapulae and scalene muscles

mneumonic: 1,2,3 ansa cervacalis me. 3,4,5 keeps the diaphragm alive(phrenic)


What is a landmark for the phrenic nerve?

It lies right on top of the anterior scalene


What is a landmark for the ansa cervicalis?

It lies superficial to the internal jugular vein.


What is a landmark for the Subclavian vein?

It runs behind the clavicle and in front of the anterior scalene


What is a landmark for the Subclavian artery AND brachial plexus?

It runs between the anterior and the middle scalene (behind the anterior scalene)


What is a landmark for the transverse cervical artery AND the suprascapular artery?

They both run in front of the anterior scalene.


What is a landmark for the Dorsal scapular artery if it exist?

It runs behind deep to the anterior scalene


What can you find in the supraclavicular triangle?

1. Lower portion of the brachial plexus
2. Subclavian artery and vein
3. Branches of the subclavian artery (VITamin C and sometimes D)
4. Termination of external jugular vein.


Subclavian Artery Branches

Reference is our anterior scalene muscle.
First Portion:
1. Vertebral Artery
2. Internal Thoracic Artery
3. Thyrocervical Trunk (IAT'S [almost like it's but you have an A])
I- Inferior thyroid artery
A - Ascending cervical artery
T- Transverse cervical artery
S- Suprascapular artery

Second Portion:
1. Costocervical Trunk
Supreme intrcostal artery.
Deep cervical artery

Third Portion:
1. Dorsal Scapular artery ( not always present)


Where do the roots of the brachial plexus lie

between the anterior and middle scalene muscles