Brachial Plexus 5

Question 0

What happens to the dorsal rami of the spinal nn?

Answer 0

They stay segmented to innervate the back

Question 1

The ______ rami is responsible for the formation of a plexus

Answer 1

Ventral rami

Question 2

Name 3/4 plexuses that arise from the spinal cord and their root values

Answer 2

Cervical, C1-4
brachial, C5-T1
lumbosacral L2-S5

Question 3

Where are the roots, trunks, divisions, cords, terminal branches?

Answer 3

Roots: prevertebral musculature 
Trunks: posterior triangle
Divisions: behind clavicle
Cords: in axilla 
Branches: throughout the upper limb

Question 4

What are the 3 trunks of the brachial plexus? What forms them?

Answer 4

Superior/Upper: C5-6
middle: C7
inferior/lower: C8-T1

Question 5

How do the trunks get their names?

Answer 5

Their relationship to one another.

Question 6

Where do the trunks terminate?

Answer 6

Behind the clavicle and they become the divisions

Question 7

How are the cords formed?

Answer 7

All 3 posterior divisions form the posterior cord. The lateral cord is formed from from the upper two anterior portions. The medial cord is formed from the lower anterior division.

Question 8

How are the cords named?

Answer 8

For the anatomical relationship to the axillary artery

Question 9

List the branches off the roots of the brachial plexus and what do they innervate?

Answer 9

Dorsal scapular n (C5): levator, rhomboids

Long thoracic n (C5-7): anterior serratus m

Question 10

Which trunk exhibits branches? What are the nn and what do they innervate?

Answer 10

Superior trunk
Nerve to subclavius (C5-6): subclavius
Suprascapular (C5-6): supraspinatus, infraspinatus

Question 11

What are the 3 branches from the lateral cord and what spinal cord segments do they arise from?

Answer 11

Lateral pectoral n (C5-7)
*Musculocutaneous (C5-7)
Lateral root of the median n (C6-7)

Question 12

What do the branches of the lateral cord innervate?

Answer 12

Lateral pectoral n: pectoralis major
Musculocutaneous: muscles in anterior compartment (flexors)
Lateral root of the median n: median n (most flexors of forearm)

Question 14

The branches of the posterior cord innervate what muscles?

Answer 14

Upper subscapular n: subscapularis
Thoracodorsal n : latissimus dorsi
Lower subscapular n: subscapularis and teres major
Axillary n: deltoid and teres minor
Radial n: triceps brachii and anconeus (extensors) and posterior compartment

Question 15

Name the branches of the posterior cord and what spinal cord segments they arise from.

Answer 15

Lower and upper subscapular: C5-6
Thoracodorsal: C6-8
*Axillary: C5-6
*Radial: C5-T1 ALL

Question 16

Name the branches of the medial cord and their root values

Answer 16

Medial pectoral n: C8-T1
Med cutaneous n of the arm: T1
Med cutaneous n of forearm: C8-T1
Medial root of median n
Ulnar n: C8-T1

Question 17

What do the branches of the medial cord innervate?

Answer 17

Medial pectoral n: pectoralis major and minor
Med cutaneous n of arm/forearm: sensory branch (no mm innervation)
Medial root of median n: median n
Ulnar n: skin and mm of forearm and hand

Question 18

What three nn form the M over the surface of the axillary artery?

Answer 18

Musculocutaneous
Lateral root of median n
Median root of median n
Ulnar n

Question 19

What is the relationship of the axillary vein to the axillary artery?

Answer 19

The axillary vein is superficial to the artery

Question 20

What is the relationship of the median nerve to the axillary artery?

Answer 20

The nerve is anterior to the artery

Question 21

What is the relationship of the radial n to the axillary artery?

Answer 21

Axillary artery is superficial to the radial nerve