The Spinal Cord and Meninges Flashcards
Where does the spinal cord begin?
medulla oblongata
Where does the spinal cord end?
L1/L2
Why is the spinal cord enlarged at the cervical and lumber regions?
Cervical and lumbar enlargement of the spinal cord is due to the fact that these regions have outflow which innervates the limbs.
Nerves which exit from the cervical region of the spine form the ______ plexus and innervates the ______ limbs.
Nerves which exit from the cervical region of the spine form the brachial plexus and innervates the upper limbs
Nerves which exit from the lumbar region of the spine form the ______ plexus and innervates the ________ limbs.
Nerves which exit from the cervical region of the spine form the lumbar sacral plexus and innervates the lower limbs.
How many vertebrae are in the cervical region of the spinal cord and how many pairs of spinal nerves exit from the cervial region.
There are 7 vertebrae in the cervical region and 8 pairs of spinal nerves
How many vertebrae and pairs of spinal nerves are there in the thoracic region of the spinal cord?
12 vertebrae and 12 pairs of spinal nerves
How many vertebrae and pairs of spinal nerves are there in the lumbar region of the spinal cord?
5 vertebrae and 5 pairs of spinal nerves
How many vertebrae and pairs of spinal nerves are there in the sacral region of the spinal cord?
5 vertebrae and 5 pairs of spinal nerves
How many spinal nerves are there in the coccygeal region of the spinal cord?
1 spinal nerve
What is the name of the nerves that extend past the bottom of the spinal cord?
Cauda Equina
What is the name of the foramen through which the nerves leave the spinal cord?
Intervertebral column
What is the name of the tapered, inferior end of the spinal cord?
Conus Medullarise
Where is the cauda equine found?
the lumbar cistern of the subarachnoid space
What is the film terminal?
Filum terminale= continuation of pia mater (the structure which coats the spinal cord and spinal rootlets)
What is the name given to the dilated dural sac which ends at S2?
Dural cistern
Where is the white matter found in the spinal cord?
The H shaped central section of the spinal cord
What is grey matter made up of?
Neuron cell bodies
What is white matter made from?
Axons
What are nissl bodies?
Rough endoplasmic reticulum in the cell bodies of neurones
What are the meninges?
Meninges is made up of the coverings of the spinal cord and cerebrospinal fluid
Name the three coverings of the spinal cord
- Dura mater
- Arachnoid (avascular)
- Pia mater (vascular)
Where is the subarachnoid space?
In between the Pia mater and arachnoid mater
What is contained within the subarachnoid space?
cerebrospinal fluid
Name the structure that suspends the spinal cord within the subarachnoid space
denticulate ligament
What does the denticulate ligament extend from?
The Pia mater
What attaches the coccyx and the bottom part of the vertebral column?
The phylum terminali
At what level is sympathetic outflow from the spinal cord found?
thoracolumbar outflow at T1-L2
Where do the cell bodies of sympathetic nerves originate?
The lateral horn o the spinal cord
At which levels are parasympathetic outflow from the spinal cord found?
The parasympathetic nerves leave the spine at the craniosacral outflows (cranial outflow from the brain and sacral outflow from the pelvic splanchnic)
Name the two arteries that supply the spinal cord
spinal and segmental medullary arteries
What are the physical symptoms associated with spinal cord ischemia
muscle weakness and paralysis
Blood leaves the spinal cord via ________ ________ ________ _________. Which then drains to _________ ________ __________ _________.
Blood leaves the spinal cord via the Internal vertebral venous plexuses. Which then drains to the cerebral dural venous sinuses .
Where are lumbar punctures taken from in ADULTS and why?
Lumbar punctures are taken at L3-L4 or L4- L5 (remember that the spinal cord ends at L2 so the lumbar puncture cannot injure the spinal cord the needle must reach the subarachnoid space which is filed with CSF).
What are lumbar punctures used for?
Lumbar punctures are used to administer epidural anaesthesia into the epidural space or to collect CSF for testing (can be used to detect haemorrhage and meningitis)
Which regions of the spinal cord contain a lateral horn?
T1-L2/3 vertebrae (thoracolumbar outflow).
What is contained within the lateral horn of the spinal cord
cell bodies of the sympathetic neurons
In terms of ganglia, how do the sympathetic and parasympathetic differ?
The autonomic system (sympathetic and parasympathetic) has an extra ganglion compared to the somatic nervous system.
Why do autonomic nerves have an extra ganglion compared to the somatic nervous system
The extra ganglion is designed to help spread the autonomic signal more widely.
Some parasympathetic nerves originate in L2/L3 but there is not parasympatheic outflow until S2-4. How does this happen?
Some parasympathetic nerves originating in the lateral horn of the spinal cord at L2/3, travel down the vertebral column (in the cauda equina) and emerge between vertebrae S2-4! (remember that the spinal cord ends at L1-2).
Are sacral nerves 2-4 sympathetic or parasympathetic?
Parasympathetic
where in the spinal cord can you find sympathetic ganglion chain?
T1-L2.
Which root of the spinal cord are the sympathetic ganglion chain attached to?
ventral root
explain the three possible pathways that a sympathetic nerve signal can take after leaving the spinal cord via the ventral route
I) Re-enters the spinal nerve via the grey ramus communicans as postganlionic fibres and is distributed in both dorsal and ventral rami of the spinal nerve.
II) Distributed to the next ganglion up/down the sympathetic chain and leaves the sympathetic ganglion via the grey ramus communicans
III) Distributed to a distant ganglion further up/down the chain and leaves the sympathetic ganglion via the grey ramus communicans
How do sympathetic nerves supply the whole body when the outflow is only between T1-L2
The nerve impulses can move up and down the sympathetic ganglion chain which spans the whole spinal cord even though the sympathetic outflow only comes from T1-L2
Describe the sympathetic innervation of the face with regards to outflow and ganglia.
Sympathetic fibres leave the spinal cord at T1-L2/3 move up the ganglionic chain and synapse at the superior, middle and inferior ganglia (located at the cranial end of the ganglionic chain). These sympathetic nerves then supply the face and neck
What happens if the sympathetic nerves which supply the face become stretched or damaged?
If these sympathetic nerves become damaged or stretched, a triad of symptoms (called Horner’s syndrome) may be seen.
List the three symptoms included in Horner’s syndrome
- Partial Ptosis (drooping of the upper eyelid)
- Miosis (constriction of the pupil
- Anhydrosis (decreased sweating)
Is there a sensory aspect to the ANS?
Yes
What are the sensory receptors of the autonomic nervous system called?
Nociceptors
Where in the spinal cord do parasympathetic fibres arise?
Parasympathetic nerve fibres arise from the spinal cord at cranial and sacral levels (S2, S3, and S4 and the 3rd, 7th, 9th and 10th (10th = vagus) cranial
- Bilaterally, preganglionic axons run through the lumbosacral plexus to the _______ _________.
Bilaterally, preganglionic axons run through the lumbosacral plexus to the sacral foramina.
