The Brainstem Flashcards
What is the brainstem?
Part of the brain that lies superior to the spinal cord
3 parts
Midbrain
Pons
Medulla
What cranial fossa does the brainstem lie in?
Foramen magnum
Embryologically which 2 vesicles of the neural tube give rise to the brainstem?
Mesencephalon
Rhombencephalon
What are the cavities of the brainstem?
Cerebral aqudeuct
4th ventricle
What is the groove that seperates the pons from medulla?
Pontomedullary junction
Which cranial nerves emerge from the pontomedullar junction?
Glossopharyngeal- Emerges from the lateral side mid pons
Vagus- Lateral side
Hypoglossal- Pyramids laterally
Accessory- Lateral side (most inferior)
What do the olives do?
Inferior Olivary nucleus which is implicated in motor coordination
What do the pyramids do?
Motor fibres – Corticobulbular & Corticospinal tratcs
What are the decussation of the pyramids?
Allow fibres to cross over
Posteriorly on the medulla, identify the parts of the medulla known as the “open” and “closed” part. Which of these is superior and which inferior?
Open = Superior part, Closed = Inferior part.
WHat structure does the open part of the medulla open into?
The fourth ventricle
What does the medulla pass through to become the spinal cord?
Foramen magnum
Which part of this section would motor fibres (of the pyramidal tract) and sensory fibres that form the medial lemniscus occupy?
Motor Fibres – In small separate tracts dispersed within the Pontine Nuclei at anterior.
Sensory fibres – Sits in the middle – between Pontine nuclei & nuclei of Reticular formation
What lies superior and ifnerior to the midbrain?
Superior- Diencephalon
Inferior- Pons
The cerebral peduncles - what kind of fibres make up the cerebral peduncles and where are they destined for?
Motor fibres destined for the cerebral hemispheres
What is the diencephalon made up on?
Thalamus, Hypothalamus (& Pituitary) and the Epithalamus (Pineal Gland).
What does the diencephalon lie between?
Cerebral Hemispheres and Midbrain
Most of these structures are deep and cannot be seen from the surface except for a small part of the hypothalamus.
What are the surface projections visible on the surface of the hypothalamus called?
Mamillary body
