Q.3
True about corpus callosum -
a) Unite far area of two sides of brain
b) Connect two frontal lobe
c) Unite two hemisphere
d) Superiorly related to - Indusium griseum
e) Unite adjacent & widespread separated gyri in the same lobe
A. ABCD
B. BCD
C. DCE
D. BC
Explanation :
Corpus callosum connects homotopic (symmetrical) and hetrotopic (anatomically different but functionally similar) areas of two hemispheres.
Fibers of genu (forceps minor) connect medial and lateral surfaces of frontal lobes.
Upper convex surface is clothed intimately by indusium griseum, a thin sheet of grey matter.
Lower concave surface is related to septum pellucidum, ependyma of lateral ventricle, tela choroidea, and transverse fissure (containing great cerebral vein).
Q.13
True regarding cavity of diencephalons is -
a) Septum pellucidum forms partition
b) Septum pellucidum cavity opens superiorly
c) Lateral wall is lamina terminalis
d) Inter thalamic adhesions join lateral walls
e) Lamina terminalis contain anterior communicating artery
A. DE
B. ABC
C. ACD
D. ABE
Explanation :
Cavity of diencephalon is third ventricle.
Septum pellucidum forms partition of two lateral ventricles (not 3rd ventricle)
Lamina terminalis forms anterior wall (not lateral wall).
Interthalamic adhesions connects medial surface of two thalami and therefore join lateral wall of 3rd ventricle as thalami form lateral wall of 3rd ventricle.
Lamina terminalis is a thin sheet of gay matter, which extend between two hemisphere from rostrum of corpus callosum to top of optic chiasma forming the anterior wall of 3rd ventricle. It represents the rostral (cranial) boundary of embryonic neural tube. Anterior commisure crosses midline in lamina terminalis Lamina terminalis forms roof of cistern of lamina terminalis (a small, virtual cavity lying immediately below 3rd ventricle) which contains anterior communicating artery. So aneurysm formation at this site may cause intraventricular harmorrhage through thin membrane of lamina terminalis.
Q.19
True about spinal cord -
A. In adults spinal cord ends at lower border of L1 vertebra
B. Cauda equina extends from lumbar vertebra to coccyx
C. In embryonic period cord extends up to coccyx
D. All are true
Explanation :
In adults, spinal cord ends at the lower border of L1 and in newborn, it ends at L3 vertebra.
The spinal cord extends throughout the length of the vertebral canal early in fetal life.
Cauda equina is formed by roots of the lower four pairs of lumbar, five pairs of sacral and one pair of coccygeal nerves.
The spinal cord does not have the same diameter throughout, it has two enlargements (thickenings):- Cervical (C3-T2) and lumbar (L1-S3).
