THALAMUS ANATOMY.pptx
- 1. DIENCEPHALON Dr B Vinod Mch Neurosurgery Resident Gandhi medical college Hyderabad
- 2. Situated cranial to the midbrain and is more or less completely surrounded by the cerebrum Cavity within the diencephalon is termed the 3rd ventricle. It communicates on either side with the lateral ventricle of the cerebral hemisphere. The cavity of the 3rd ventricle divides the diencephalon into two (right and left) symmetrical halves.
- 3. The diencephalon is divided into two major parts: pars dorsalis and pars centralis. These subdivisions are seen in midsagittal view of the brain and are separated from each other by a shallow groove, the hypothalamic sulcus, which extends from interventricular foramen to the rostral end of the cerebral aqueduct of the midbrain
- 7. Long axes of the thalami are set obliquely, running backward and laterally. The pointed anterior ends are nearer to the median plane, whereas the wider posterior ends are separated from each other by pineal body, superior colliculi, and habenular triangles. The thalami are usually attached across the median plane by a narrow neothalamic adhesion. Each thalamus forms most of the lateral wall of the 3rd ventricle and floor of the central part of the lateral ventricle.
- 8. Functionally, thalamus is considered as the great sensory gate way to the cerebral cortex. It receives impulses from the opposite half of the body and transmits most of them to the sensory area of the cerebral cortex (Brodmann areas 3, 2 , 1).
- 9. EXTERNAL FEATURES Has 2 ends and 4 surfaces. Anterior end:-Narrow and forms posterior boundary of interventricular foramen. Posterior end:- expanded known as pulvinar, overhangs medial , lateral geniculate bodies and superior colliculi
- 10. Superior surface: Its lateral part forms the floor of the central part of the lateral ventricle and its medial part is covered by the tela choroidea of the 3rd ventricle. Inferior surface Its anterior part is fused with the subthalamus while its posterior part is free, forming the inferior aspect of the pulvinar. Medial surface It forms the greater part of the lateral wall of the 3rd ventricle. Lateral surface It forms the medial boundary of the posterior limb of the internal capsule.
- 14. ARTERIAL SUPPLY
- 23. VENTRAL POSTERIOR NUCLEUS The ventral posteromedial nucleus (VPM) receives general sensory modalities from the head and face through trigeminal lemniscus and tastes sensations from taste buds through solitario-thalamic tract. Larger lateral portion, the ventral posterolateral nucleus (VPL) receives exteroceptive sensations (pain, touch, temperature) through spinal lemniscus and proprioceptive sensations(muscle and joint sense,vibration, two-point discrimination) through medial lemniscus, from the rest of the body except face and head
- 38. Thank you