1.1.2. Nerve Supply to the Upper Limb

Question 1

What is the name given to the major network of nerves which innervate the upper limb?

Answer 1

The Brachial Plexus

Question 2

Where can the Brachial Plexus be found?

Answer 2

1. It begins at the Cervical Region

2, It extends to the Axilla

Question 3

1. What Rami forms the Brachial Plexus?

2. What Spinal Levels do these Rami come from?

Answer 3

1. Ventral Rami

2. C5, C6, C7, C8, and T1

Question 4

What nerve roots form the Upper Trunk?

Answer 4

1. C5

2. C6

Question 5

What is Erb’s Point?

Answer 5

The point where C5 and C6 converge to form the Upper Trunk

Question 6

1. What does injury to the Upper Trunk cause?
2. How will this present?
3. What can cause this?

Answer 6

1. Erb’s Palsy - Paralysis of the Biceps Brachii, Brachialis, Corticobrachialis, and Brachioradialis
2. “Waiters Tip” appearance (medially rotated with wrist flexed)
3. a) Shoulder Dystocia at birth
4. b) A Fall onto the shoulder

Question 7

What Acronym can be used to remember the order of Brachial Plexus stages?

Answer 7

Read   - Roots
That    - Trunks
Damn - Divisions
Card   - Cords
Back   - (Terminal) Branches

Question 8

What nerve roots form the Lower Trunk?

Answer 8

1. C8

2. T1

Question 9

1. What does injury to the Lower Trunk cause?

2. What can cause this?

Answer 9

1. Klumpke’s Palsy - Paralysis of the Intrinsic Muscles of the Hand, and Ulnar Flexors of the Wrist and Fingers
2. Undue abduction of the arm

Question 10

1. What do the division of the 3 trunks form?
2. How many divisions do the trunks divide into?
3. Where can this be found?

Answer 10

1. Cords (Read That Damn Card Back
2. 2, Each trunk has an Anterior and a Posterior Division
3. In the Axilla

Question 11

What are the names of the Cords formed in the Axilla?

Answer 11

1. Lateral Cord
2. Posterior Cord
3. Medial Cord

Question 12

How are the Cords of the Brachial Plexus named?

Answer 12

After their position in relation to the Axillary Artery in the Axilla

Question 13

What root(s) form the:

a) Upper Trunk
b) Middle Trunk
c) Lower Trunk

Answer 13

The ventral rami of:

a) C5 and C6
b) C7
c) C8 and T1

Question 14

What are the branches of the Lateral Cord of the Brachial Plexus?

Answer 14

1. Lateral Pectoral (C5, 6, 7)
2. Lateral Root of the Median Nerve (C5, 6, 7, 8, T1)
3. Musculocutaneous Nerve (C5, 6, 7)

Question 15

What are the branches of the Medial Cord of the Brachial Plexus?

Answer 15

1. Medial Pectoral (C8, T1)
2. Ulnar Nerve (C7*, 8, T1)
3. Medial Root of the Median Nerve (C5*, 6, 7, 8, T1)
4. Medial Cutaneous Nerve of the Arm (T1)
5. Medial Cutaneous Nerve of the Forearm (C8)

Question 16

What are the branches of the Posterior Cord of the Brachial Plexus?

Answer 16

1. Thoracodorsal Nerve (C6*, 7, 8)
2. Axillary Nerve (C5, 6)
3. Radial Nerve (C5, 6, 7, 8, T1*)
4. Upper and Lower Subscapular Nerve (C5 ,6)

• = inconsistent contribution

Question 17

What nerve is formed from the roots of C5, C6, and C7?

Answer 17

The Long Thoracic Nerve