Fourth Ventricle Flashcards
Definition and site
Cavity of hindbrain lying between pons and upper part medulla (in front) and cerebellum (behind)
Shape and angles
Diamond shaped
4 angles
1. Upper angle
2. Lower angle
3. Lateral angle
Upper angle
Continuous with sylvius aqueduct
Lower angle
Continuous with central canal closed medulla
Lateral angle
2 lateral angles
Each at meeting of SCP and ICP of its own side
Boundaries
- Roof
- Floor
- 2 lateral borders
Lateral borders
- Above
- In middle
- Below
Lateral borders: above
SCP
Lateral borders: in middle
Lateral angle forming lateral recess
Lateral borders: below
- Gracile tubercle
- Cuneate tubercle
- ICP
Floor
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
Upper pontine part
Dorsal (tegmental) surface pons
Dorsal surface pons
Forms upper 1/2 of 4th ventricle floor separated from back of open medulla by medullary stria and bounded lateral by SCP
Dorsal surface pons features
- Medial eminence and facial colliculus
- Sulcus limitans
- Upper vestibular area
Medial eminence and facial colliculus
(At medial eminence lower end produced by abducent nucleus and encircling facial nerve fibers