Lecture 20 - Neuroanatomy & Brachial Plexus

Question 1

What are nerve roots?

Answer 1

• Paired branches that leave the spinal cord at each vertebral segment
• Exit spinal column through the intervertebral foramen
• Mixed nerves comprised of both:

      - Efferent (motor) fibres
      - Afferent (sensory) fibres

Question 2

What is the brachial plexus?

Answer 2

• Plexus = network of nerves or vessels in the body that have a web-like formation
• Formed by anterior rami of nerve roots C4 - T1

Question 3

How many terminal nerves are in the brachial plexus? What are they?

Answer 3

• 5 total
• Musculotaneous
• axillary
• radial
• median
• ulnar

Question 4

What is the Musculotaneous nerve?

Answer 4

• C5, C6 & C7
• Innervation muscles of the anterior brachium
• i.e., Biceps Brachii, Brachialis, Coracobrachialis

Question 5

What is the axillary nerve?

Answer 5

• C5 & C6
• Innervation of the deltoid & teres minor

Question 6

What is the radial nerve?

Answer 6

• C5, C6, C7, C8
• Innervation of the Triceps, Brachioradialis, & muscles of posterior forearm

Question 7

What is the median nerve?

Answer 7

• C6 , C7, C8 & T1
• innervates Most muscles of the anterior forearm
  I.e., Pronator Teres, Palmaris Longus, Flexor Carpi Radialis, Flexor Digitorum Profundus/ Superficialis
• innovates Muscles of the hand
  - Lumbricals (1 & 2), Thenar group

Question 8

What is the ulnar nerve?

Answer 8

• C7, C8 & T1
• Medial Muscles of the Forearm
• i.e., Flexor Carpi Ulnaris, Flexor Digitorum Profundus (medial half), Hypothenar group, Lumbricals (3 & 4), Interossei (dorsal & palmar)

Question 9

How many peripheral nerves are in the brachial plexus? What are they?

Answer 9

• 9 total
• long thoracic nerve, dorsal scapular nerve, nerve to subclavius, suprascapular nerve, lateral/medial pectoral nerve, upper/lower subscapular nerve, thoracodorsal nerve

Question 10

What is the long thoracic nerve?

Answer 10

• C5, C6 & C7)
• i.e., Serratus Anterior

Question 11

What is the long thoracic nerve?

Answer 11

• C5, C6 & C7)
• i.e., Serratus Anterior

Question 12

What is the dorsal scapular nerve?

Answer 12

• C4 & C5
• i.e., rhomboids & levator scapulae

Question 13

What is the dorsal scapular nerve?

Answer 13

• C4 & C5
• i.e., rhomboids & levator scapulae

Question 14

What is the nerve to subclavius?

Answer 14

• C5 & C6
• i.e., subclavius muscle

Question 15

What is the suprascapular nerve?

Answer 15

• C5 & C6
• i.e., supraspinatus & infraspinatus

Question 16

What is the suprascapular nerve?

Answer 16

• C5 & C6
• i.e., supraspinatus & infraspinatus

Question 17

What is the lateral/medial pectoral nerve?

Answer 17

• lateral: C5, C6, & C7, i.e., pectoralis major
• medial: C8 & T1, i.e., pectoralis major/minor

Question 18

What is the upper/lower subscapular nerve?

Answer 18

• upper: C5 & C6, i.e., subscapularis muscles
• lower: C5 & C6, i.e., subscapularis & teres major

Question 19

What is the thoracodorsal nerve?

Answer 19

• C6, C7, & C8
• i.e., latissimus dorsi