Neuroanatomy 2 Flashcards
when does the spinal canal end?
L1-L2
why do we take CSF from L4 level?
the spinal cord has ended so there is low risk of damaging it
the region where the spinal cord terminates is called the …
conus medullaris
what is the very end section of the spinal canal (NB not cord) called?
filum terminale
what keeps the spinal cord in place in the spinal canal?
denticulate ligament (looks like teeth)
the inner part of the spinal cord is made up of __ matter
grey
the outer part of the spinal cord is made up of __ matter
white
what is located in the centre of the spinal cord?
central canal
when looking at a cross section of a spinal cord, how can you tell which side is posterior?
the part where the 2 horns of the grey matter meet the surface is posterior
when discussing the spinal cord, anterior can also be called ___
ventral (think Av)
which spinal segments contain a lateral horn and why?
T1-L2
contain the preganglionic sympathetic neurons (thoracolumbar)
how many longitudinal arteries supply the spinal cord?
3 (1 anterior, 2 posterior)
aside from the longitudinal arteries, which other arteries supply the spinal cord?
segmental and radicular arteries
segmental arteries are derived from?
vertebral, intercostal and lumbar arteries
where do radicular arteries exist?
around the dorsal and ventral roots (radicular means root)
venous drainage of the spinal cord is similar to that of the arterial supply T or F
T
what is the epidural space?
the space between the dura and the bone in the spinal cord (epidural is given here)
where do sensory neurons go to?
the primary somatosensory cortex in the postcentral gyrus
define ganglion
group of cell bodies located outwith the CNS
where does the PNS begin?
spinal rootlets
the anterior cerebral artery runs along the __ fissure
longitudinal
why do some regions of the spinal cord have more grey matter than others?
more dermatomes to reach/longer route to travel eg for an arm will require more grey matter
which pathway is in charge of sensation for fine touch and proprioception?
the dorsal column/medial lemniscus pathway
what is a lemniscus?
band of white matter that travels up the spinal cord
where do the fibres in the DCML pathway cross?
medulla oblongata
sensory fibres from the LHS will be transmitted to the …. of the brain
RHS
name the 2 synapse points in the DCML pathway
- medulla
2. thalamus
where is the end point of the DCML pathway?
postcentral gyrus
what does the spinothalamic tract control?
transmits sensory fibres for pain, temperature and deep pressure to the brain
where do the spinothalamic tract fibres cross?
segmentally (switches sides) at the very start in the same area of the spinal cord as it originated
what sensory pathway transmits pain fibres?
spinothalamic tract
where do the fibres of the spinothalamic tract synapse?
thalamus
where is the primary motor cortex located?
precentral gyrus
main motor tract of the body
corticospinal tract
where does the corticospinal tract start and end
precentral gyrus to spinal cord
what does the corticospinal tract control?
fine, precise movement of distal limb muscles
why is the corticospinal tract also called the pyramidal tract?
forms visible ridges that look like pyramids on the anterior surface of the medulla
where does the corticospinal tract’s fibres cross?
medulla around the foramen magnum
all fibres of the CS tract cross at the medulla T or F
F, a few cross segmentally at a certain spinal level
crossed fibres of the CS tract are referred to as…
lateral CST
uncrossed fibres of the CS tract are referred to as…
ventral CST
what would happen clinically if a CVA occurred in the CS tract?
patient would have spastic paralysis with hyperflexion of the upper limbs
what does the tectospinal tract control?
MOTOR function (mainly visual and auditory) to cervical segments reflex function to head and neck
where does the tectospinal cord start and end?
tectum (roof of midbrain) to spinal cord
define the reticular formation
series of interconnected nuclei in the brainstem that carry out automatic functions in the body eg breathing
what motor functions does the reticulospinal tract control?
voluntary movement eg walking
fibres originating in the pons facilitate __ movements
extensor
fibres originating in the medulla facilitate __ movements
flexor
what tract is in charge of regaining your balance after a trip?
vestibulospinal tract
main function of the vestibulospinal tract?
excitatory input to antigravity extensor muscles
where does the vestibulospinal tract start and end?
vestibular nuclei of the pons and medulla to the spinal cord
a lesion where would have a severe impact on the vestibulospinal tract?
midbrain
if the vestibulospinal tract didnt work what would happen to muscle tone?
extensor muscle tone would overreact and the patient would become spastic
a lesion in the corticospinal tract at RHS spinal cord level will cause loss of function in what side?
RHS as fibres have already crossed at the brain
