Brainstem Flashcards
Where is tegmentum of the midbrian located?
Between the cerebral aqueduct and the pars compacta of the substantia nigra, is the tegmentum.
What is cerebral peduncle of midbrain?
Collectively, the tegmentum and the basis pedunculi are referred to as the pedunculus cerebri, otherwise called the cerebral peduncles.
The midbrain is derived from (mesencephalon/metencephalon) _________.
Mesencephalon
From where does the midbrain start and end?
It extends from the superior medullary velum of the pons (roof of the fourth ventricle) to the posterior commissure of the third ventricle.
The cerebral peduncles are caudal continuations of the ___________?
Internal Capsule
What is internal capsule?
A white matter structure that separates the thalamus and caudate nucleus from the lentiform nucleus [globus pallidus internus and externus, and the putamen combined]
The space between the peduncles where the posterior perforated substance resides is known as the ____________?
Interpeduncular fossa
What is the relation of optic tract with anterior surface of midbrain?
The optic tracts are related to the cerebral peduncles anteriorly proximal to the optic chiasm and laterally as the tracts travel distal to the chiasm.
What are the structures present laterally to the midbrain?
The uncus of the temporal lobe, lateral geniculate body (LGB) and medial geniculate body (MGB) are all in lateral relations to the cerebral peduncles; with the former being most anterior and the latter being most posterior of the structures.
What cranial nerve emerges from the medial side of the cerebral peduncle?
Oculomotor nerve (CN III). If exactly where then the superior pontine sulcus (border between the midbrain and pons)
What is corpora quadrigeminini?
It is comprised of paired superior colliculi and inferior colliculi located posteriorly on the midbrain.
The left and right colliculi are separated by ___________?
Continuation of the frenulum of the superior medullary velum
What is the site of emergence of the trochlear nerve (CN IV)?
Frenulum of the superior medullary velum
What is the course of the trochlear nerve?
It exits the brainstem posteriorly and courses around the lateral part of the cerebral peduncle to gain access to the cavernous sinus of the middle cranial fossa.
What type of information does the lateral geniculate body receive?
The LGB receives visual input from the optic tract and subsequently relays this information to the superior colliculi via the superior brachium (running inferior to the pulvinar of the thalamus)
