This document provides an overview of the anatomy of the sella and juxtasellar region. It describes the structures of the sphenoid bone including the sella turcica, which contains the pituitary gland. Adjacent areas including the cavernous sinus, diaphragm sellae, and optic chiasm are also outlined. The pituitary gland itself and its relationship to surrounding structures like the infundibulum and suprasellar cistern are defined. Other areas such as the diencephalon, basal ganglia, limbic system, hippocampus, and various commissures are also summarized.
18. PITUTARY
• In cases of visual failure / endocrine
abnormality.
• At the level of optic nerve.
• Situated in pituitary fossa – above the sphenoid sinus, with
cavernous sinus on each side.
• Superiorly suprasellar cistern is present.
• < 8 - 9mm height.
• Infundibulum is large in females
• Normal pituitary enhance with contrast on CT / MRI.
19. • Antr. Adenohypophysis – dovelops from ratke’s pouch
• Postr. neurohypophysis, infundibulum – dovelops from
downgrowth of neuroectoderm
20. Tuber cinareum is the lamina of grey matter – b/w mammillary body
and optic chiasma.
21.
22. CORONAL T 1 images with thin
(3 mm) sections
• Anterior lobe is ISOINTENSE on T1 and T2
• Posterior lobe is HYPERINTENSE on T1 and HYPO on T2.
• Infundibulum is HYPERINTENSE on FLAIR.
• Rim of hypointensity – cortical bone of dorsum sella
• Hyperintense marrow of clivus postr. to it.
29. • Diencephalon is divided into two halves by 3rd ventricle.
• Each diencephalon has dorsal and ventral parts, demarcated by
‘hypothalamic sulcus’.
dorsal – thalamus, epithalamus
ventral – hypothalamus, subthalamus
RadioGraphics 2007; 27:1087–1108
30. THALAMUS
• Ovoid mass of grey matter
• Poles – antr. : postr. boundary of IV foramen.
postr. (PULVINAR) : projects
beyond 3rd V , lies just above and
lateral to colliculi.
31. • Upper surface – dorsolaterally thalamostriate V and S.terminalis.
part of floor of 3rd ventricle.
• Inferior surface - continues with tegmentum of mid brain
• Medially – 3rd ventricle
• Laterally – lentiform N, separated by internal capsule.
Two thalami are apposed medially
by massa intermedia.
32.
33.
34. EPITHALAMUS
1. Pineal body
2. Habenular N
3. Habenular comissure
4. Posterior comissure
PINEAL BODY : balloon shaped – projects backwards below the
splenium of corpus callosum and rests over supr. colliculi.
HABENULAR NUCLEI : situated in habenular trigone.
COMISSURES - habenular and posterior .
39. HYPOTHALAMUS
• Most ventral part of diencephalon , and it
forms floor and wall of antr. 1/3rd of 3rd V.
• Extent : lamina terminalis to mammillary bodies
• Relations : dorsally – hypothalamic sulcus
ventral – floor of 3rd ventricle. It
constitutes mamillary bodies, infundibulum, optic chiasma.
medial – 3rd ventricle
lateral – internal capsule and subthalamus
Tuber cinerium extends posteriorly from infundibulum to
mamillary bodies
40.
41.
42.
43.
44. MAMMILLARY BODIES
• These are one of the nuclear masses of hypothalamus.
• Each contains – medial, lateral and intercalated nuclei.
• Receive fibres from fornix and efferents to antr. thalamus.
• Postr. to mammillary bodies, lies postr. perforated substance.
48. BASAL GANGLIA
• Corpus Striatum = Caudate N + Lentiform N (P + GP) .
• Amygdala – tail of caudate N comes in contact with amygdala ,
but without any structural or functional connections
• Claustrum – thin strip of grey matter
b/w putamen and insula
49.
50. CAUDATE NUCLEUS
‘C’ shaped with concavity facing inferiorly.
• Head – indents the frontal horn.
(shape same in axial and coronal cuts)
• Body – starts from IV foramen and is seen along side of lateral
ventricle.
• Tail – lies above temporal
horn ; continues with
amygdala.
51. • Lentiform N –
supr. – C. radiata and C. callosum.
infr. – antr. perforated substance and antr. comissure.
• Internal capsule – ‘boomrang’
shaped thick white matter.
52.
53. LIMBIC SYSTEM
1. Olfactory pathway
2. Pyriform lobe
3. Limbic lobe
4. Amygdala
5. Hippocampal complex
6. Parts of hypothalamus
and thalamus
55. HIPPOCAMPUS
• Lies on floor of temporal horn of lateral V.
• Parts : head and tail – curves medially
body – seen on parasaggital
plane.
Hungarian neuroscientist Laszlo Seress' 1980 preparation
57. INDUSIUM GRISEUM : vestigial
• thin sheet of grey matter covering outer convex surface of
corpus callosum.
• Contains medial and lateral longitudinal striae.
• Antr.ly it continue as paraterminal gyrus.
Postr.ly continues as dentate gyrus.
58. • On coronal cuts, it is seen as rolled structure containing Ammon’s
horn and dentate gyrus. Ammon’s horn continues with the PHG
and is convex laterally.
59. • Relations : above and lateral to it – temporal horn of lateral V.
(above temporal horn is tail of caudate N , and supr. to it is
amygdyla).
• PHG – is present on medial aspect of temporal lobe
antr.ly it continue as uncus
63. AMYGDALA
• Present at roof of infr. horn of lateral ventricle , close to its tip.
• Continues behind with tail of caudate N.
• Stria terminalis starts from it.
64. FORNIX
• Sole efferent fibres from fornix
• Begin from hippocampus as alveus and fimbriae.
• Parts –
- crura
- body
- columns
- comissure
65. • On reaching splenium, fimbriae divide into –
dorsal fornix – continue as inducium gracium.
ventral fornix – fornix proper.
• Upper surface of body is related to SP. At level of IV foramen, apex
divides into two columns.
66. MRI of the brain, T1-
weighted sagittal cut.
1, Column of fornix.
2, Corpus callosum.
3, Midbrain.
4, Pons.
5, Cerebellum
67. 1, Column of fornix. 2, Corpus callosum. 1, Column of fornix. 2, Lentiform nucleus.
3, Caudatus nucleus. 4, Hippocampus 3, Corpus callosum. 4, Crus of fornix.
68. MID BRAIN
• Dorsal tectum : 4 colliculi = corpora quadrigemina
• Ventral cerebral peduncles :
ventral crus cerebri – CST
dorsal tegmentum – cranial N nuclei . Both are
seperated by substantia nigra.
(triangular space between two peduncles is
Interpeduncular cistern)
69.
70. • Red nucleus : dorsomedial to S.nigra. It is present at the level of
supr. colliculus .
• Both red nucleus and S. nigra
are hypointense on T2 W MRI.
(both cannot be seen on CT)
• Lower midbrain – laterally ambient
cistern and posteriorly
quadrigeminal cistern.
(Interpeduncular fossa is limited antr.ly
by mamillary bodies)
71.
72. HIND BRAIN
Pons , medulla and cerebellum
PONS
• Axial cuts of lower pons has posterolaterally directed middle
cerebellar peduncles – lateral to which are CP angle cisterns.
• Supr. cerebellar peduncles – at the level of mid pons.
73.
74.
75. MEDULLA
• 3 cm length.
• Ventral - pyramids (b/w median fissure
& anterolat. sulcus).
Lateral to it are olives.
• Dorsal – fasciculus gracilis (M) &
cuneatus (L).
• On axial CT / MRI – pear shaped (lower pons) ;
square shaped on cephalad cuts , at the level of
F of magendie .
76.
77.
78. Pontomedullary junction
Prominent pontomedullary sulcus on each lateral
wall and ventral fissure is replaced by BROADER basilar
sulcus.
79. CEREBELLUM
• Cerebellar cortical ridges = Folia
• On section cerebellum has a tree like config , so known as
‘Arbor vitae’.
80. • Cerebellum – vermis and 2 lobes – divided by para median sulci.
• Deep transverse fissures divide cerebellum into 3 lobes
(on SAGGITAL MRI) :
Antr. – lingula, central lobule, culmen
Postr. – declive, folium, tuber, pyramid, uvula.
Nodule – flocconodular lobe
• Nodule is the most ventral part
seen on axial scans lying postrior to
4th ventricle.
81. From the level of
ponto medullary
junction, occipital
lobe is seen in axial
cuts
82. • Three cerebellar peduncles are present
superior CP – mid brain (brachium conjunctivum)
middle CP – pons (brachium pontis)
inferior CP – medulla (restiform body).
83.
84.
85. COMISSURES OF BRAIN
White matter tracts that cross the midline, connecting the
two cerebral hemispheres.
1. Corpus callosum
2. Anterior commissure
3. Habenular commissure
4. Posterior commissure
5. Supraoptic commissures : Gudden's commissure
Meynert's commissure
86.
87. Corpus callosum
• Parts – rostrum, genu, body, and splenium.
• Forceps minor (frontal) and major (occipital).
• In Saggital sections , it is curved in shape.
88.
89.
90. Anterior comissure
• Myelinated fibers at antr. limit of diencephalon (lamina
terminalis)
• On MRI , seen as convex arc of fibers – useful to locate
perivascular spaces along its lateral aspect.
• Line joining AC--PC is used
as standard reference in
stereotactic surgery.
