Peripheral Nerve Anatomy Flashcards
peripheral nerves
-continuation from spinal anatomy -spinal nerves split, converge, and branch - form peripheral nerves
Cervical Plexus
Innervates - muscles, joints, and skin in the anterior neck - Ventral Rami C1-C4
Brachial Plexus
Large network of nerves - extend from neck through axilla Innervate the upper extremity Composition -
ventral Rami (Roots) 5 -
Trunks 3 -
Divisions 6 -
Cords 3 -
Branches 4
BP: Roots, Trunks, and Divisions
- Found in posterior triangle of the neck - Supraclavicular
BP: Cords and Branches
-Found in the Axilla - Infraclavicular
BP: Roots
- 5 Rami (Roots) involve C5-T1 - May include C4 and T2
- Pass to lateral border of scalene muscles
- Reorganize to 3 Trunks
BP: Trunks
3 Trunks - Superior C5-C6
-Middle C7
-Inferior C8-T1
Enveloped in fascial sheath
- Interscalene space - between anterior and middle scalene muscle
- Injection into sheath - commonly produces complete block of upper extremity
- May have individual septa - thus we see incomplete blocks
BP: Divisions
Posterior to clavicle divide into:
- 3 ventral (Anterior) divisions-supply flexor portions
- 3 Dorsal (Posterior) Divisions - supply extensor portions
BP: Cords
In axilla:
- 3 Dorsal Divisions combine to form posterior cord
- 3 Ventral divisions combine to form lateral and medial cords
- Now name in position to axillary artery
BP: Branches
- At lateral border of pectoralis minor
- each cord divides into 2 branches
- become peripheral nerves
- Lateral Cord, Medial Cord, Posterior Cord
Lateral Cord
- Musculocutaneous nerve
- Lateral root of median nerve
Medial Cord
- Medial root of medial nerve
- Ulnar Nerve
Posterior Cord
- -Axillary Nerve
- -Radial Nerve
Axillary Nerve
- Formed from C5-C6
- Passes from axilla to shoulder
- Posterior to the neck of humerous
- Innervation - Deltoid and skin covering it
Radial Nerve
Formed from fiber of C5-T1
- Passes from axilla to arm*
- Innervates long head of triceps
- -posterior brachial cutaneous branch
- -innervates skin covering the muscle
Descends along shaft of humerous
- -Inferior lateral cutaneous branch innervates posterior arm
- -Posterior antebrachial cutaneous branch innervates surface of forearm
- Crosses elbow anterior to lateral epicondyle*
- Divides into deep and Superficial branch
- -Superficial continues down to hand innervates dorsum of the hand onto the thumb, index, middle, and ring fingers
- Deep innervates many of the muscles of wrist and hand
Radial Nerve: Response to stimulation
- wrist extension
- metacarpo-phalangeal extension
- thumb abduction