Spinal Nerves & Brachial Plexus

asnotley's version from 2017-12-29 16:06


Question Answer
Spinal nerves are ___ nervesmixed
Cervical nerves (C1-C7) exit ___ corresponding vertebraeabove
all other nerves except cervical (T1-Co1) exit ___ corresponding vertebraebelow
C8 exit where?comes out below C7 and above T1
Pathway for motor informationVentral horn -> ventral rootlets -> ventral root -> spinal nerve -> dorsal/ventral rami
Pathway for sensory informationdorsal/ventral rami -> spinal nerve -> dorsal root -> dorsal rootlets -> dorsal horn
ventral rami functionMOTOR to muscle of limbs and trunk, and SENSORY from skin of limbs and trunk
dorsal rami functionMOTOR to deep back muscles, SENSORY from skin on back
dermatomes lesion (lesion to spinal nerve)lesion to spinal nerve = decreased sensation of skin innervated by that nerve (partial loss)
b/c more than 1 spinal nerve innervate a particular area, if you lesion 1, it's ok, theres more
myotomes lesion (lesion to spinal nerve)lesion to spinal nerve results in partial paralysis/weakness of muscle
brachial plexusnetwork of nerves supplying the upper limb, intermingling of nerves in the neck and axilla forming a plexus, ventral rami of C5-T1, plexus resulted in mixed terminal branches (more than 1 spinal nerve supplying skin and muscle)
lesion to peripheral nervecomplete loss of sensation/complete muscle paralysis
because more than 1 rami is innervating the area (combination of all ramis)
Lesion in C5-C6can't abduct, internal (medially) rotation, pronation (can't flex)
Lesion in C8-T1all fingers clawed, forearm flexors and extensors lost

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