neuroanatomy Flashcards
spinal nerves?
C1 will emerge from above C1 vertebrae
C8 will emerge BELOW C7 vertebrae
This continues all the way down :)
Anterior and ventral are same thing
Posterior and dorsal are same thing
what other modality will be present?
Remember this is thoracolumbar outflow - so you will also have sympathetic outflow
spinal nerve modalities?
Spinal nerve = somatic sensory, motor + sympathetic
- Visceral afferents travel alongside sympathetic nerves but ARE NOT part of the spinal nerve
diaphragm motor supply?
phrenic nerve C3, 4, 5
dermatome landmarks?
upper limb?
nipple = T4
umbilicus = T10
upper limb = C5-T1
B - T6
nerve plexuses?
e.g.?
Intertwined anterior rami from a number of adjacent nerves - NOT posterior rami
e.g.
- cervical plexus (C1-C4)
- posterior scalp, neck + diaphragm
- brachial plexus (C5-T1)
- upper limb
- lumbar plexus (L1-L4)
- lower limb
- lumbosacral plexus (L5-S4)
- lower limb, gluteal region, perineum
…
horner syndrome s/s?
Ax?
Symptoms: miosis, ptosis, reduced sweating (anhydrosis), increased warmth and redness
Ax = compression of cervical sympathetic trunk:
- Root of neck trauma
- Carotid dissection
- Internal jugular vein engorgement
- Deep cervical node metastases
- Pancoast tumour (lung apex)
how many vertebrae?
spinal nerves?
enlargements?
vertebrae = 33
spinal nerves = 31
2 enalrgements = cervical + lumbar
conus medullaris?
what comes after?
termination of spinal cord - L2
continues as connective tissue called filum terminale
*anchors spinal cord to coccyx
spinal meninges continuous with?
what are they?
Spinal meninges are continuous with cranial meninges via foramen magnum
- Dura mater
- Arachnoid mater
- Pia mater
spinal cord suspended in canal via?
made of?
subarachnoid space filled with?
denticulate ligment - found laterally
made from pia + arachnoid mater
subarachnoid space filled with CSF
…
central canal of spinal cord?
difference between posterior horn + anterior horn anatomically?
Central canal of spinal cord opens into 4th ventricle superiorly
- Posterior horn extends all the way up to the surface of the spinal cord
- The ventral horn does not
- Just helps with orientation :)
spinal segments T1 to L2 spinal cord?
arterial supply spinal cord?
3 major longitudinal arteries
- 1 anterior
- 2 posterior
- Originate from vertebral arteries and run the entire length of spinal cord
Segmental arteries
- Derived from vertebral, intercostal and lumbar arteries
Radicular arteries
- Travel along dorsal and ventral roots
greater anterior segmental medullary artery?
Adamkowitz - larger
derived from 9th-12th intercostal artery
venous drainage of spine?
where is somatosensory cortex located
post-central gyrus
what happens as you descend cord?
ascending = sensory
descending = motor
dorsal column/medial lemniscus tract function?
where do fibres cross?
Fine touch and conscious proprioception
Fibres cross in medulla
DCML pathway found?
explain pathway
found dorsally (posteriorly) in cord
pathway:
first neurons synapse in medulla
- Nucleus gracillis - receives info from lower body
- Nucleus cuneatus - upper portion of body
2nd neurons CROSS MIDLINE in MEDULLA (right side of brain controls left side and vice versa)
- Passes through medial lemniscus (pons) to thalamus where it synapses
3rd neuron then travels to cortex (primary somatosensory cortex) i.e. postcentral gyrus
So 3 neurons between e.g your fingertip and primary somatosensory cortex
…
spinothalamic tract found?
Function?
spinothalamic tract found anteriorly (ventrally) in cord
Carries pain + temperature - skips medullary synapse
explain spinothalamic tract pathway
fibres do not synapse in medulla
first synapse is in posterior horn
- cross midline
- 2nd neurons climb spinal cord in anterolateral column
pass through spinal lemniscus in midbrain
synapse in thalamus
3rd neuron then travels to somatosensory cortex
…
where is motor cortex found?
pre-central gyrus
descending tracts?
corticospinal
vestibulospinal
rubrospinal
reticulospinal
tectospinal
corticospinal tract found?
function?
other name?
laterally in spinal cord
fine precise movement e.g. digits
called pyramidal tract as it forms medullary pyramids
explain corticospinal tract pathway
Travel from pre-central gyrus
cross at medulla - forms pyramids on anterior surface of medulla, so called pyramidial tract
- Crossed fibres (85%) form the lateral corticospinal tract
- Uncrossed fibres (15%) form the ventral corticospinal tract
crossed fibres = decussation of the pyramids
Ventral fibres cross at vertebral level they are going to exit at
CVA fof internal capsule?
extrapyramidal tracts?
tectospinal, reticulospinal, rubrospinal, vestibulospinal
tecctospinal tract function?
explain pathway
Input mostly to cervical segments - controls head and neck movement due to visual stimuli i.e. head turns after loud noise
- Begins in midbrain (posterior - tectum)
- Projects across midline in midbrain
- travels down into spinal cord
- Innervates cervical portions of spinal cord
reticulospinal tract?
fibres originate?
Forms central core of brainstem - receives input from virtually all parts of CNS
- Has many functions including influencing voluntary movement
Fibres originate from reticular formation in pons and medulla
vestibulospinal tract?
pathway?
ipsilateral tract - controls own side of body
- begins at pons in vestibular nuclei
- input into “antigravity” extensor muscles - back, neck, legs
- i.e. stops you falling when shoved
so when you are shoved, input does not need to go to cortex
descending tracts
Brown sequard syndrome?
cerebellar lobes?
anterior
posterior
flocculonodular lobe
cerebellum sits in posterior cranial fossa
how is cerebellum attached to brainstem?
via 3 stalks called peduncles
…
does cerebellum have sucli and gyri?
grey and white matter?
called folia and sulci :)
like cerebrum, has outer grey matter and inner core of white matter
layers of cerebellum?
molecular layer (outer)
purkinje cell layer (middle) - these are output cells
granule cell layer (inner)
afferent info to cerebellum?
efferent projections?
Afferent projections to cerebellum (inputs)
- Spinal cord (somatic proprioceptors and pressure receptors)
- Cerebral cortex (via pons)
- Vestibular apparatus via vestibular nuclei
- (Enter via cerebellar peduncles)
Efferent projections (outputs)
- Purkinje cells
- (project across midline and synapse in thalamus –> motor cortex)
functonal divisions cerebellum
Floccular nodular node = vestibular cerebellum
- translates info from vestibular nuclei
- E.g. shove (anti-gravity)
Vermis = spinocerebellum
- controls automatic functions e.g. posture
Pontocerebellum = receives info from pons (whcih recieves info from cortex)
- voluntary movement e.g. playing piano
- Because cortex informs :)
..
bilateral cerebellar function?
functions of basal ganglia?
Facilitate purposeful movement
inhibit unwanted movement
Posture and muscle tone
basal ganglia names?
putamen continuous with?
caudate nucelus
putamen = potato
caudate = tadpole
location of basal ganglia axial
location of basal ganglia coronal
…
basal ganglia pathway damaged in Huntington’s?
Parkinson’s?
Chorea = indirect pathway damaged
Parkinson’s = direct pathway damaged
Indirect = inhibition
unilateral basal ganglia lesion?
what do these lesions cause?
affect contralateral side of body
cause:
- Changes in muscle tone
- Dyskinesias
- Tremor
- Chorea
- Myoclonus
remember lump of pons is anterior
cant see trochlear because it exits posteriorly
nerves found at pontomedullary junction?
6, 7, 8
do all cranial nerves exit anteriorly?
yes except trochlear whcih exits posteriorly
(vestibulocohlear also exits laterally)
function cranial nerves?
provide sensation and motor to the head
Except CN X which is “the wanderer”
what is the only nerve that does not synapse in thalamus prior to reaching cortex?
modality?
olfactory nerve - CN 1
modality = purely sensory
where is primary olfactory area?
posterior frontal lobe, extends into temporal lobe
….
pons anterior aspect?
posterior aspect?
anterior = bulge
posterior = 4th ventricle
where does CN 3 exit?
4?
5?
3 = midbrain
4 = midbrain
5 = pons
where is occulomotor nucleus found?
occulomotor nerve function?
Occulomotor nerve pathway
occulomotor + EWN found in superior colliculus
function = moves eye via somatic motor + controls pupil via parasympathetics (EWN)
where is trochlear nucleus found?
function?
infiror colliculus
function = superior oblique (down+out)
abducens nucleus found?
in the pons
hypoglossal nucelus found?
found in upper medulla
…
spinal accessory nerve function?
pathway?
function = innervates trapezius and sternocleidomastoid
- Emerges from spinal cord C1-C5
- turns back and enters foramen magnum
- then exits through jugular foramen
mixed cranial nerves?
5, 7, 9, 10
trigeminal nerve function?
Somatosensation of face
Proprioception associated with chewing (TMJ, muscles of mastication, teeth)
Motor control: muscles of mastication, tensor tympani, mylohyoid, anterior belly of digastric, tensor veli palatini
trigeminal nerve nuceli
what happens once reached nucleus?
midbrain = mecencephalic nucleus
- proprioception (shewing)
pons = pontine trigeminal nucleus (principal nucleus)
- sensory face
spinal cord = spinal nucleus
- pain and temp face
nuclei will project to the thalamus then primary somatosensory cortex
lesion of spinal nucleus?
depending on where lesion is - can get oral sparing (i.e. retain pain and temporature around oral cavity)
cranial nerve VII function?
Motor to muscles of facial expression, stapedius
Parasymp - pterygopalatine, submandibular ganglia
Taste - anterior ⅔ of tongue
CN IX function?
sensation, pain, temperature sense from posterior tongue, pharyngotympanic tube + upper pharynx
Taste (post ⅓)
Parasymp to otic ganglion (parotid gland)
Motor (one muscle - stylopharyngeus)
vagus nerve function?
sensation, pain, temperature to pharynx, larynx, trachea, oesophagus, and thoracic + abdominal viscera
Taste (epiglottis)
Parasymp to thoracic and abdominal viscera
Motor to pharynx and larynx
facial nerve nuclei?
- Motor - facial motor nucleus
- Salivatory nucleus - salivation (submandibular ganglion) + lacrimation (pretygopalatine ganglion)
- Solitary nucleus - taste
- Spinal nucleus of trigeminal nerve - ear canal (very small area of sensation)
geniculate ganglion?
provide taste to anterior ⅔ of tongue (CN VII)
glossopharyngeal nuclei?
- Solitary nucleus - taste
- Spinal nucleus - just like facial (small area around ear)
- Salivatory nucleus - parasympathetic to parotid gland
- Nucleus ambiguus - voluntary controls 1 single muscle (stylopharyngeus)
- Supplies 9th and 10th CN
vagus nerve nuclei?
- Dorsal nucleus - parasympathetic outflow
- Lungs, heart, gut etc
- Solitary nucleus - taste (epiglottis)
- Spinal trigeminal nucleus - thing about ear again
- Nucleus ambiguus - muscle control of larynx and pharynx
summary of CN nuclei
solitary nucleus structure + function
motor input to cranial nerves?
corticobulbar tract (related to corticospinal tract)
