Spinal nerve roots/rootlets Flashcards Preview

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Flashcards in Spinal nerve roots/rootlets Deck (24):
1

Ventral nerve roots

Series of only motor roots in the GVE and GSE respsctive to each spinal cord segment that go to the periphery

2

What is a nerve root a composite of?

Rootlet

3

What protion of the spinal cord do ventral nerve rootlets form off of?

Ventral lateral sulcus

4

Dorsal nerve roots

  • Series of  only sensory roots (respective to each spinal cord segment) that collects to form the sensory axons to the spinal cord
  • collection of central axonal processes from the pseudounipolar neurons in the dorsal root ganglions (directly medial to the root)

5

Dorsal root ganglion

  • Aka the spinal ganglion/ posterior root ganglion
  • the "bump" directly medial to the dorsal nerve root
  • where all spinal nerve sensory nerve bodies are found

 

6

Central Axon Processes

One branch of the pseudounipolar neurons found in the spinal ganglion (the other is peripheral)

7

Where do dorsal rootlets enter the spinal cord?

Dorsal lateral sulcus

8

Spinal nerve

  • formed near the intervertebral foramen/ distal to spinal ganglion
  • ventral/dorsal nerve roots join to form this (same vertebral level)
  • has both motor and sensory fibers

9

# of nerve pairs per a division of the spinal cord

8 cervical – 12 thoracic – 5 lumbar – 5 sacral – 1 coccygeal

10

How are cervical spinal nerves named?

What vertebrae they pass superior to

11

How are thoracic and lumbar nerves named?

By what vertebrae they pass inferior to

12

How do the spinal nerves change the more inferior they exit along the spinal cord?

Lower spinal nerves are much longer and have to travel inferiorly before traveling obliquely so they exit at the correct vertebral level

13

Sacral spinal nerves

  • Are found in the sacral canal (S1-S4)
  • Each must branch into ventral and dorsal rami before exiting via the ventral/dorsal sacral foramina

14

Which nerves exit via the sacral hiatus?

S5 and Co1 (coccygeal)

15

Cauda equina

Dorsal/ventral roots of L2 to Co that emerge from the conus medullaris

16

Dorsal/Ventral Rami

  • Lateral division of the spinal nerve that extends to/from the target nerve ending
  • Each contains both afferent and efferent fibers

17

Dorsal Rami

Innervate skin, muscles, joints, of vertebral column/nearby structures

18

Ventral rami

  • Innervate all structures anterior to the vertebral column including: limb structures/embryological derivates
  • Much larger than dorsal rami

19

Dermatome

  • Area of skin innervate by a single spinal cord segment
  • Sensory cell bodies are in dorsal root ganglia

20

Torso dermatome pattern

Banded with some overlap

21

High yield dermatomes

T4 – Nipples; T10 – umbilicus; C6 –pad of thumb;

C8 – pinky; S5 – anus

22

Dermatomes and herpers zoster

Shingles presents as a stripped pattern on the torso because virus lives in the nerve cell bodies with the spinal ganglia

23

Limb dermatome pattern

Does not match the peripheral nerve due to plexuses

24

General segmental muscle innervation rule

Most muscles are innervated via 2 or more spinal nerves and 1 spinal nerve may help to supply many muscles