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Questions and Answers
Which structure forms the roof of the fourth ventricle's upper part?
Which structure forms the roof of the fourth ventricle's upper part?
What is the function of the Foramen of Magendie?
What is the function of the Foramen of Magendie?
Which of the following structures is NOT part of the floor of the fourth ventricle?
Which of the following structures is NOT part of the floor of the fourth ventricle?
What are the two lateral apertures in the fourth ventricle called?
What are the two lateral apertures in the fourth ventricle called?
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Which feature divides the floor of the fourth ventricle into two symmetrical halves?
Which feature divides the floor of the fourth ventricle into two symmetrical halves?
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Which structure is NOT part of the lateral boundaries of the fourth ventricle?
Which structure is NOT part of the lateral boundaries of the fourth ventricle?
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How does the fourth ventricle connect to the cranial cavity?
How does the fourth ventricle connect to the cranial cavity?
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What type of shape does the floor of the fourth ventricle resemble?
What type of shape does the floor of the fourth ventricle resemble?
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Which of the following is a function of the lateral recesses of the fourth ventricle?
Which of the following is a function of the lateral recesses of the fourth ventricle?
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Which structure does cerebrospinal fluid (CSF) pass through to get from the third ventricle to the fourth ventricle?
Which structure does cerebrospinal fluid (CSF) pass through to get from the third ventricle to the fourth ventricle?
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What is the primary function of the apertures of the fourth ventricle?
What is the primary function of the apertures of the fourth ventricle?
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What primarily causes hydrocephalus?
What primarily causes hydrocephalus?
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Which apertures of the fourth ventricle primarily allow CSF to enter the subarachnoid space?
Which apertures of the fourth ventricle primarily allow CSF to enter the subarachnoid space?
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Which structure helps to regulate the absorption of cerebrospinal fluid back into the venous system?
Which structure helps to regulate the absorption of cerebrospinal fluid back into the venous system?
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What condition is characterized by swelling of the ventricles due to increased fluid pressure?
What condition is characterized by swelling of the ventricles due to increased fluid pressure?
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The CSF primarily produced in which part of the ventricular system?
The CSF primarily produced in which part of the ventricular system?
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What is the role of the median aperture in relation to the fourth ventricle?
What is the role of the median aperture in relation to the fourth ventricle?
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Which structure forms the roof of the fourth ventricle?
Which structure forms the roof of the fourth ventricle?
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The choroid plexus is primarily composed of which type of tissue?
The choroid plexus is primarily composed of which type of tissue?
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Study Notes
Fourth Ventricle
- Tent-shaped space between cerebellum, pons, and upper medulla (anteriorly)
- Upper part has superior cerebellar peduncles and superior medullary velum
- Lower part has pia and ependyma (inferior medullary velum) and foramen of Magendie
- Foramen of Magendie provides communication with the cisterna magna
- Lateral apertures (foramen of Luschka) connect lateral recesses of 4th ventricle to the subarachnoid space at the cerebellopontine angle
Lateral Boundaries of Fourth Ventricle
- Upper part: Superior cerebellar peduncles
- Lower part: Gracile tubercle, cuneate tubercle, inferior cerebellar peduncle
Floor of Fourth Ventricle
- Rhomboid/diamond-shaped
- Has four angles:
- Inferior angle: Continuous with central canal of spinal cord
- Superior angle: Continuous with cerebral aqueduct
- Lateral angles: Meeting of superior and inferior cerebellar peduncles (SCP and ICP)
Features of the Floor of the 4th Ventricle
- Median sulcus: extends from superior to inferior angles, dividing the floor into two symmetrical halves
- Stria medullaris bundles: lie between pontine and medullary parts
- Medial eminences: two elevations on each side of median sulcus
- Facial colliculi: two swellings on each side of median sulcus, each for abducent nucleus and loop of facial nerve
Superior Fovea
- Small depression between medial eminence and vestibular area
Inferior Fovea
- Small depression in lower part of floor
Hypoglossal Triangle
- Between inferior fovea and median sulcus
Vagal Triangle
- Between limbs of fovea
Vestibular Area
- Lateral to foveas
Third Ventricle
- Slit-like cavity between two thalami
- Communicates with fourth ventricle through cerebral aqueduct
- Communicates with lateral ventricles through interventricular foramen (foramen of Monro)
Third Ventricle Walls
- Roof: Pia-ependyma spans between two striae medullaris thalami, situated along the dorsomedial border of the thalamus
- Floor: Optic chiasma, tuber cinereum and infundibulum, posterior perforated substance, tegmentum of midbrain (posteriorly)
- Anterior wall: Anterior commissure, anterior column of fornix, lamina terminalis
- Posterior wall: Pineal body, posterior commissure, cerebral aqueduct
- Lateral wall: Thalamus, hypothalamic sulcus, hypothalamus
Lateral Ventricle
- Located within cerebral hemisphere
- One on each side of median plane
- Communicates with the third ventricle through interventricular foramen
- Approximately C-shaped
- Consists of anterior (frontal) horn, body (central part), posterior (occipital) horn, and inferior (temporal) horn
Posterior Horn of Lateral Ventricle
- Extends from splenium to occipital pole
- Roof and lateral wall: Tapetum of corpus callosum
- Floor and medial wall: two long elevations
- Bulb of posterior horn (formed by forceps major of corpus callosum)
- Calcar avis (produced by calcarine sulcus)
Inferior Horn of Lateral Ventricle
- Lies within temporal lobe
- Roof: Stria terminalis, tail of caudate nucleus, amygdala
- Lateral wall: Tapetum of corpus callosum
- Floor: Collateral eminence produced by collateral sulcus, hippocampus, and fimbria (axons of hippocampus, continuous with crus of fornix)
Cerebrospinal Fluid (CSF)
- Clear colourless fluid containing little protein and few cells
- Produced partly by an active secretory process and partly by passive diffusion
- Present in ventricular system, cranial subarachnoid space, and spinal subarachnoid space
Volume of CSF
- Approximately 150 ml in combined ventricular and subarachnoid spaces
- Produced continuously
Formation of CSF
- By choroid plexus of ventricles (lateral, third, and fourth ventricles)
Mechanism of Reabsorption of CSF
- Reabsorbed into venous system, mainly superior sagittal sinus
- Reabsorption occurs through arachnoid villi and granulations
Subarachnoid Cisterns
- Varying depth in different regions; spanned by arachnoid mater
- Cerebellomedullary cistern, or cisterna magna located between cerebellum and dorsal surface of medulla, continuous inferiorly with posterior part of spinal subarachnoid space
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Description
Explore the intricate structure of the fourth ventricle, situated between the cerebellum, pons, and medulla. This quiz delves into its boundaries, floor features, and connections, expanding your understanding of this critical brain region. Perfect for students studying neuroanatomy.
