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Flashcards in Neuroanatomy - Firecracker Deck (26)
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1

Where are the different sinuses located? 

  • The superior sagittal sinus is located in the falx cerebri 
  • The confluence sinuses brings together the superior saggital sinus and straight sinus - branches into the transverse sinuses 
    • The transverse sinuses lie on the margins of the tentorium cerebelli 
    • The sigmoid sinus drains into the internal jugular vein

2

What clinical syndrome results from injury to the mammillary bodies? 

Wernicke-Korsakoff Syndrome - lesions to the anterior nucleus result in memory impairment. 

3

What is the distinguishing feature of a lateral pontine syndrome that indicates that the occlusion is in the anterior inferior cerebellar artery (AICA)?

Anterior inferior cerebellar artery (AICA) supplies the lateral pons and middle and inferior cerebellar peduncles

Cochlear nucles  - supplied by the AICA

Structures within the pons supplied by the pontine arteries and AICA:

  • Facial (CN VII) nerve and nucleus 
  • Vestibular nuclei (CN VIII)
  • Trigeminal (CN V) nuclei and nerve 
  • Spinal trigeminal tract 
  • Inferior and middle cerebellar peduncles 

Other structures within the pons supplied only by pontine arteries: 

  • Abducens (CN VI) nucleus and nerve
  • Corticospinal fibers
  • Medial lemniscus
  • Medial longitudinal fasiculus 

Occlusion of the AICA can result in lateral pontine syndrome: 

  • Ipsilateral facial paralysis 
  • Ipsilateral hearing loss due to ipsilateral cochlear nucleus damage 
  • Vestibular signs (e.g. vertigo, nystagmus) due to ipsilateral vestibular nucleus damage 
  • Ipsilateral loss of facial pain and temperature sensation 
  • Ipsilateral ataxia 

4

What arteries supply the circle of Willis?

The brain receives its blood supply from the carotid arteries and the vertebrobasilar system.

5

What are three possible sequelae of middle cerebral artery occlusion?

The MCA supplies the lateral portion of the cerebral hemisphere including Broca's area, Wernicke's area and motor sensory cortices of the contralateral trunk-arm-face

  • Lenticulostriate arteries are penetrating branches of the MCA supply the internal capsule and structures of the basal ganglia 
  • Very frequently involved in lacunar strokes 

Occlusion of the MCA can result in:

  • Paralysis/sensory loss of contralateral face and arm 
  • Broca's and Wernicke's aphasia 
  • Contralateral neglect syndrome

6

Where are the locations of the nuclei of cranial nerve 5? 

  • There are 4 primary nuclei within the trigeminal system: the main sensory nucleus, the spinal nucleus, the mesencephalic nucleus and the motor nucleus 
    • The mesencephalic nucleus ==> lateral portions of the midbrain and superior pons 
    • Main sensory nucleus ==> lateral pons, immediately caudal to the mesencephalic nucleus 
    • Motor nucleus ==> pons, medial to the main sensory nucelus 
    • Spinal nucleus ==> long collection of nerve bodies and fibers, begins at the junction of the pons and medulla, caudal to the main sensory nucleus, stretches to the level of C2 or C3 within the spinal cord. 

7

What are the arteries of the vertebrobasilar system? 

  • Subclavian arteries ==> vertebrobasilar system (vertebral arteries) which become the posterior cerebral arteries (PCA) 
    • After giving off the posterior spinal artery (PSA), posterior inferior cerebellar arteries (PICA) and anterior spinal artery (ASA), the vertebral arteries fuse to form the basilar artery 
  • The basilar artery runs along the centre of the anterior/ventral pons. It's branches are:
    • AICA
    • Multiple pontine arteries
    • Superior cerebellar arteries 
  • Posterior communicating artery connecting PCA to the internal carotid and circle of Willis ==> supplies the hypothalamus and ventral thalamus 
  • Posterior communicating artery ==> second most common location of aneurysm in circle of Willis ==> results in third nerve palsy due to compression of CN III
  • Occlusion of the BASILAR ARTERY results in ''Locked-In Syndrome''. 

 

8

Where is CSF produced? 

  • Choroid plexus is responsible for the production of CSF
  • The third ventricle communicates with the fourth ventricle via the cerebral aqueduct which when obstructed causes a non-communicating hydrocephalus. 
    • A lesion to the optic tract will cause a contralateral homonymous hemianopsia. 

9

What are the branches of the basilar artery as it runs along the pons?

The basilar artery runs along the center of the anterior/ventral pons. Its branches are:

Anterior inferior cerebellar arteries (AICA)
Multiple pontine arteries
Superior cerebellar artery

10

What is the pathway of the jaw-jerk reflex?

It is a reflex of the trigeminal system: 

Tapping the chin of a patient activates the jaw-jerk reflex:

Pathway: V3 ==> mesencephalic nucleus of V ==. motor nucleus of V ==> masseter 

11

Name a pathology associated with the following structure:

Putamen

Posterior limb of the internal capsule 

 

The putamen is the most common site of a hypertensive bleed in the central nervous system


Atrophy of the caudate nucleus is seen in Huntington’s disease 


A lesion to the posterior limb of the internal capsule results in contralateral loss of all conscious somatosensation and contralateral hemiparesis of the body and face 

12

What is the structure of the lateral ventricles? How do they communicate with the third ventricle?

  • Within the ventricles CSF is produced and secreted by the ependymal cells of the vascular choroid plexus 
    • Each lateral ventricle has a central body as well as an anterior horn, posterior horn and inferior horn. They communicate with the third ventricle via the interventricular foramen of Monro 
      • The third ventricle is between the two halves of the diencephelon (thalamus and hypothalamus)
        • It communicates with the fourth ventricle via the cerebral aqueduct 
        • Clincal correlate ==> congenital stenosis of the cerebral aqueduct can result in non-communicating hydrocephalus 
      • The fourth ventricle is within the brainstem - it is bordered ventrally by the pons and medulla and dorsally by the cerebellum. It communicates with the cisterna magna via two lateral foramina (of Luschka) and a medial foramen (of Magendie) 

13

What structures are supplied by the posterior communicating artery?

The posterior communicating artery connects the PCA to the internal carotid and circle of Willis. It supplies the hypothalamus and ventral thalamus.

14

Outline the auditory pathway. 

The cochlear nerve CN VIII transmits auditory signals from the inner ear 

First order neurons - the spiral ganglion contains bipolar cells that innervate hair cells within the organ of corti - their axons make up CN VIII

CN VIII enters the brainstem at the CP angle, the synapses in cochlear nuclei 

Second order neurons - decussating fibers from the ventral cochlear nuclei travel in the trapezoid body (within the pons) and synapse in the now contralateral superior olivary nucleus (note that most fibers decussate but some remain ipsilateral) 

Third order neurons: Neuron cell bodies within the superior olivary nucleus send axons rostrally through the lateral lemniscus and synapse in the inferior colliculus 

Fourth and fifth order neurons - neurons in the inferior colliculus project to the medial geniculate body of the thalamus. Neurons from the thalamus project to the auditory cortext within the transverse gyrus of the temporal lobe. 

 

15

What structures are supplied by the middle cerebral artery?

The middle cerebral artery (MCA) supplies the lateral portion of the cerebral hemisphere, including Broca’s area, Wernicke’s area, and motor-sensory cortices of the contralateral trunk-arm-face.

16

What are the divisions of the CN V nerve? 

Distal to the trigeminal ganglion, CN V branches into three main divisions: the ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves.

 

V2 innervates mucosa of the upper mouth, nose, pharynx, palate and upper teeth, and cranial dura.


V3 carries sensation from the external auditory meatus and external surface of the tympanic membrane, mucosa of the cheeks and floor of the mouth, the tongue, and the cranial dura.

17

What are the penetrating branches off the middle cerebral artery called and what structures do they supply?

Lenticulostriate arteries are penetrating branches of the MCA that supply the internal capsule and structures of the basal ganglia.

18

What artery supplies the following structures: CN VI nucleus and nerve, corticospinal fibers, medial lemniscus, medial longitudinal fasciculus?

AICA

Other structures within the pons supplied only by pontine arteries:

Abducens (CN VI) nucleus and nerve
Corticospinal fibers
Medial lemniscus
Medial longitudinal fasciculus

19

What is the location of the spinal nucleus of V?

The spinal nucleus of V (along with the spinal tract of V) is a long collection of nerve bodies and fibers. It begins at the junction of the pons and medulla, caudal to the main sensory nucleus, and stretches to the level of C2 or C3 within the spinal cord.

20

What is the structure of the choroid plexus?

The choroid plexus is composed of blood vessels within pia matter that are covered byependymal cells.

21

What are the symptoms of medial medullary syndrome? 

  • The anterior spinal artery (ASA) supplies the spinal cord (except dorsal columns) including the lateral corticospinal tract, medial lemniscus and hypoglossal nerve (CN XII)
  • Infartion in the paramedian branches of the ASA may result in medial medullary syndrome 
    • Contralateral hemiparesis in the lower extremities (lateral corticospinal tract) 
    • Decreased contralateral propioception (dorsal column medial lemniscus tract) 
    • Ipsilateral paralysis of hypoglossal nerve 
  • Occlusion, infarction, or acute compression (inferior to the medulla oblongata) may result in anterior spinal artery syndrome:

    • Bilateral paralysis below the level of injury (lateral corticospinal tract)

    • Loss of pain and temperature below the level of injury (spinothalamic tract)

    • Preserved proprioception (dorsal column medial lemniscus tract)

22

What are the symptoms of an anterior spinal artery syndrome?

Occlusion, infarction, or acute compression (inferior to the medulla oblongata) may result in anterior spinal artery syndrome:

Bilateral paralysis below the level of injury (lateral corticospinal tract)
Loss of pain and temperature below the level of injury (spinothalamic tract)
Preserved proprioception (dorsal column medial lemniscus tract)

23

What structures are supplied by the posterior cerebral artery?

The posterior cerebral artery (PCA) supplies the midbrain, lateral and medial geniculate bodies, and occipital lobe (including the visual cortex).

The superior colliculus, in the midbrain, is not supplied by the PCA. It is supplied by the superior cerebellar artery.


Occlusion of the PCA may result in contralateral hemianopia with macular sparing.(Macular sparing occurs because there is a small amount of collateral supply to the occipital cortex representing the macula from the MCA)

24

What is the:

cingulate gyrus

Corpus callosum 

Parieto-occipital sulcus 

Primary visual cortex

The cingulate gyrus is part of the limbic system and has a role in depression and schizophrenia.


The corpus callosum facilitates interhemispheric communication.


The parieto-occipital sulcus separates the precuneus (anterior) from the cuneus (posterior) 


The primary visual cortex is located on the superior and inferior gyri surrounding the calcarine fissure

25

What are three possible sequelae of anterior cerebral artery occlusion?

  • The anterior cerebral artery supplies the anteromedial surface of the cerebral hemisphere, the olfactory bulb and tract, motor sensory cortices for the contralateral foot and leg 
  • The ACA has two continuous segments:
    • designated A1 and A2
      • A1 is proximal to the anterior communicating artery 
      • A2 is distal to the anterior communicating artery 
  • The anterior communicating artery is the most common location for berry aneurysm in the circle of Willis - resulting in bitemporal hemianopsia 
  • The medial striate arteries are the largest branches of the ACA:
    • Supplying the:
      • head of the caudate
      • anterior portion of the lentiform nucleus 
      • anterior limb of the internal capsule 
  • Occlusion of the ACA may result in:
    • Paralysis/sensory loss of contralateral foot and leg 
    • Gait apraxia (loss of ability to have normal functioning of the lower limbs like walking) 
    • Urinary incontinence 

26

Are cisterns part of the ventricular system?

  • Cisterns are large cavernous regions of the subarachnoid space, they are not part of the ventricular system 
  • The cisterna magna is a large cavity dorsal to the brainstem and inferior to the cerebellum - continuous with subarachnoid space of the spine 
    • IT also lies between the medulla and cerebellum, receives CSF from fourth ventricle via median foramen of Magendie = largest of the cisterns 
  • Pontine cistern - ventral to the pons 
  • Interpeduncular cistern - lies between cerebral peduncles - contains bifurcation of the basilar artery 
  • Quadrigeminal cister - dorsal to the midbrain - has great vein of Galen.