Diencephalon: Thalamus

Question 1

Site

Answer 1

Above midbrain and projects beyond it both in front and behind

Question 2

Shape and relations

Answer 2

Oval
Has 2 ends and 4 surfaces:
1. Anterior end
2. Posterior end
3. Upper surface
4. Lower surface
5. Lateral surface
6. Medial surface

Question 3

Anterior end

Answer 3

1. Narrow, rounded
2. Forms interventricular foramen posterior boundary

Question 4

Posterior end

Answer 4

1. Expanded to form prominent swelling
2. Pulvinar which overhangs medial and lateral geniculate bodies

Question 5

Upper surface: Extraventricular medial part

Answer 5

Covered by:
1. 3rd ventricle tela choroidea
2. Fornix body

Question 6

Upper surface: intraventricular lateral part

Answer 6

In floor of lateral ventricle body with caudate body separated from it by
1. Stria terminalis
2. Thalamo-striate vein

Question 7

Lower surface: anterior part

Answer 7

Lies on hypothalamus

Question 8

Lower surface: middle part

Answer 8

Lies over Subthalamus which connects it with midbrain cerebral peduncles

Question 9

Lower surface: posterior part

Answer 9

Overhangs medial and lateral geniculate bodies

Question 10

Lateral surface

Answer 10

Related to internal capsule posterior limb separating it from lentiform nucleus

Question 11

Medial surface

Answer 11

1. Forms 3rd ventricle lateral wall and connected to its fellow by gray matter mass/ inter thalamic connection
2. Separated from hypothalamus and Subthalamus by hypothalamic sulcus

Question 12

Blood supply

Answer 12

1. Posterior cerebral artery (basilar artery terminal branch)
2. Posterior communicating artery (ICA branch)

Question 13

Posterior cerebral artery supply

Answer 13

Main supply through posterior choroidal branch, medial and lateral central branches

Question 14

Nuclei

Answer 14

Divided anatomically into subgroups of nuclei by white matter Y shaped sheet, internal medullary lamina

Question 15

Types of nuclei

Answer 15

1. Anterior nucleus
2. Medial nucleus
3. Lateral nucleus
4. 2 posterior nucleus
5. 3 scattered nuclei

Question 16

Anterior nucleus site

Answer 16

Lies between both limbs of lamina

Question 17

Medial nucleus site

Answer 17

Lies medial to lamina

Question 18

2 posterior nuclei constitutes

Answer 18

Thalamus posterior expanded end which overhangs medial and lateral geniculate bodies

Question 19

3 scattered nuclei

Answer 19

1. Intralaminar nucleus
2. Midline nucleus
3. Reticular nucleus

Question 20

Lateral nucleus site

Answer 20

Lies lateral to lamina

Question 21

Lateral nucleus subdivisions

Answer 21

1. Dorsal part
2. Ventral part
   Subdivided into several smaller nuclei

Question 22

Most important ventral nuclei

Answer 22

PVNT (posterior ventral nucleus of thalamus)

Question 23

PVNT is divided into

Answer 23

1. Lateral PLVNT
2. Medial PMVNT

Question 24

PLVNT receives

Answer 24

1. Conscious proprioceptive fine touch: from body below head via medial lemniscus
2. Pain, temperature, crude touch, pressure: from body below head via spinal lemniscus

Question 25

PMVNT receiving

Answer 25

Pain, touch, temperature, proprioceptive, taste sensations from head via Trigeminal lemniscus

Question 26

PVNT efferent

Answer 26

To main sensory area (3,1,2) in parietal lobe posterior central gyrus