Posterior Triangle and Root of Brachial Plexus

Question 1

What can be found in the posterior triangle?

Answer 1

Two major plexuses of nerves: Cervical plexus and brachial plexus

Question 2

What is the course of the common cartoid artery?

Where does it bifurcate?

Answer 2

Starts from chest and projects upward, accompained by the internal jugular vein.

It splits around C4 into the internal carotid (posterior) and the external carotid (anterior)

Question 3

What is the main cutaneous branch of the cervical plexus?

Answer 3

Supraclavicular nerves (C3/C4)

Question 4

Where does the supraclavicular nerve go?

Answer 4

It has medial, intermediate, and lateral branches to areas adjacent to the clavicle

Question 5

Describe the phrenic nerve

Answer 5

(C3,C4,C5) It innervates the diaphragm

Question 6

What is the course of the phrenic nerve?

Answer 6

Courses on the anterior surface of the anterior scalene muscle before entering the mediastinum.

Question 7

What are the boundaries of the thoracic inlet (superior thoracic aperture)

Answer 7

Body of T1 vertebra

1st rib

Manubrium

Medial end of the clavicle intrudes into this space

Question 8

What structures pass through the thoracic inlet (superior thoracic aperture)

Answer 8

Longus colli

Scalene muscles

Common carotid artery/internal jugular vein

Vagus nerve

Phrenic nerve

Esophagus

Trachea

Infrahyoid muscles

Apex of lung

Question 9

What is the thoracic outlet?

Answer 9

It is a small subdivision of the inlet where nerves and vessels are squeezed between the clavicle above and the first rib below

Question 10

What are the branches of the subclavian artery?

Answer 10

Internal thoracic artery

Thryocervical trunk

Costocervical artery

Dorsal scapular artery

Question 11

What are some of the variations in the subclavian artery?

Answer 11

The Transverse cervical artery, suprascapular artery, and dorsal scapular artery may have partly fused origins

Question 12

What is Thoracic Outlet Syndrome?

Answer 12

A condition where the subclavian artery can become compressed

Question 13

What is the function of the vagus nerve?

Answer 13

Main postcrainal parasympathetic autonomic nerve

Carries visceral sensory nerve axons from heart, lungs, and guts

Question 14

What nerves can be found in the posterior triangle?

Answer 14

Phrenic nerve

Vagus nerve

Cervical plexus (C1-C4 rami)

Roots of the brachial plexus (ventral rami of C5-T1)

Question 15

Arteries located in the posterior triangle

Answer 15

Ascending cervical artery

Transverse cervical artery

Question 16

Veins located in the posterior triangle

Answer 16

Internal jugular vein

Question 17

From medial to lateral, what is the order of the significant veins, arteries, and nerves in the posterior triangle?

Answer 17

Common cartoid artery

Vagus nerve

Internal jugular vein

Phrenic nerve

Question 18

What is torticullis?

Answer 18

A clinical condition caused by unilateral shortening or contraction of one sternocleidomastoid muscle

Question 19

What forms Erb’s point?

Answer 19

The union of the C5 and C6 nerve roots

Question 20

What is Erb’s palsy?

Answer 20

A condition where the C5 and C6 nerve roots are damaged (usually caused by a drop on the shoulder)