Thoracic Limb Innervation Flashcards
What does innervation of the thoracic limb include?
Motor innervation
Sensory innervation
Autonomic innervation
Motor innervation
To skeletal muscles, through the ventral branches of the spinal nerves (motor nerves)
Sensory innervation
To the skin, through the ventral branches of spinal nerves (cutaneous branches)
Autonomic innervation (ANS)
To the smooth muscles and glands through the sympathetic portion of the autonomic nerves that join the spinal nerves
Brachial Plexus
C6-T2
Network of the ventral branches of the cervical spinal nerves (C6-8) and the 1st and 2nd thoracic spinal nerves (T1, T2)
The brachial plexus gives origin to the nerves that innervate what structures?
- Thoracic limb
- Parts of the shoulder muscles
- Lateral wall of the thorax/ abdomen
- Diaphragm (phrenic nerve)
Suprascapular nerve
Origin: C6 and C7
Courses in between the supraspinatus and the subscapularis
S: supraspinatis and infraspinatus muscles
What does the suprascapular nerve pass?
Around the neck of the scapula
Across the scapular notch (vulnerable to trauma)
Clinical significance of the Suprascapular nerve
Shoulder slip- injury leads to muscle atrophy
Musculocutaneous Nerve
Arises from C6, C7, C8 (caudal to the suprascapular)
What nerve won’t give you any problems?
The subscapular nerve
What does the muscular branch of the musculocutaneous nerve innervate?
Biceps brachii, coracobrachialis and Brachialis (flex elbow)
What does cutaneous branch mean?
Branch to the skin and sensory
Cutaneous branch of the musculocutaneous nerve
Medial cutaneous antebrachial nerve
Runs between flexor carpi radialis and pronator teres
What is the function of the medial cutaneous antebrachial nerve?
Innervate the medial aspect of the antebrachium
Axillary Nerve
Origin: C7 and C8
Motor innervation of the axillary nerve
Innervates teres major, teres minor, deltoideus and the subscapular muscles
Sensory branches of the axillary nerve
- Cranial lateral cutaneous brachial: Innervate the lateral surface of brachium, cd. scapular
- Cranial cutaneous antebrachial: cr. antebrachium