Brachial Plexus 5 Flashcards
What happens to the dorsal rami of the spinal nn?
They stay segmented to innervate the back
The ______ rami is responsible for the formation of a plexus
Ventral rami
Name 3/4 plexuses that arise from the spinal cord and their root values
Cervical, C1-4
brachial, C5-T1
lumbosacral L2-S5
Where are the roots, trunks, divisions, cords, terminal branches?
Roots: prevertebral musculature Trunks: posterior triangle Divisions: behind clavicle Cords: in axilla Branches: throughout the upper limb
What are the 3 trunks of the brachial plexus? What forms them?
Superior/Upper: C5-6
middle: C7
inferior/lower: C8-T1
How do the trunks get their names?
Their relationship to one another.
Where do the trunks terminate?
Behind the clavicle and they become the divisions
How are the cords formed?
All 3 posterior divisions form the posterior cord. The lateral cord is formed from from the upper two anterior portions. The medial cord is formed from the lower anterior division.
How are the cords named?
For the anatomical relationship to the axillary artery
List the branches off the roots of the brachial plexus and what do they innervate?
Dorsal scapular n (C5): levator, rhomboids
Long thoracic n (C5-7): anterior serratus m
Which trunk exhibits branches? What are the nn and what do they innervate?
Superior trunk
Nerve to subclavius (C5-6): subclavius
Suprascapular (C5-6): supraspinatus, infraspinatus
What are the 3 branches from the lateral cord and what spinal cord segments do they arise from?
Lateral pectoral n (C5-7)
*Musculocutaneous (C5-7)
Lateral root of the median n (C6-7)
What do the branches of the lateral cord innervate?
Lateral pectoral n: pectoralis major
Musculocutaneous: muscles in anterior compartment (flexors)
Lateral root of the median n: median n (most flexors of forearm)
The branches of the posterior cord innervate what muscles?
Upper subscapular n: subscapularis
Thoracodorsal n : latissimus dorsi
Lower subscapular n: subscapularis and teres major
Axillary n: deltoid and teres minor
Radial n: triceps brachii and anconeus (extensors) and posterior compartment
Name the branches of the posterior cord and what spinal cord segments they arise from.
Lower and upper subscapular: C5-6
Thoracodorsal: C6-8
*Axillary: C5-6
*Radial: C5-T1 ALL
Name the branches of the medial cord and their root values
Medial pectoral n: C8-T1 Med cutaneous n of the arm: T1 Med cutaneous n of forearm: C8-T1 Medial root of median n Ulnar n: C8-T1
What do the branches of the medial cord innervate?
Medial pectoral n: pectoralis major and minor
Med cutaneous n of arm/forearm: sensory branch (no mm innervation)
Medial root of median n: median n
Ulnar n: skin and mm of forearm and hand
What three nn form the M over the surface of the axillary artery?
Musculocutaneous
Lateral root of median n
Median root of median n
Ulnar n
What is the relationship of the axillary vein to the axillary artery?
The axillary vein is superficial to the artery
What is the relationship of the median nerve to the axillary artery?
The nerve is anterior to the artery
What is the relationship of the radial n to the axillary artery?
Axillary artery is superficial to the radial nerve
