Fourth Ventricle Flashcards

1
Q

Definition and site

A

Cavity of hindbrain lying between pons and upper part medulla (in front) and cerebellum (behind)

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2
Q

Shape and angles

A

Diamond shaped
4 angles
1. Upper angle
2. Lower angle
3. Lateral angle

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3
Q

Upper angle

A

Continuous with sylvius aqueduct

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4
Q

Lower angle

A

Continuous with central canal closed medulla

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5
Q

Lateral angle

A

2 lateral angles
Each at meeting of SCP and ICP of its own side

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6
Q

Boundaries

A
  1. Roof
  2. Floor
  3. 2 lateral borders
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7
Q

Lateral borders

A
  1. Above
  2. In middle
  3. Below
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8
Q

Lateral borders: above

A

SCP

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9
Q

Lateral borders: in middle

A

Lateral angle forming lateral recess

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10
Q

Lateral borders: below

A
  1. Gracile tubercle
  2. Cuneate tubercle
  3. ICP
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11
Q

Floor

A

Divided by median longitudinal sulcus into 2 similar halves
It is also divided by transverse nerve bundles (medullary stria) into:
1. Upper pontine part
2. Lower medullary part

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12
Q

Upper pontine part

A

Dorsal (tegmental) surface pons

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13
Q

Dorsal surface pons

A

Forms upper 1/2 of 4th ventricle floor separated from back of open medulla by medullary stria and bounded lateral by SCP

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14
Q

Dorsal surface pons features

A
  1. Medial eminence and facial colliculus
  2. Sulcus limitans
  3. Upper vestibular area
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15
Q

Medial eminence and facial colliculus

A

(At medial eminence lower end produced by abducent nucleus and encircling facial nerve fibers

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16
Q

Sulcus limitans

A

Lateral to medial eminence and its lower part lies lateral to facial colliculus and called superior fovea

17
Q

Upper vestibular area

A

Overlies superior and lateral vestibular nuclei

18
Q

Dorsal surface of medulla upper 1/2 (open medulla)

A

Forms lower 1/2 of 4th ventricle floor separated from pons back by medullary stria and bounded lateral by ICP

19
Q

Open medulla transversed by

A
  1. Vertical median sulcus
  2. Lateral to it inverted v shaped depression (inferior fovea)
  3. On each side, inferior fovea divides medullary part in 3 triangular areas
20
Q

Medullary part of open medulla is divided into 3 parts from medial to lateral

A
  1. Hypoglossal trigone
  2. Vagal trigone
  3. Lower vestibular area
21
Q

Hypoglossal trigone

A

Overlies hypoglossal nerve nucleus

22
Q

Vagal trigone

A

Overlies vagus nerve dorsal nucleus

23
Q

Lower vestibular area

A

Overlies inferior and medial vestibular nuclei

24
Q

Area postrema

A
  1. Vomiting center
  2. Protruberence at 4th ventricle inferoposterior limit
25
Q

Superior roof

A

Superior medullary velum (thin sheet of white matter connecting 2 SCP)

26
Q

Inferior roof: upper area

A

Cerebellum nodule and inferior medullary velum (connecting 2 ICP)

27
Q

Inferior roof: lower area

A

Tela choroidea of 4th ventricle (where choroid plexus invaginates 4th ventricle and where pia mater comes in contact with ependyma).

28
Q

Recesses

A
  1. Median recess
  2. 2 lateral recesses
29
Q

Median recess

A

4th ventricle roof is drawn backwards towards cerebellum forming median recess with upper wall formed by superior medullary velum and lower wall formed by cerebellum

30
Q

2 lateral recesses

A
  1. At 4th ventricle lateral angles 2. Each runs forward around medulla to open anterior into subarachnoid space by lateral aperture (foramen luschka)
31
Q

Communication

A
  1. Upper angle
  2. Lower angle
  3. With subarachnoid space
32
Q

Communication: upper angle

A

Communicates with 3rd ventricle through sylvius aqueduct

33
Q

Communication: lower angle

A

Communicates with central canal of medulla

34
Q

Communication: subarachnoid space

A

By median (foramen of magendie which opens in cisterna magna) and 2 lateral apertures (foramina of luschka which open into ponto-medullary cistern)

35
Q

Choroid plexus

A
  1. Invaginates lowermost area of 4th ventricle roof above median aperture of magendie
  2. T shaped with median stem and 2 arms extending to lateral recesses
  3. Blood supply is posterior inferior cerebellar arteries