Anatomy - brain

Lies near the temporal pole, between the inferior horn of the lateral ventricle and the lentiform nucleus.
Can be seen on MRI anterior to the hippocampus in the medial temporal lobe

• Has a head, body and tail
• Long thin tail ends in amygdaloid nucleus
• Highly curved and lies within the concavity of the lateral ventricle
o Head projects into the floor of the anterior horn
o body lies along the body of the lateral ventricle
o tail lies in the roof of the inferior horn of the ventricle

Thin sheet of grey matter lying between the putamen (seperated from by external capsule) and insula (seperated from by extreme capsule).

• Above – the diaphragma sella and above this the suprasellar cistern with the optic chiasm anteriorly and the circle of Willis
• Below – the body of sphenoid and the sphenoid sinus
• Laterally – the dura and the cavernous sinus and its contents

ROSTRUM: first part extending from the anterior commissure/ lamina terminalis.
GENU: most anterior part where bends sharply backwards. Fibres called forceps minor arch into frontal cortex
BODY: largest mass of fibres extending laterally as the tapetum
SPLENIUM: thickened posterior end with forceps major extending into occipital cortexes

1. Pericallosal arteries from ACA
2. Posterior pericallosal arteries from PCA,.
3. 80% of patients have supply via either subcallosal artery or median callosal artery from ACA.

o PICA (vertebral arteries) supply the inferior vermis and inferior parts of hemispheres
o AICA (basilar artery) supply anterolateral aspect of the undersurface of the hemisphere
o Superior cerebellar arteries (basilar artery) supply superior aspect of cerebellum

• Corpus striatum – caudate and lentiform nuclei (putamen and globus pallidus)
• Amygdala (limbic system)
• Claustrum

Clinoid process
Petrous temporal bone
Internal surface of occipital bone

Transverse sinus

Superior Petrosal sinus

S shape continuation of transverse sinus within posterior cranial fossa -> IJV

Formed by the union of the inferior sagittal sinus and great cerebral vein. Runs inferoposteriorly along the line of attachment of the cerebral falx to cerebellar tentorium joining confluence of sinuses

Between splenium of corpus callosum and superior surface of cerebellum.
Extends from 3rd ventricle to great cerebral vein.

Anterior cerebral arteries are in contact with the under surface of the rostrum, arch over the front of the genu and are carried backwards above the body.
Falx cerebri – superior to body
Lateral ventricles – roof formed by inferior surface of CC.
Cingulate gyrus – lateral to CC separated by callosal fissure
Inferior surface fused with septum pellucidum anteriorly, and joined to fornix and its commissure posteriorly.

• Lacrimal gland
• Globe
- Transparent anterior cornea
- Opaque posterior sclera
• Extraocular muscles
- 4 rectus muscles arise from the annulus of Qinn arising from the lower border of the Superior Orbital Fissure (SOF)
- Inferior oblique arises from the floor of the orbit
- Superior oblique arises from the sphenoid bone -> around troclea (pulley attached to superolateral orbit) -> globe
• Optic nerve
- Through optic canal -> optic disc
• Ophthalmic artery
- Through optic canal -> central retinal artery -> eye and branches to orbital contents/ eyelid
• Venous drainage
- Superior ophthalmic vein (union of angular and supraorbital) + Inferior optic vein -> Drain into cavernous sinus via SOF

• Inferior to the lateral fissure (Sylvian) and parietal lobe
• Anterior to the occipital lobe
• Seperated from cerebellum inferiorly by falx cerebelli
• Lateral to splenium (corpus callosum)

Receives: superior and inferior ophthalmic veins, sphenoparietal sinus and superficial middle cerebral vein

Drain into: superior and inferior petrosal sinuses -> sigmoid sinus -> IJV

Area where venous drainage is via facial vein -> angular vein -> superior ophthalmic vein -> cavernous sinus.
Risk of spread of superficial infection (predominately sinus)

1. Hypoplastic PCA (22%)
2. Large PCOM with small proximal PCA so that supplied predominantly by ICA (6-40%) - foetal PCA
3. Hypoplastic A1 of ACA with supply from the other side (30%)
4. Hypoplastic anterior communicating (3%)
5. Fused ACA (azygous ACA)

Lateral: internal capsule and lentiform nucleus beyond. Body and tail of caudate nucleus.
Medial: 3rd ventricle
Superior: lateral ventricle
Inferior: midbrain
Anterior: interventricular foramen (of Munro)

- largest part of diencephalon (prosenchephalon/ forebrain)
- paired ovoid bodies of grey matter
- relay nuclei of sensory pathways
- massa intermedia in 60% joining the thalamus
- posteroinferior geniculate bodies: lateral attaches to superior colliculus (vision) medial to inferior (auditory)

Thalamostriate branches of the PCA.

T1 axial brain
1, Cerebral peduncle.
2, Middle cerebral artery.
3, Midbrain.
4, Cerebral aqueduct.

1, Third ventricle.
2, Sylvian fissure.
3, Anterior commissure.
4, Pineal gland. 5, Choroid plexus (atrium).
6, Calcarine sulcus.

T1 weighted, coronal
1, Hippocampus.
2, Anterior commissure.
3, Fornix (crura).
4, Lateral ventricle.
5, Sylvian fissure.
6, Middle temporal gyrus.
7, Inferior temporal gyrus.

1, Hippocampus.
2, Caudate nucleus.
3, Corpus callosum.
4, Lateral ventricle.
5, Third ventricle.
6, Interpeduncular cistern

1, Fourth ventricule.
2, Superior cerebellar peduncle.
3, Lateral ventricle.
4, Fornix.
5, Colliculus.
6, Cerebellar hemisphere.

1, Cerebellar hemisphere.
2, Lateral ventricle.
3, Cingulate sulcus.
4, Cingulate gyrus.
5, Choroid plexus.

1, Internal cerebral veins.
2, Vein of Galen.
3, Straight sinus.
4, Superior sagittal sinus.

1, Superior sagittal sinus.
2, Inferior sagittal sinus.
3, Straight sinus.
4, Sinus confluence.
5, Vein of Galen.
6, Internal cerebral vein

T2-weighted, coronal section.
1, Sphenoidal sinus.
2, Anterior clinoid process.
3, Lateral ventricle.
4, Anterior cerebral artery.
5, Optic nerve

T2-weighted, coronal section.
1, Sphenoidal sinus.
2, Internal carotid artery. 3
, Temporal pole.
4, Middle cerebral artery.
5, Lateral ventricle.
6, Septum pellucidum.
7, Anterior cerebral artery.
8, Optic nerve.
9, Anterior clinoid process.

T2-weighted, coronal section.
1, Pituitary gland.
2, Infudibulum.
3, Optic chiasma.
4, Lateral ventricle.
5, Anterior cerebral artery.
6, Middle cerebral artery.
7, Sphenoidal sinus.

Axial multidetector CT image.
1, Turbinate.
2, Maxillary sinus.
3, Lateral lamina of pterygoid process.
4, Rhinopharynx.
5, Atlas.
6, Pterygomaxillary fissure

- part of the limbic system (including cingulate, splenial and parahimppocampal gyri, hippocampus and dentate gyrus
- efferent parthway from hippocampus to mamillary bodies
- anterior parallel columns, single body, posterior parallel crus and fimbrae

Relations
- inferior to splenium of CC and septum pelucidum
- anterior to thalamus
- form anterior wall of interventricular foramen

Posterior: Inferior hypophyseal arises in cavernous sinus
Anterior + infundibulum: superior hypophyseal forms portal capillary system

Venous drainage to cavernous sinus