Brain and spinal cord - Week 1 Wet Room Flashcards
what are the 3 parts of the brain stem form superior to inferior?
midbrain
PONS
medulla
which cranial fossa does the brainstem lie?
posterior cranial fossa
which 2 vesicles of the neural tube gives rise to the brainstem embryologically?
mesencephalon (midbrin)
rhombencephalon (hindbrain)
what are the cavities (of the ventricular system) that lie within the brainstem?
IV ventricle
cerebral aqueduct
what is the groove that seperates the PONS from the medulla?
pontomedullar junction
which cranial nerves can you see emerging from the pontomedullary junction?
CN VI - abducens nerve
CN VII - facial nerve
CN VIII - vestibulocochlear nerve
which cranial nerve that emerges from the pontomedullary junction has the longest intracranial course?
abducens nerve
the long intracranial nerve course of the abducens nerve makes it vulnerable to injury by increased intracranial pressure or other mechanical factors such as intracranial fractures of cerebral artery aneurysms
what would be the consequence of this nerve being injured?
cant abduct eye
can be misleading clinical presentation and is hence called as a false localising sign
what is the following strucutres of the medulla made of:
pyramids
decussation of the pyramids
olive
pyramids - main tract for motor fibres
decussation of the pyramids - fibres crossing form one side to snother (motor)
olive - involved in motor function
posteriorly on the medulla, there are parts of the medulla known as the open and closed part and which is superior and inferior?
open - superior
closed - inferior
what does the open part of the medulla open onto?
IV ventricle
through which foramen doed the medulla pass to become the spinal cord?
foramen magnum
on the surface of the PONS there is the origin of the trigeminal nerve and also the middle cerebral peducle which is made up of what?
crossed afferent fibres - fibres going back and forth form the midbrain to the cerebellum
centripetal fibres - i.e. incoming fibers
what is immediatley superior to the midbrain and what is inferior?
hpyothalamus
PONS
what kind of fibres make up the cerebral peduncles and where are they destined for?
motor fibres
rest of the body
what are surface features of the midbrain?
cerebral peduncles
superior nd inferior colliculi
what is the superior and inferior colliculi inolved in?
superior - visual reflexes
inferior- audiation/hearing, acts as the channel for almost all auditory signals in the human body
what make sup the dienchephalon?
thalamus and hypothalamus
what are the surface projections of the hypothalamus called?
optic chiasm
pituitary stalks
mammilary bodies (The mammillary bodies are a pair of small round bodies, located on the undersurface of the brain that, as part of the diencephalon, form part of the limbic system)
what is the pineal gland?
A small endocrine gland in the brain of most vertebrates. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles
just baove the colliculi
what is the name given to the midline structures connecting the 2 cerebellar hemispheres?
vermis
what are the lobes of the cerebellum?
what are the names of the cerebellar peduncles?
superior
middle
inferior
what is the name of the ventricular psace that lies immediatley anterior to the cerebellum?
fourth ventricle
name the cranial fossa that the cerebellum is in contact with
posterior cranial fossa
identify the foramen in the skull that the cerebellum sits above?
foramen magnum
what part of the cerebellum sits atop the foramen magnum?
and what may happen to it is there is a sudden drop of intracranial pressure?
cerebellar tonsils
the tonsils may herniate through the foramen magnum causing cerebellar coning
what is the name of the large fissure separating the two cerebral hemispheres
longitudinal fissures
The corpus callosum is a large, C-shaped nerve fiber bundle found beneath the cerebral cortex. It stretches across the midline of the brain, connecting the left and right cerebral hemispheres. It makes up the largest collection of white matter tissue found in the brain. What type of fibres are most likely to be carried in the corpus callosum?
commissural fibres
the cerebral hemispheres sit on the floor of the anterior and middle cranial fossa however posteriorly, the cerebral heispheres sit on what?
the tentorium cerebelli which is a fold of the dura mater which covers over the cerebellum
what lobe contains the primary motor cortex?
forntal lobe - pre-central gyrus
what lobe contains the primary visual cortex?
occipital lobe - calcarine sulcus
what lobe contains the primary sensory cortex?
parietal lobe - post-central gyrus
what lobe contains the primary auditory cortex?
temporal lobe - superior temporal gyrus
what part of a vertebrae can be removed to open up the spinal cord?
lamina
what muscle overlies the lamina
deep erector spinae
what ligament may be encountered in the process of opening the spinal cord?
ligamentum flavum
what other structures apart from the spinal cord and the meninges lie in the spinal canal?
vertebral venous plexus
fat
anterior and posterior spinal arteries
at what level does the spinal cord terminate in:
adults
newborns
adults - L1 - L2
newborn - L3
at what vertebral level do the flowwoing terminate:
dura mater
atachmoid mater
dura mater - S2
arachmoid mater - S2
what is the dural sac?
dural sac is the membranous sheath (theca) or tube of dura mater that surrounds the spinal cord and the cauda equina
terminates caudally at S2
what happens to the pia mater inferior to the spinal cord?
conus medullaris is the tapered, lower end of the spinal cord. It occurs near lumbar vertebral levels 1 (L1) and 2 (L2), occasionally lower
forms the filum terminale that attaches to the coccyx
what occupies the space between the end of the spinal cord and the termination of the dura and arachnoid?
and what is the clinical significance of this?
CSF
cauda equina
filum terminale
can do a lumbar puncture
what is the cauda equina?
The cauda equina (from Latin horse’s tail) is a bundle of spinal nerves and spinal nerve rootlets, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enlargement and the conus medullaris of the spinal cord
at hwat verebral level would you perform a lumbar puncture on an adult?
L3/4 or L4/5
how would you positionn the patient to gain access to the lumbar cistern and why?
lying on your side with knees flexed towards chest
how many pairs of psinal nerves are there
31 pairs
clinicians refer to lesions of the spinal nerves after they leave the cord as lower motor neurone lesions. what are upper motor neurone lesions and where are they loctaed?
UMN is brain and spinal cord and LMN is nerves startinf in the ventral horn and coming out
in general terms UMN are characterised by spasticity, increased muscle tone and complex sensory syndromes whereas LMN conditions are characterised by global sensory changes and/or flacis paralysis depending on the nature of the mixed peripheral nerves
is damage to the cauda equina classified as an upper or lower motoe neurone lesion?
LMNL
