Brachial Plexus
how many pairs of spinal nerves are there
31
what roots form the superior trunk of the brachial plexus?
C5,C6
What roots make up the brachial plexus?
C5-T1
the brachial plexus is a collection of nerves from which spinal levels?
C5-T1
What roots form the middle trunk?
C7
what roots form the inferior trunk?
C8,T1
name the 5 stages of plexus organization (hint there's a saying for this)
Roots (5), Trunks (3), Division (6), Cords (3), Branches (5)
what muscles does the radial nerve innervate?
all extensor muscles of arm, forearm, wrist, metacarpophalangeal joints and thumb
what are the divisions of the brachial plexus?
anterior and posterior divisions for each of the three trunks
posterior cord terminal branches are what 2 nerves?
axillary and radial
all the infraclavicular branches arise from what?
cords of the plexus
where can you find the cords beginning to form?
deep to pectoralis minor
Where can you find the start of the trunks?
deep to the inferior head of the omohyoid
what muscles does the axillary nerve innervate?
deltoid and teres minor
where is the nerve cell body located in a dorsal root
dorsal root ganglion
4 superclavicular branches are
dorsal scapular (c4,c5) root suprascapular (c5,c6) branches from superior trunk Subclavius (c5.c6) branches from superior trunk Long thoracic (c5-c7) root
the musculocutaneous nerve innervates what?
flexor muscles in anterior arm
the ulnar nerve innervates what?
flexor muscles in forearm and hand
what does the median nerve innervate?
flexor muscles in forearm and thumb
where is the nerve cell bodies in the ventral root located
in the cords and then they travel out to the ventral root
the medial cord is formed from the anterior division of what trunks?
inferior trunk
the 6 divisions then form 3 cords name them
lateral cord, medial cord, posterior cord
1 branches from the lateral cord what is this nerve
lateral pectoral nerve (c5-7)
what muscle does the thoracodorsal nerve innervate?
latissimus dorsi
3 branches from the medial cord what nerves are they?
medial pectoral nerve (c8,t1) medial brachial cutaneous nerve (c8,t1) medial antebrachial cutaneous nerve (c8,t1)
the lateral and medial cords terminal branches make up what nerve
median nerve
ventral root carries what kind of fibers
motor
the lateral cords terminal branch is what nerve
musculocutaneous
name the 5 terminal branches?
musculocutaneous, median, ulnar, radial, axillary
what does the lateral pectoral nerve innervate?
pectoralis major
what muscles does the medial pectoral nerve innervate?
pectoralis minor and major
where can you find the start of the divisions?
posterior to the clavicle
what muscles does dorsal scapular innervate?
rhomboids, levator scapulae
dorsal roots carry what kind of fibers
sensory
what fibers come together to form spinal nerves
sensory and motor
what muscles does the long thoracic innervate?
serratus anterior
what muscles does the nerve to the subclavius innervate?
subclavius
what muscle does the upper and lower subscapular nerve innervate
subscapularis
the lateral cord is formed from the anterior division of what trunks?
superior and middle trunks
the peripheral branches of the plexus fall into 3 categories name them
supraclavicular (4) infraclavicular (7) terminal branches (5)
what muscles does the suprascapular nerve innervate?
supraspinatus, infraspinatus
the axillary artery is located between what?
the anterior and posterior divisions of the brachial plexus
there are NO branches from where?
the divisions of the plexus
the posterior cord is formed from what division of all 3 trunks?
the posterior division
medial cords terminal branch is what nerve
ulnar nerve
3 branches from the posterior cord name them
upper subscapular nerve lower subscapular nerve thoracodorsal (medial) subscapular nerve
A spinal nerve is composted of 2 roots name them
ventral and dorsal
