THALAMUS
THALAMUS ( चेतक )
situation ( स्थान )
lies above midbrain ( मध्यमस्तिष्क के ऊपर )
one on each side of a slit like cavity called third ventricle
shape and size( अकार )
ovoid mass of grey matter
3.5 cm in length , 1.5 cm in breadth
External features
two ends ( दो छोर )
anterior end ( अग्र )
narrow
constitutes tubercle of thalamus
forms posterior boundary of interventricular foramen
posterior end ( पश्च )
expanded called pulvinar
overhangs
medial and lateral geniculate bodies
superior colliculi with their brachia
four surfaces
superior surface
lateral part
forms floor of central part of lateral ventricle ( पार्श्व विलय )
medial part
covered by tela choroidea of 3rd ventricle
inferior surface
anterior part
fused with sub-thalamus
posterior part
free
inferior aspect of pulvinar
medial surface
greater part of lateral wall of third ventricle
lateral surface
medial boundary of posterior limb of internal capsule
INTERNAL STRUCTURE
MAINLY GREY MATTER
divided by y shaped internal medullary lamina
anterior
tubercle
lies between limbs of Y
medial
on medial side of stem of Y
large Medial dorsal
small medial ventral
lateral
on lateral side of stem of Y
dorsal
lateral dorsal
lateral posterior
large caudal nuclear mass
pulvinar
ventral
ventral-lateral (ventral intermediate )
ventral- anterior
ventral - posterior
ventral posterolateral
ventral posteromedial
other nuclei
intralaminar nuclei
midline ( paraventricular nuclei)
reticular nucleus
WHITE MATTER
lateral surface of thalamus
thin layer
external medullary lamina
superior surface
stratum zonale
inside thalamus
internal medullary lamina
anterior
medial
lateral
lateral dorsal
lateral posterior
pulvinar
ventral anterior
ventral lateral
ventral posterolateral
ventral posteromedial
intralaminar
midline
reticular nuclei
centromedian nucleus
medial geniculate
body
lateral geniculate
body