Neurology- anatomy Flashcards
Trace a drop of CSF to the subarachnoid space
:Produced by the ependymal cells of the choroid plexus
- lateral ventricles thru foramen of monroe to the 3rd ventricle
- 3rd ventricle thru cerebral aqueduct to the 4th ventricles
- 4th ventricle thru either lateral foramen of luschka or medial foramen of magendie to subarachnoid space
- subarachnoid space thru arachnoid granulations into dural sinuses
Describe the dural venous drainage
- superior sagital sinus
- the great vein of galen joins the inferior sagital sinus resulting in the straight sinus
- straight sinus + superior sagital sinus + occipital sinus join at the confluence of sinuses
- confluence of sinuses gives rise to the transverse sinuses –> sigmoid sinus –> internal jugular vein
Contents of cavernous sinus
: located on either side of the pituitary; collects blood from superficial cortex and eye and drains into the superior pertrosal sinus –> sigmoid sinus –> internal jugular
-contains branch of internal carotid a., CN III, IV, V1, V2, VI & post ganglionic sympathetic en route to orbit
Patient: Opthalmoplegia, decreased corneal and maxillary sensation with normal visual acuity
Cavernous sinus syndrome: usually due to mass effect, fistula, thrombosis
- CN VI most commonly affected
Recall: opthalmoplegia means weakness or paralysis of EOM
Anterior circulation of the brain
:result of the internal carotid; includes the ACA and MCA
- on the left ICA is a branch from the aortic arch
- on the right ICA is a branch off the brachiocephalic a.
Anterior cerebral artery
:ACA; supplies anteromedial surface of frontal and parietal lobe
-Lesion: contralateral paralysis leg > arm & contralateral sensory loss leg > arm
Middle cerebral artery
:supplies lateral surface of temporal and parietal lobes, optic radiations
-Lesion: Motor= contralateral arm, face paralysis; Sensory = contralateral arm and face loss of sensation; Optic radiations: homonymous hemianopsia; Speech= produce Broca’s or Wernickes aphasia (dominant hemisphere usually left); Hemineglect= contralateral neglect (usually right sided lesion, resulting in neglect of the left side)
Lenticulostriate artery
:branch of the MCA, supplies the striatum & internal capsule
-Lesion: contralateral hemiparesis/hemiplegia (weakness)
-Most common location of lacunar infarcts secondary to unmanaged hypertension
Posterior Circulation of the brain
: result of the vertebral arteries
- vertebral arteries arise as branches of the subclavian artery’s
- give rise to ASA, basilar artery, PICA, AICA, SCA, PCA
Anterior spinal artery
:supplies the lateral CST, medial lemniscus, caudal medulla = CN XII
Medial medullary syndrome
: contralateral hemiparesis, decreased contralateral proprioception, ipsilateral hypoglossal dysfunction (tongue deviates ipsilaterally)
-caused by infarct of paramedian branches of ASA and vertebral arteries
Posterior inferior cerebellar artery
:PICA; supplies posterior inferior cerebellum & lateral medulla = vestibular nuclei, lateral spinothalamic tract, descending (spinal) trigeminal nucleus, nucleus ambiguus, sympathetic fibers, inferior cerebellar peduncle
Lateral medullary syndrome
vomiting,vertigo, nystagmus, decreased in pain & temp (protopathic) sensation from ipsilateral face and contralateral body, dysphagia, hoarseness, decreased gag reflex, ipsilateral horner sundrome, ataxia, dysmetria
Note: nucleus ambiguus effects are specific to PICA
Anterior inferior cerebellar artery
:AICA; supplies middle and inferior cerebellar peduncles & lateral pons= CN nuclei, vestibular nuclei, facial nucleus, spinal trigeminal nucleus, cochlear nuclei, sympathetic fibers
Lateral pontine syndrome
: vomiting, vertigo, nystagmus, paralysis of face, decreased lacrimation and salivation, decreased taste from anterior 2/3 of tongue, decreased corneal reflex. Face - decreased pain and temp (protopathic) sensation. Ipsilateral diminished hearing, ipsilateral horner syndrome, ataxia, dysmetria
Note: facial nucleus effects are specific to AICA lesions
Posterior cerebral artery
:PCA; supplies occipital cortex, visual cortex
Lesion to PCA
:contralateral hemianopia with macular sparing
Basilar artery
:supplies pons, medulla, lower midbrain, CST, CBT, ocular cranial nerve nuclei, PPRF
Locked in syndrome
lesion to the basilar artery = preserved consciousness and blinking, quadaplegia, loss of voluntary facial, mouth and tongue movements
Anterior communicating artery
:ACom
- most common lesion is saccular (berry) aneurysm which can lead to a stroke
- usually results in visual field defects
Posterior communicating artery
: common site of saccular aneurysm leading to CN III palsy = eye is down and out with ptosis and pupil dilation
Limbic system
Structures include: hippocampus, amygdala, fornix, mamillary bodies and cingulate gyrus
Function: emotion, long-term memory, olfaction, behavior modulation, and autonomic nervous system
-major output is to the hypothalamus to control ANS and neuroendocrine secretions
Input to the cerebellum
- Contralateral cortex via middle cerebellar peduncle
- Ipsilateral proprioceptive information via inferior cerebellar peduncle from spinal cord (input nerves = climbing fibers and mossy fibers)
Cerebellar output
- Sends information to contralateral cortex to modulate movement
- output nerves = purkinje cells -> deep nuclei of cerebellum -> contralateral cortex via superior cerebellar peduncle
