Canine Thoracic Limb: Neurology

The nerves that innervate the thorax limb arise from the _________ _________

brachial plexus

brachial plexus

collection of nerves that get their origin from the ventral branches of cervical and thoracic spinal nerves C6-8 and T1-2

Coming off of the spinal cord is a _______ and _______ root

dorsal; ventral

dorsal root

the sensory branch of each spinal nerve

ventral root

the motor branch of each spinal nerve

When the dorsal and ventral root fuse, they form a....

spinal nerve proper

The spinal nerve proper then branches into....

Four primary branches, including a ventral branch (that innervates the thoracic limb)

The brachial plexus nerves emerge from _____________ foramina

intervertebral

Eleven named nerves from the brachial plexus

1.) pectoral

2.) suprascapular

3.) subscapular

4.) axillary

5.) thoracodorsal

6.) lateral thoracic

7.) long thoracic

8.) musculocutaneous

9.) median

10.) radial

11.) ulnar

pectoral nerve

innervates all the pectoral muscles

suprascapular nerve

innervates supraspinatus and infraspinatus muscles

Where is the suprascapular nerve located?

dives on the medial side between subscapularis and supraspantus muscles, then courses around the scapula to the lateral side to reach its target muscles

subscapular nerve

innervates subscapularis

Where is the subscapular nerve located?

directly enters the subscapularis muscle on the medial side of limb

axillary nerve

innervates deltoideus, teres major, and teres minor

where is the axillary nerve located?

dives between the teres major and subsacpularis, then courses toward the lateral side of shoulder to reach deltoideus and teres minor

thoracodorsal nerve

innervates latissimus dorsi

lateral thoracic nerve

innervates cutaneous trunci muscle, and ventrolateral abdominal wall

long thoracic nerve

innervates serratus ventralis

musculocutaneous nerve has three branches:

1.) proximal muscular branch

2.) distal muscular branch

3.) communicating branch

proximal muscular branch of the musculocutaneous nerve

innervates coracobrachialis and biceps brachii

distal muscular branch of the musculocutaneous nerve

innervates brachilais

communicating branch of the musculocutaneous nerve

fuses with median nerve

The median nerve gives rise to the...

medial cutaneous antebrachial nerve

medial cutaneous antebrachial nerve

innervates the medial skin of the antebrachium

median nerve

-motor innervation to flexors of the carpus and digit

-sensory innervation to skin of caudal antebrachium and caudal paw

What specific flexor muscles does the median nerve innervate?

1.) pronator teres

2.) pronator quadratus

3.) deep digital flexor (all three heads)

4.) superficial digital flexor

5.) flexor carpi radialis

ulnar nerve

-motor innervation to flexors of the carpus and digit

-sensory innervation to skin of caudal antebrachium, skin of lateral metacarpus and digit, and palmar paw

What specific flexor muscles does the ulnar nerve innervate?

1.) flexor carpi ulnaris (both heads)

2.) deep digital flexor (ulnar and humeral head)

3.) interosseous

The ulnar nerve gives rise to the....

cadual cutaneous antebrachial nerve

cadual cutaneous antebrachial nerve

sensory innervation to:

-skin of caudal antebrachium

-skin of lateral metacarpus and -palmar paw

radial nerve innervates three groups:

1.) elbow extensors

2.) carpus and digit extensors

3.) skin

Three elbow extensors that radial nerve innervates

1.) triceps brachii

2.) tensor fascia antebrachii

3.) anconeus

Six carpus and digit extensors that radial nerve innervates

1.) extensor carpi radialis

2.) common digital extensor

3.) lateral digital extensor

4.) ulnaris lateralis

5.) supinator

6.) abductor pollicus longus

Skin that radial nerve innervates

skin of cranial and lateral antebrachium and dorsal paw