- Thalamus: paired ovoid mass of grey matter, one on each side of the third ventricle, forming most of its lateral wall; the principal sensory relay and integration station to the cerebral cortex.
- Size3.5 cm long, 1.5 cm broad
- Lies above the midbrain (separated from it by the subthalamus), and is joined to its fellow by the interthalamic connexus (adhesion).
External Features
- Each thalamus has two ends and four surfaces.
External features of the thalamus
Feature
Anterior end
- Description
- Narrow; tubercle of thalamus; forms posterior boundary of the interventricular foramen
Posterior end
- Description
- Expanded pulvinar; overhangs medial and lateral geniculate bodies and superior colliculi
Superior surface
- Description
- Floor of central part of lateral ventricle (lateral part); covered by tela choroidea of third ventricle (medial part)
Inferior surface
- Description
- Anterior part fused with subthalamus; posterior part free, forms inferior aspect of pulvinar
Medial surface
- Description
- Forms greater part of lateral wall of third ventricle
Lateral surface
- Description
- Forms medial boundary of posterior limb of internal capsule