Midbrain Anatomy Flashcards
Identify the three broad regions of the midbrain.
Tectum and associated colliculi (posterior)
Tegment um (middle region)
Cerebral peduncles (most antieror)
What comprises the tectum of the midbrain?
The tectum includes the right and left superior and inferior colliculi
What is the anatomical space indicated by the black arrow?
Inter peduncular fossa
What arises from the inter peduncular fossa?
CN III the Occulomotor nerve arises anteriorly from the brainstem within the inter peduncular fossa.
What arises from the inter peduncular fossa?
CN III the Occulomotor nerve arises anteriorly from the brainstem within the inter peduncular fossa.
Label the anatomical structures of the midbrain in this cross sectional image.
What is the role of the red nuclei and describe its anatomical position within the mid brain.
The red nuclei are associated with proximal limb muscle control.
The two red nuclei are located within the anterior region of the tegmentum at the level of the superior colliculi (of the tectum).
What is the role of the substantia nigra and describe its anatomical position within the midbrain.
The substantia nigra is a basal nuclear structure located within the midbrain. It functions to control voluntary movements. The substantia nigra is observed as a darkly pigmented area located anteriorly / ventrally in the tegmentum.
What is the role of the pyramidal pathways and describe its anatomical location within the midbrain.
The pyramidal pathways are the main voluntary motor pathways.
The pyramidal pathways are located medially within each (right and left regions) of the cerebral peduncle (most anterior region of the midbrain).
What special sensory nuclei are located at:
1. The superior colliculi level within the aqueduct grey zone?
2. The inferior colliculi level within the aqueduct grey zone?
The oculormotor nucleus is located within the aqueduct grey zone of the midbrain tegmentum at the superior colliculi level.
2. The trochlear nucleus is located within the aqueduct grey zone of the midbrain tegmentum, at the inferior colliculi level.
List the midbrain structures shown on this sagittal MRI (1-3)
- The tectum including colliculi (grey outline).
- The aqueduct (blue).
- The tegmentum (pink outline).
What structures of the midbrain can you identify in this MRI cross section?
Aim for the basic regions with this card.
Grey outline - tectum.
Blue outline - aqueduct.
Pink outline - tectum.
Green # - inter peduncular fossa.
Anterior to the pink outline is the cerebral peduncles.
What are these advanced structures of the midbrain indicated by the various colours in the MRI cross section?
Red - red nucleus
Deep pink - ventral region of the tegmentum.
Light blue - oculomotor nucleus.
Orange - pyramidal pathways within the cerebral peduncle.
Yellow - general sensory pathways.
Green - periaqueductal grey matter.
