organization of spinal nerves - lecture 5

Question 1

what is every spinal cord connected to

Answer 1

a pair of spinal nerves

Question 2

what is each spinal cord segment surrounded by

Answer 2

3 connective tissue layers

that support structures and contain blood vessels

Question 3

3 connective tissue layers

Answer 3

epineurium

perineurium

endoneurium

Question 4

epineurium

Answer 4

outermost layer

dense network of collagen fibers

Question 5

perineurium

Answer 5

middle layer

divides nerves into fascicles

axon bundles

Question 6

endoneurium

Answer 6

inner layer

surround individual axons

Question 7

what happens almost immediately after emerging from its intervertebral foramen (Spinal nerves)

Answer 7

will divide into a dorsal ramus, ventral ramus and a meningeal branch

the meningeal branch re-enters and innervates the meninges and associates with blood vessels

each ramus is mixed

Question 8

what is joint to the base of the ventral rami of spinal nerves

Answer 8

in the thoracic region

rami communicantes

these are sympathetic fibers

Question 9

what do dorsal rami supply

Answer 9

the posterior body trunk

Question 10

what do the ventral rami supply

Answer 10

thicker

rest of the body (trunk and limbs)

Question 11

what ventral rami form interlacing networks

Answer 11

all but T2-T12

these networks are called plexuses

Question 12

what does each resulting branch of a plexus contain

Answer 12

fibers from several spinal nerves

Question 13

where does each muscle receive a nerve supply from

Answer 13

more than one spinal nerve

Question 14

can damage to one spinal segment completely paralyze a muscle?

Answer 14

no

Question 15

cervical plexus

Answer 15

formed by ventral rami of C1-C4

Question 16

what are most branches of the cervical plexus

Answer 16

cutaneous nerves of the neck, ear, back of head and shoulders

Question 17

where is the cervical plexus located

Answer 17

neck

deep to SCM

Question 18

what does the cervical plexus contain

Answer 18

phrenic nerve

lesser occipital nerve

greater auricular nerve

accessory nerve (C3-C4)

Question 19

what is the brachial plexus formed by

Answer 19

ventral rami of C5-C8 and T1

C4 and T2 may also contribute to this plexus

Question 20

what does the brachial plexus supply

Answer 20

nerves of the upper limb

Question 21

lumbar/sacral plexus

Answer 21

arises from L1-L4 and L4-S4

Question 22

what does the lumbar/sacral plexus innervate

Answer 22

thigh

abdominal wall

psoas muscle

the buttock

lower limb

pelvic structures

perineum

Question 23

dermatomes

Answer 23

always check sensation before testing myotomes or muscle strength