L-20 Flashcards
What is the foremen magnum?
Opening at the base of the skull
Where are the parameters of the spinal chord?
Starts at foremen magnum and ends at inferior boarder of the 1st lumbar vertebrae
Where does the spinal chord sit?
Within a meningeal sac in the spinal cavity
how far does the meningeal sac extend?
To the coccygeal
Why does the meningeal sac extend so far below the spinal chord?
Allows the Filum terminale to anchor the spinal chord to the coccygeal
Where does the Filum Terminale attach to?
Superiorly the conus medularis
Inferiorly the coccygeal
What is the conus medularius?
Tapered cone end of the spinal chord
What are the conus medularis and the Filum terminale made of?
Non-neural tissue
How many segments make up the spinal chord?
31
How do we name spinal nerves and what is the exeption?
Names after the segment they exit below except for cervical spinal nerves because there is one extra between the skull and the first vertebra
Why do the axons of the spinal nerves increase in length further down the spine?
The spinal chord is shorter than the spine and they exit through their associated vertebra
What is the Cauda equina?
The large collection of nerves (axons) inferior to the end of the spinal chord
Which nerve roots does efferent information leave through?
Ventral
Which nerve roots does afferent information enter through?
Dorsal
How do we tell which side of the spinal chord is ventral?
- Anterior median fissure
- root ganglion is dorsal
- butterfly top wings are dorsal
How many branches does the spinal nerve split into immediately after leaving the spinal chord? Name them
- 3
- Dorsal Ramus Branch
- Ventral Ramus Branch
- Rami communicants connect to sympathetic chain ganglia
What does the dorsal Ramus branch do?
Carries information to and from the back
What does the ventral ramus do?
Carries information to and from the ventral body
Where do the rami communicans lead?
The sympathetic chain ganglia
What is the name of the covering sheath of axons+ myelin?
Endoneurium
What is the endoneurium?
Covering of the axon+ myelin in a peripheral nerve
What is the name for a bundle of covered axons in a peripheral nerve?
Fascicle
What is a fascicle in a peripheral nerve?
A bundle of covered axons
What is the name of the covering of fascicles in a peripheral nerve?
Perineurium
What does perineurium do in a peripheral nerve?
Covering sheath of fascicles
What is the name for a bundle of fascicles and blood vessels?
A peripheral nerve
What is the name of the covering of a peripheral nerve?
Epineurium
What is the role of epineurium in the PNS?
Covers the Peripheral nerves
