Posterior Triangle

Question 1

What are the Fascial Layers of the Neck

Answer 1

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

Question 2

What are the borders of the posterior triangle?

Answer 2

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

Question 3

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

Answer 3

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.

Question 4

What is present in the Occipital Triangle?

Answer 4

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

Question 5

What is the ERB’s point

Answer 5

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

Question 6

What nerve innervates the SCM muscle

Answer 6

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

Question 7

What is the action of the SCM muscle

Answer 7

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

Question 8

What are the muscles of the neck?

Answer 8

SCM, Trapezius and Scalene muscles

Question 9

Scalene Muscles

Answer 9

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

Question 10

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

Answer 10

The middle scalene

Question 11

What are the motor branches of the cervical plexus.

Answer 11

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
   Sternohyoid
   Sternothyroid
   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)

Question 12

What is a landmark for the phrenic nerve?

Answer 12

It lies right on top of the anterior scalene

Question 13

What is a landmark for the ansa cervicalis?

Answer 13

It lies superficial to the internal jugular vein.

Question 14

What is a landmark for the Subclavian vein?

Answer 14

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

Question 15

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

Answer 15

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

Question 16

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

Answer 16

They both run in front of the anterior scalene.

Question 17

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

Answer 17

It runs behind deep to the anterior scalene

Question 18

What can you find in the supraclavicular triangle?

Answer 18

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.

Question 19

Subclavian Artery Branches

Answer 19

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)

Question 20

Where do the roots of the brachial plexus lie

Answer 20

between the anterior and middle scalene muscles