Nerves of Thoracic Limb Of Dog

Question 1

What is the axillary artery a continuation of and where does it extend from?

Answer 1

Continuation of the subclavian and extends from the first rib

Question 2

Where does the axillary nerve extend to?

Answer 2

Extends to the conjoined tendons of the teres major and latissimus dorsi

Question 3

What are the 4 branches of the axillary artery?

Answer 3

(In order of which they branch off) external thoracic artery, lateral thoracic artery, subscapular artery and cranial circumflex humeral

Question 4

What is the brachial plexus?

Answer 4

Ventral branch of cervical nerves C6-C8 (sometimes C5) and thoracic nerves T1-T2 intermesh and exchange fibres. All major nerves of forelimb originate here.

Question 5

Which spinal nerves does the suprascapular nerve branch from?

Answer 5

C6-C7

Question 6

Where is the suprascapular nerve found?

Answer 6

Between the supraspinatus and subscapularis muscles

Question 7

What does the suprascapular nerve innervate?

Answer 7

Supraspinatus and infraspinatus muscles. Supports shoulder laterally, abducts limb

Question 8

What happens when the suprascapular nerve is injured?

Answer 8

Atrophy if shoulder muscles, scapula spin becomes more prominent, animal can walk but has lateral slip

Question 9

Does the suprascapular nerve have any cutaneous innervation?

Answer 9

No

Question 10

What spinal nerves does the subscapular nerve branch from?

Answer 10

C6-C7

Question 11

Where does the subscapular nerve branch to?

Answer 11

Subscapularis muscle

Question 12

What does the subscapular muscle nerve innervate?

Answer 12

Subscapularis muscle: supports joint medially, adducts limb. No cutaneous branches

Question 13

What spinal nerves does the musculocutaneous nerve branch from?

Answer 13

C6-C7

Question 14

Where is the musculocutaneous nerve found?

Answer 14

Descends medial surface of the brachium and has communicating branch with median nerve

Question 15

What does the musculocutaneous nerve innervate?

Answer 15

Biceps brachii, brachialis, coracobrachialis muscles to flex the elbow

Question 16

What sensory innervation does the musculocutaneous nerve have?

Answer 16

Medial antebrachium

Question 17

What happens when this nerve is injured?

Answer 17

Loss of sensation of medial antebrachium, slight straightening of elbow, difficulty raising paw, compensation adaption from carpal extensors and pronator teres muscles

Question 18

What spinal nerves does the axillary nerve come from?

Answer 18

C7-C8

Question 19

What does the axillary nerve innervate?

Answer 19

Teres major and minor muscles and deltoideus muscle (to flex shoulder)

Question 20

What cutaneous sensation does the axillary nerve innervate?

Answer 20

Lateral brachium and proximal antebrachium

Question 21

Where is the axillary nerve found?

Answer 21

Space between subscapularis muscle and teres major muscle

Question 22

What happens when the axillary nerve is injured?

Answer 22

Loss of cutaneous sensation over lateral brachium and proximal antebrachium, loss of function of shoulder flexors, compensation adaptation from latissimus dorsi muscle and long head of triceps muscle

Question 23

Where is the radial nerve found?

Answer 23

Leaves axilla, travels through triceps, accompanies brachialis muscle around lateral aspect of humerus, flexor surface of elbow, divides into deep and superficial

Question 24

What does the radial nerve innervate?

Answer 24

Triceps brachii and tensor fascia antibrachii muscles (to extend elbow). Extensor carpi radialis, common digital extensor, lateral digital extensor, ulnaris lateralis, abductor pollicis longus muscles (to extend carpal and digits), supinator muscle

Question 25

What cutaneous sensation does the radial nerve innervate?

Answer 25

Cranial and lateral antebrachium, dorsal law

Question 26

What spinal nerves does the axillary nerve branch from?

Answer 26

C7-C8

Question 27

Where does the axillary nerve lie?

Answer 27

Between the subscapularis and teres major muscle

Question 28

What does the axillary nerve innervate?

Answer 28

Teres major and minor muscles and deltoideus to flex the shoulder joint

Question 29

What cutaneous sensation does the axillary nerve innervate?

Answer 29

Lateral brachium and proximal antebrachium

Question 30

What happens if the axillary nerve is injured?

Answer 30

loss of cutaneous sensation over lateral brachium and proximal antebrachium, loss of function of shoulder flexors, compensation adaptation from latissimus dorsi and long head of triceps muscle.

Question 31

What spinal nerves does the radial nerve branch from?

Answer 31

C7-T1

Question 31

What happens if the radial nerve is injured?

Answer 31

Level of dysfunction depends of where nerve is injured, severe proximal damage is catastrophic (proximal: limb useless, elbow drops, knuckling of paw), distal damage (knuckling, some weight bearing possible can learn to flip paw. Cutaneous sensation lost

Question 32

What spinal nerve does the median nerve branch from?

Answer 32

C8-T1

Question 33

Where is the median nerve found?

Answer 33

Medial surface, cranial to elbow medial collateral ligament, under pronator teres muscle and flexor carpi radialis muscle, continues under flexor carpi radialis

Question 34

What does the median nerve innervate?

Answer 34

Flexor carpi radialis, superficial digital flexor, deep digital flexor muscles ( carpal and digital exentsors). Pronator teres and pronator quadratus muscles (pronators). Sensory:palmar paw

Question 35

What spinal nerves does the ulnar nerve come from?

Answer 35

C8-T1

Question 36

Where does the ulnar nerve lie?

Answer 36

Initially descends with median nerve, becomes more caudal distally over medial epicondyle of humerus. Cutaneous branch on medial aspect of olecranon.

Question 37

What does ulnar nerve innervate?

Answer 37

Flexor carpi ulnaris and deep digital flexor muscles (carpal and digital extensors)

Question 38

What sensory does the ulnar nerve innervate?

Answer 38

Caudal antebrachium, lateral surface 5th digit, palmar paw ( with median)

Question 39

What happens if median and ulnar nerves are injured?

Answer 39

Not crucial for locomotion, slight sinking at metacarpophalangeal joints, doesn’t result in lameness, loss of cutaneous sensation