Thoracic Limb Nerves

Question 1

What segment gives origin to the nerves supplying the thoracic limb?

Answer 1

Cervical intumescentiae (C6-T2)

Question 2

What is the brachial plexus?

Answer 2

Network of nerves formed by ventral branches of spinal nerves (+/-C5) C6, C7, C8, T1, T2
Supply the thoracic limb
Motor to skeletal muscles
Cutaneous sensory from skin and propioception from thoracic limb

Question 3

Where can you find the brachial plexuses on a specimen?

Answer 3

Axillary regions in close relation with the axillary vessels

Question 4

What must nerves have to have an overlap zone or autonomous zone?

Answer 4

Nerve must have a cutaneous area to have an OZ or AZ

Question 5

Nerves of brachial plexus can be broken into which two groups?

Answer 5

Extrinsic and Intrinsic groups

Question 6

What muscle does the Brachiocephalic n innervate?

Answer 6

Cleidobrachialis m.

Question 7

What muscle does the cranial pectoral nn innervate?

Answer 7

Superficial pectoral m.

Question 8

What muscle does the caudal pectoral nn innervate?

Answer 8

Deep pectoral m.

Question 9

What muscle does the thoracodorsal n innervate?

Answer 9

Latissimus dorsi m

Question 10

What muscle does the Long thoracic n innervate?

Answer 10

Serratus ventralis m

Question 11

What muscle does the lateral thoracic n innervate?

Answer 11

Cutaneous trunci m (not extrinsic m)

Question 12

Which two nerves of the brachial plexus are only motor n?

Answer 12

Suprascapular n
Subscapular n

Question 13

Name the nerves of the brachial plexus that innervate the intrinsic thoracic limb muscles?

Answer 13

1.) Suprascapular n (motor)
2.) Subscapular n (motor)
3.) Musculocutaneous n (both)
4.) Axillary n (both)
5.) radial n (both)
6.) Median n (both)
7.) Ulnar n (both)

Question 14

What muscle(s) does the Suprascapular n innervate?

Answer 14

Supraspinatus m
Infraspinatus m

Question 15

What muscle(s) does the Subscapular n innervate?

Answer 15

Subscapularis m

Question 16

What muscle(s) does the Musculocutaneous n innervate?

Answer 16

Biceps brachii m
Brachialis m
Coracobrachialis m

Question 17

Where is the sensory innervation for the Musculocutaneous n?

Answer 17

medial aspect for the antebrachium

Question 18

What muscle(s) does the Axillary n innervate?

Answer 18

Teres major m
Teres minor m
Deltoideus m
Caudal part of the subscapularis m

Question 19

What actions would be effected by severing the axillary nerve?

Answer 19

Flexion of humeral joint

Question 20

Where is the sensory innervation of the Axillary n?

Answer 20

Craniolateral shoulder area

Question 21

What actions would be effected by severing the Musculocutaneous n?

Answer 21

Flexion of the cubital joint and extension of the humeral joint

Question 22

What muscle(s) does the radial n innervate in the brachial region?

Answer 22

Triceps brachii m
Tensor fasciae antebrachii m
Anconeus m

Question 23

What actions would be effected if the radial nerve was severed?

Answer 23

Extension of cubital joint and Flexion of humeral joint
Extension of carpal and digital joints
Supination of manus

Question 24

What muscle(s) does the radial n (deep branch) innervate in the antebrachial region?

Answer 24

Extensor carpi radialis m
Common digital extensor m
Lateral digital extensor m
Extensor carpi ulnaris m
Supinator m

Question 25

Where is the sensory innervation of the superficial branch of the radial n?

Answer 25

Cranial and lateral aspect of antebrachium Medial and dorsal aspect of manus

Question 26

What is the superficial branch of the radial n called?

Answer 26

Antebrachiocutaenous nn

Question 27

What muscle(s) does the Median n innervate?

Answer 27

Pronator teres m Flexor carpi radialis m Superficial digital flexor m Deep digital flexor m Pronator quadratus m

Question 28

What actions would be effected if you severed the median n?

Answer 28

Flexion of the carpal and digital joints Pronation of the manus

Question 29

Where is the sensory innervation of the median n?

Answer 29

Palmar aspect of the manus

Question 30

What muscle(s) does the Ulnar n innervate?

Answer 30

Flexor carpi ulnaris m Deep digital flexor m Interossei mm

Question 31

What actions would be effected if the ulnar n was severed?

Answer 31

Flexion of carpal and digital joints

Question 32

Where is the sensory innervation of the ulnar nerve?

Answer 32

Caudal aspect of antebrachium Palmar aspect of manus Lateral side of digit V

Question 33

What is the caudal aspect of the antebrachium innervation of the ulnar n called?

Answer 33

Caudal antebrachial cutaneous n