Spinal Cord and Spinal Nerves

Question 1

Where does the spinal cord begin

Answer 1

as the medulla oblongata exits the foramen magnum

Question 2

Where does the spinal cord terminate

Answer 2

between L1 and L2 as the concus medullars

Question 3

What is the filum terminale

Answer 3

an extension of the pia mater of the CNS that arises from the concus medullaris and anchors the spinal cord to the coccyx

Question 4

What are the cervical and lumbar enlargements and what do they do

Answer 4

enlargement of the spinal cord in the in the cervical and lumbar regions that accommodates nerves from the upper and lower limbs respectively

Question 5

What is the cauda equina

Answer 5

horse tail

nerves that remain in the vertebral canal in fine strands after the conus medullaris

Question 6

What are the 3 meninges of the CNS

Answer 6

• Dura mater
• Arachnoid mater
• Pia mater

Question 7

Where is the epidural space and what is its fxn

Answer 7

space between the vertebral canal and the dura mater

-provides a cushion of fat and connective tissue for the spinal cord

Question 8

Where is the subdural space

Answer 8

space between the dura and arachnoid mater

it is filled w/ CSF

Question 9

Where is the subarachnoid space

Answer 9

between the arachnoid mater and the pia mater

it is filled w/CSF

Question 10

Which of the meninges contains blood vessels that supply O2 and nutrients to the spinal cord

Answer 10

Pia mater

Question 11

What is the grey commissure of the spinal cord

Answer 11

forms the crossbar of the H like structure of the spinal cord grey matter

Question 12

What area of the spinal cord is associated w/ the somatic motor neurons

Answer 12

the anterior grey horns

Question 13

What area of the spinal cord is associated w/ the somatic and autonomic sensory neurons

Answer 13

the posterior grey horns

Question 14

`What area of the spinal cord is associated w/ the autonomic motor neurons

Answer 14

the lateral grey horns, only present in T1-L2 and S2-S4 of the spinal cord

Question 15

True or False the central canal extends from the 4th ventricle down the entire length of the spine

Answer 15

True

Question 16

What is the role of grey matter in the spine

Answer 16

it receives and integrates incoming and outgoing messages

Question 17

Name the 3 areas of white matter in the spinal cord

Answer 17

1. Anterior columns
2. Lateral columns
3. Posterior columns

Question 18

What is another name for sensory tracts

Answer 18

ascending

Question 19

What is another name for motor tracts

Answer 19

descending

Question 20

What are the 2 bundles of axons that connect each spinal nerve to a segment of the cord

Answer 20

The posterior root and the anterior root

Question 21

How many spinal nerves are there

Answer 21

31 pairs ie 62 total

8 pair cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal

Question 22

Define the intervertebral formaina

Answer 22

the opening between the adjoining vertebrae

Question 23

How are spinal nerves named

Answer 23

Spinal nerve names correlate with the region and level when they exit from the vertebral column not the where they emerge from the spinal column

Question 24

What causes the observed offset of the spinal nerve names with their exit from in between vertebrae

Answer 24

Spinal cord stops growing at ~age 4-5 but vertebral column continues to grow

Question 25

Where does the first cervical pair of spinal nerves emerge

Answer 25

Between the occipital bone of the skull and the atlas (C1)

Question 26

Do the cervical spinal nerves emerge inferiorly or superiorly of the vertebrae with the same number and why is this odd

Answer 26

superiorly all the other spinal nerves exit inferiorly to the vertebrae with the same

Question 27

What happens to the spinal nerve once it emerges from the vertebral column

Answer 27

it almost immediately divides into the dorsal primary ramus and ventral primary ramus

Question 28

What do posterior (dorsal) rami innervate

Answer 28

deep muscles and skin of the dorsal trunk

Question 29

What do anterior(ventral) rami innervate

Answer 29

muscles of the upper and lower limbs and the skin of the lateral and ventral surfaces of the trunk

Question 30

Where does the meningeal branch of the spinal nerve go after dividing off

Answer 30

It reenters the vertebral canal to supply the vertebrae

Question 31

What are plexuses

Answer 31

networks of axons that form from the anterior rami of adjacent spinal nerves they contain both motor and sensory neurons

Question 32

What are the principle plexuses of the body

Answer 32

- Cervical plexus - Brachial plexus - Lumbar plexus - Sacral plexus - Coccygeal plexus

Question 33

Why isn't there a thoracic plexus

Answer 33

because the thoracic spinal nerves go directly to the body structures they supply and do not form a networks of axons

Question 34

What is another name for the anterior rami of thoracic spinal nerves (T2-T12)

Answer 34

Intercostal nerves

Question 35

What areas of the body does the cervical plexuses supply

Answer 35

The diaphragm and the skin and muscles of the head, neck, superior of the shoulders and chest

Question 36

What are the phrenic nerves

Answer 36

nerves that arise from c3,4 and 5 an enter cervical plexuses that supply the motor fibers of the diaphragm

Question 37

What happens if the spinal cord is severed above C5

Answer 37

breathing stops because the phrenic nerves can no longer send impulses to the diaphragm

Question 38

What areas of the body does the brachial plexuses supply

Answer 38

the shoulders and upper limbs

Question 39

What are the subunits of the brachial plexus

Answer 39

Root/ramus, Trunk, Division, Cord, Branch Mnemonic= Read The Damn Cadaver Book

Question 40

What are the radial nerves

Answer 40

nerve that arises from the brachial plexuses and supplies the muscles of the posterior aspect of the arm and forearm

Question 41

What does radial nerve injury result in and how can it happen

Answer 41

- results in wrist drop | - caused by improper IM injection to deltoid or a cast being too tight around the mid-humerus

Question 42

What areas of the body does the lumbar plexuses supply

Answer 42

the anterolateral abdominal wall, external genitals, and part of the lower limbs

Question 43

What areas of the body does the sacral plexuses supply

Answer 43

the buttocks, perineum, and lower limbs

Question 44

What are the sciatic nerves

Answer 44

largest nerve in the body, that emerges from the sacral plexus

Question 45

True or False the sciatic nerve is actually 2 nerves

Answer 45

True, they are bound by a common sheath

Question 46

What is sciatica

Answer 46

pain that extends down the buttock to the foot that can result from a herniated disc, dislocated hip, OA, pregnancy, or improper IM injection in the gluteal muscles