Brachial plexus Flashcards
What is the brachial plexus?
Network of spinal nerves (C-5 through T-1) that provide innervations to upper extremity + shoulder areas
parts of the brachial plexus in order
- roots
- trunks
- divisions
- cords
- branches
Where is the root located?
btwn anterior + middle scalene
where is the trunk located?
posterial cervical triangle (divided by SCM), near clavicle
where are the divisions located?
deep to the clavicle
where are the cords located?
deep to axilla beneath pec minor, adjacent to axillary artery
where are the branches located?
inside coracobrachial muscle
what are the sensory part of the nerves called?
dermatomes
what are the motor part of the nerves called?
myotomes
what are the 3 nerves that come off the roots?
- dorsal scalpula
- long thoracic
- phrenic
what is the dorsal scapula formed from? what does it innervate?
formed form C5
innervates: rhomboids (major + minor), levator scapulae which elevates scalpula
what does the long thoracic nerve innervate?
serratus anterior
what does the phrenic nerve innervate?
the diaphragm which helps in breathing
what are the 3 levels of the trunks and what are they formed from?
- superior: C5-C6
- middle: C7
- inferior: C8-T1
what are the nerves of the superior trunk and what do they innervate?
- suprascalpular nerve: innervates supraspinatus + infraspinatus muscles
- subclavius nerve: innervates subclavius
what are the nerves of the middle and inferior trunks?
no nerves
how are the divisions formed?
from the bifurcation of the 3 trunks
how does the axillary artery run in relation to the cords?
the cords travel adjacent to axillary artery
• Behind it is the posterior cord
• Name reflects its position to axillary artery
What are the cords?
- lateral
- medial
- posterior
what are the nerves of the lateral cord?
- lateral pec nerve
- musculotaneous nerve
- medial nerve
what is the innervation of the lateral pec nerve of the lateral cord?
clavicular head
what is the innervation of the musculotaneous nerve of the lateral cord? what does it supply?
• biceps brachii,
• coracobrachialis,
• brachialis
supplies sensory part of anterior forearm (lateral antebrachial cutaneous nerve)
what is the innervation of the median nerve of the lateral cord?
skin on anterior forearm and palm but no muscles
flexors, pronators of the anterior forearm except 1.5 muscles, numerous muscles in the wrist + palmar hand
what are the nerves of the medial cord?
- Medial pectoral nerve
- Medial brachial cutaneous nerve
- Median nerve
- Ulnar nerve
what does the medial pec nerve innervate?
pec minor, sternal head of pec major
what does the medial brachial cutaneous nerve innervate?
Skin of middle arm
what does the median nerve innervate?
flexors, pronators of the anterior forearm except 1.5 muscles, numerous muscles in the wrist + palmar hand
what does the ulnar nerve innervate?
1.5 muscles in anterior forearm + numerous wrist muscles
what are the nerves of the posterior cord?
- Axillary nerve
- Upper subscapular
- Lower subscapular
- middle subscapula
- radial
what does the axillary nerve innervate?
teres minor + deltoid muscles
what does the upper subscapular nerve innervate?
superior portion of subscalpularis (under scalpula)
what does the lower subscapular nerve innervate?
lower subscalpularis + teres major
what does the middle subscapular nerve innervate?
latissimus dorsi (wide muscle on back)
what does the radial nerve innervate?
all muscles of posterior arm + forearm + wrist
AKA Supplies all Extensors and supinators
