Dermatomes, Myotomes, and Spinal Nerve Plexuses Flashcards
5 Contrast segmental innervation with innervation via plexus formation
segmental innervation
a single posterior spinal root fiber innervating a single area of skin with an afferent nerve (sensory)
innervation via plexus formation
includes the effects of an entire peripheral nerve, which may include one or more dermatomes
what’s the difference between a dermatome and a nerve map?
a dermatome map includes a single sensory roots path and effect
nerve map is the map and effect of an entire peripheral nerve, which may include more than one dermatome
brachial plexus components (just the terminal branches)
musculocutaneous axillary radial ulnar median medial brachial cutaneous n. medial antebrachial cutaneous n.
Musculocutaneous
C5-C7
Median
C6-T1
Ulnar
C8-T1
Radial
C5-T1
Medial branchial cutaneous n.
C8-T2
Medial antebrachial cutaneous n.
C8-T1
Branches of lumbosacral
Femoral n Obturator n Sciatic n Lateral Femoral Cutaneous n Posterior femoral cutaneous
Femoral n.
L2-L4
Obturator
L2-L4
Sciatic n.
L4-S3
Lateral femoral cutaneous n.
L2-L3
Posterior femoral cutaneous n.
S1-S3
Lesions in C1-C7 would lead to
fully paraplegic
lesions in T1-T12
lower extremity paraplegia
lesions in L1-L5
impaired walking
lesions in S1-S5 and conus equina
impaired but good walking