Brachial Plexus

Question 1

Nerve Roots

Answer 1

C5, C6, C7, C8, T1

Question 2

Trunks

Answer 2

Upper (C5 and C6)
Middle (C7)
Lower (C8 and T1)

Question 3

Divisions

Answer 3

Posterior (all roots and all trunks)
Anterior (upper and middle trunks form and lower trunk forms this division)

Question 4

Cords

Answer 4

Lateral (anterior division)
Medial (anterior division)
Posterior (posterior division)

Question 5

Branches

Answer 5

Musculocutaneous (formed by lateral cord)
Median (lateral and medial cord)
Radial (posterior cord)
Axillary (posterior cord)
Ulnar (medial cord)

Question 6

What does the musculocutaneous nerve innervate? (BBC)

Answer 6

The Anterior Arm (BBC)
- Biceps Brachii
- Brachialis
- Coracobrachialis

Question 7

What does the radial nerve innervate?

Answer 7

• Triceps Brachii
• Extensors in forearm
• Skin in forearm, hand and 3 and 1/2 fingers

Question 8

What does the axillary nerve innervate?

Answer 8

• Deltoid
• Teres Minor
• Triceps Brachii (Lateral Head)
• Glenohumeral

Question 9

What would an injury to the axillary nerve cause?

Answer 9

• Weakness in abduction
• Paralysis of deltoid and teres minor
• Wasting of deltoid
• Loss of sensation to deltoid

Question 10

What does the median nerve innervate?

Answer 10

• Forearm flexor muscles
• Lumbricals
• Thenar Muscles
• Skin in the hand

Question 11

What would an injury to the median nerve cause?

Answer 11

• Pain and numbness in 3 and 1/2 fingers
• Pain and numbness when flexing wrist
• Thenar muscle weakness
• Damage to lumbricals = difficult to flex metacarpophalangeal and interphalangeal joints in 2nd and 3rd fingers

Question 12

What does the ulnar nerve supply?

Answer 12

• Flexor carpi ulnaris
• Flexor digitorum profundus
• Intrinsic muscles except LOAF

Question 13

What would an injury to the ulnar muscle cause?

Answer 13

Difficulty extending metacarpophalangeal joints and flexion of interphalangeal joints of 4th and 5th fingers

Question 14

Mnemonic to remember injuries to nerves in the hand and how it presents.

Answer 14

DR. CUMA

Drop = Radial
Claw = Ulnar
Median = Ape

Question 15

What are types of brachial plexus injuries?

Answer 15

Neuropraxia
Brachial Plexus rupture
Brachial Plexus Avulsion

Question 16

What are two types of neuropraxia?

Answer 16

compression - nerve root is compressed
traction - when a nerve root is pulled down

Question 17

What is neuropraxia?

Answer 17

when nerves are stretched too much

Question 18

What is a brachial plexus rupture?

Answer 18

when a stretch causes the nerve to tear
sometimes causing muscles to be no longer usable.

Question 19

What is a brachial plexus avulsion?

Answer 19

The nerve root completely separates from the spinal cord, often causing permanent weakness, paralysis and loss of feeling.