week 1 Spinal cord and spinal pathway Flashcards
how many cervical verterbrae?
7
how many thoracic verterbrae?
12
how many lumbar verterbrae?
5
how many sacral verterbrae?
5
how many cocygeal verterbrae?
1-4
how many cervical spinal nerves are there?
- 1 more than the amount of cervical verterbrae
where does the phrenic nerve arise from?
C3,4,5
where does the 1st cervical nerve run?
below the base of the skull and above the the 1st cervical vertebrea
do all spinal nerves run above there corresponding verterbrea?
no only cervical vertebrae 1-7 do
At what point do the spinal nerve run below there corresponding verterbea?
from C8 as that runs over T1 vertebrea. Therefore T1 spinal nerve is underneath T1 vertebrea. Undreneath the pedicles
where exactly does spinal nerve C2 to C7 arise?
above the corresponding pedicle. So C2 spinal nerve above pedical of C2 vertebrea
What occurs at C8?
transition in nomeclatures of nerves?
On the spinal column there is two enlargements where?
Cervical and lumbar enlargments
why are there enlargments at the cervical and lumbar region?
Brachial plexus form at the cervical
Sciatic nerves form at the lumbar region.
Need to be enlarged as more and larger nerves are being formed
what type of information does dorsal rootlets contain?
sensory
what type of information does sensory rootlets contain?
motor
what is the name of the tip of the spinal column?
conus medullaris
at what verterbral level is the tip of spinal column? (conus medullaris )
L1/L2
what is Cauda equina?
bundle of rootlets that carry on from the conus medullaris.
what is Filum terminale?
fine thread of pia matter–> remnant of the spinal cord
is the dura matter one layer or double in the spinal cord?
there is no periosteal layer just a meningeal layer
describe the structure of the dura matter?
Tough, fibrous “sleeve”, separated from bone by fat-filled epidural (extra) space
- Only one layer, unlike double layer around brain
describe the structure of the Arachnoid mater
Thin, delicate layer pressed against dura by CSF
describte the structure of Pia matter?
Thin layer attached to surface of cord
Forms flat denticulate ligaments
how does CSF surround the spinal cord?
CSF enters subarachnoid space around cord by leaving the apertures of the ventricular system – lateral and median
what happens to the periosteal layer surrounding the brain?
it becomes the periosteum of the skull
what does subdural space seperate?
arachanoid matter and dura matter
what are denticulate ligament ?
they are extensions of the pia matter laterally that attach to the vetebral canal for stability and prevents rotation of the spinal cord.
Blend with the arachanoid matter
what do dorsal root ganglion contain?
primary sensory fibres–> long axon to the ganglion then short to the CNS
what is the relationship between the dura matter and the ventral/dorsal rootlets?
they do not pierce the dura but become covered by the dura for protection
does epidural pass through the dura?
no it does not specific to that spinal root
does spinal pierce through the dura?
yes it does so can affect all the spinal nerves –> depending on the patients position depends where in the spinal colunmn is affected
what does Cauda equina contain?
Dorsal and ventral roots of lower lumbar, sacral and coccygeal segmental spinal nerves
where is lumbar puncture done?
at the cauda equina –> withdraw CSF
why is it safe to do lumbar puncture at the cauda equina?
there is no spinal cord there
when a fetus what is the relationship of the spinal cord to the verterbal column?
the spinal cord runs along the primitive vertebral column
how does the positioning of the spinal cord to the verterbal column change with time?
verterbral column grow faster than spinal column and also you straighten up so at birth the spinal cord is shorter than the vertebral column –> level L3 –> at adult hood goes to L1/2
what is the vasculature of the spinal cord?
The spinal cord receives arterial blood via the unpaired anterior and paired posterior spinal arteries These typically arise from the vertebral arteries.
what are vertebral arteries supported by when supplying the spina cord?
supported by segmental medullary and radicular arteries along the length of the cord.
what are the different locations in which spinal arterial branches come off?
vertebral (neck), posterior intercostal (thorax), lumbar (abdomen) or lateral sacral (pelvis).
what does white matter contain in spinal cord?
contains tracts, long pathway, axons , up or down spinal cord–> they are myelinated
what does grey matter contain in spinal cord?
Cell bodies–> connected to ascending and descending fibers
is white matter or grey matter myelinated?
white matter
where does the pelvic splenic nerves arise from?
S2,3,4
in a transverse section of spinal cord what is the positioning of the white and grey matter?
white is around the edges and grey in the centre
what does grey matter contain throughout the spinal cord?
dorsal grey horn –> sensory
ventral grey horn –> motor
where is lateral grey horn present and what does it contan?
(T1-L2) where the sympathetic chain is formed
(S2-S4) where pelvic splenic nerves form
formation of the autonomic nerves
what is the route of visceral motor ( para or sympathetic)
via the ventral rootlet as it is going to the organ/body to do something
where does sensroy fibers from the lower limbs run through?
Gracile fascicle medially
where does sensory fibers from the upper limbs run through?
Cuneate fascicle laterally
above what level do you see 2 dorsal columns in the spinal cord?
above T6
when does dura terminate?
S2
At what level is the cordina equina?
L1/2
what is the route of filum terminale
The filum terminale a continuation of the pia mater from the conus medullaris of the spinal cord and is joined by the arachnoid and dura mater at the level of S2 and continues inferiorly through the sacrum as the coccygeal ligament to its attachment at the coccyx.
what is lumbar puncture used for?
Meningitis Ms Diabetes Encephalitis Subarachnoid haemorrhage Tumor
See if blood is in the CSF
test for protein in CSF
what happens if there is protein in CSF?
increase of water in CSF and therefore increase in pressure
At what level do you do lumba puncture?
L4/5
Where do the rootlets in the cauda equina end up?
These are the dorsal and ventral nerve roots going to the corresponding intervertebral foramen
What is the Lumbar Cistern?
Inferior limit of the vertebral canal
Extends from the terminal of spinal cord –>L1/2
To the termination of the dural sac –>approx. S2
What is contained within the Lumbar Cistern?
CSF
Continuation inferiorly of the pia matter –> Filum terminale
Dorsal and Ventral roots running down from the appropriate spinal cord segment to the appropriate intervertebral foramina
Collection of nerve rootlets is cauda equine
What is the clinical importance of Lumbar Cistern?
Important space to administer anaesthetic for spinal bloc or retrieve CSF for testing e.g. for meningitis
What is the roots of tibial nerve?
Anterior division of sciatic nerve L4-S3
What is the nerve roots of common fibular nerve?
Posterior division of sciatic nerve L4-S2
What is the nerve roots of deep fibular nerve?
L5-S2
What is the nerve roots of superfecial fibular nerve?
L4-S1
What muscles make up the superfecial intrinsic muscles of the back?
Splenius capitis
Splenius Cervicis
What is the action of the superfecial intrinsic muscles of the back? Also are they supplied by the dorsal or anterior rami of the cervical spinal nerves?
Bilaterally –> extend the head and nack
Unilaterally –> lateral rotation and flexion of the head and neck to the ipsilateral side
Dorsal rami
Splenius Capitis –> C2-6
Splenius Cervicis –> lower cervical spinal nerves
The intermediate intrinsic muscle of the back is comprised of what muscle?
The large erector spinae
What is the position of the large erector spinae and what is its action?
It is the chief extensor of the vertebral column.
It is on either side of the column
What muscles make up the erector spinae from medial to lateral?
Spinialis
Longissimus
iliocostalis
What are the deep intrinsic muscles of the back?
Group of small muscles deep to erector spinae that originate from the transverse proces of vertebrae and insert onto a spinous process of a superior vertebrea.
Collectively known as Transversospinalis group
What 3 muscles make up the transversospinalis group?
Semispinalis
Multifidis
Rotares
What is the Cauda equine?
This is a bundle of lumbar, sacral and coccygeal nerve roots at the tip of the spinal cord
At what level doe the dura matter terminate?
S2
What are the 7 layers you have to pierce in lumbar puncture?
1) Supraspinous ligament 2) Interspinous ligament 3) Ligamentum flavum 4) Epidural space 5) Dura mater 6) Arachnoid mater 7) Subarachnoid space
Where is epidural inserted into?
The epidural, it does not enter the dura matter
Where is CSF withdran?
The lumbar cistern, the nerve rootlets move out of the way as you do the lumbar puncture procedure
What is the lumbar cistern?
It extends from the end of the spinal cord at the conus medullaris (L1/2) to S2. It contains CSF, Filum terminalis and the nerve rootlets of the cauda equina.
What is the relationship between the spinal cord and vertebral column of a featus at 2-3 months.
They are roughly the same length
What branches do the spinal branches come off at dfferent locations of the body?
Vertebral is the neck
Posterior intercostal is the thorax
Lumbar is the abdomen
Lateral scaral is the pelvis
In the doorsal root is the somatic and vsiceral sensory fibers made up of 1 or multipel of fibers
They are the same and come from the dorsal grey horn
The ventral root contains vicersal and somatic motor fibers. Is the part of one fiber or more?
They are two seperate fibers
The visceral motor comes from the lateral grey horn
While the somatic motor fiber comes from the ventral grey horn
What is the outer protective layer as the spinal nerve leaves the vertebral canal?
As each spinal nerve leaves the vertebral canal it takes with it a meningeal covering.
This goes on to form the epineurim which is a protective out sheath of connective tissue
Is there most white matter during ascending or descending part of the spinal cord?
Increase as you ascend the spinal cord
At what points do the ventral grey horn enarlage?
They enlarge at the cervical and lumbosacral plexus due to the increase amount of motor fibers compared to the intercostal and abdominal nerves
Why do the ventral grey horn enlarge at certain points?
It is where motor fibers meet limbs
What fasicle of the dorsal column would you see below T6?
Gracile fasicle
Describe how the grey matter is regionally specialised?
The grey matter is divided into regions called laminae These are the sights of sensory or motor nuclei.
They each extend a varying length of the cord
Certain functions in the body relate to certain lamina
Where do the dorsal and ventral roots unite to form the spinal nerves?
Level of the Intervertebral foramen
What do the dorsal and ventral rami of the spinal nerve innervate?
They both contain mix fibers.
Dorsal rami is the smaller of the two and supplies the back muscles
Ventral rami much larger and supplies the rest of the body except for the head. Supplies the brachial and lumbasacral plexus.
What is the inferior and superior border of the subarachanoid space?
Superior: Superior sagital sinus
Inferior: Tip of lumbar cistern at S2 level
What is the inferior and superior border of the epidural space?
Superior: Foramen magnum
Inferior: Sacral hiatus–> S4
What surface landmarks do you use for lumbar puncture and why is the patient curled up?
Use the landmark of the spinous process and Supracristal plane to identify the L4 and L5.
The patient is curled up to increase the gap between the Spinous process
Explain the route from the posterior intecostal artery to the spinal artery?
Posterior intercostal artery to the spinal branch to anterior and posterior segmental medular artery or radicular artery to the unpaired anterior and paired posterior artery.
