Cerebral Venous System

Cerebral Sinuses and Veins

There are 11 venous sinuses in total, between periostial and meningeal layers of dura.

Veins of significance include Thalamostriate, Superior Anastomotic Vein (of Trolard), Internal Cerebral Vein, Great Cerebral Vein (of Galen), Basal Vein (of Rosenthal), Inferior Anastomotic Vein (of Labbe), transverse vein, Middle Cerebral Veins (of Sylvius)- Deep and Superficial, Anterior cerebral vein, 


Right transverse sinus is usually dominant and typically receives superficial blood- via continuation of SSS; left TS typically drains deep brain 




NB inferior petrosal sinus sampling (to measure ATCH levels) is a clue that this drains pituitary.

Veins are located in subarachnoid space and divided into superficial and deep systems. 

Superficial Veins


Trolard, Labbe and Sylvius (superficial) all meet up.

Visual Pathways

Visual Pathways 




Blue arrows indicate Meyer's Loop.




Optic nerve is developed from the optic vesicle. 
Originates from retinal ganglion cell axons, enters the cranial cavity via optical canal, passing through tendinous ring annulus of Zinn. 





"2, 3 n 6" pass within the annulus, n being nasociliary nerve (i.e. V1 branch).



Meyer's loop is anterior, inferior and temporal; central bundle abuts lateral ventricle; the dorsal bundle is superior and parietal (Baum's loop). Meyer's loop produces pie in the sky deficit.

NB Nasal fibres cross at the chiasm, temporal don't (you cross your eyes at your nose).




This demonstrates the geniculate pathway conscious visual processing (incorporating the LGN of the thalamus)
There are also extrageniculate pathways, which project to: pretectal nucleus (midbrain- pupillary reflexes), superior colliculus (midbrain- coordinated reflexive head and eye movements), suprachiasmatic nucleus (hypothalamus- circadian cycles).

Cranial Projection and Association Tracts and Limbic System

Bundles implies long association fibres








Corpus callosum fibres








VA- ventral anterior
VL - ventral lateral




NB Lentiform nucleus = GP + putamen

Tegmentum (Lat- Covering). Forms floor of midbrain cf.
Tectum (Lat- Roof). Forms roof of midbrain.
Stria (Lat- Stripe)
    Fasciculus (Lat- Bundle)
    Tapetum (Lat- Tapestry/rug)
    Habenula (Lat- reins). Denotes stalk of pineal gland and neighbouring neurons.








Resembles a tapestry; the carpet of the brain. Primarily formed by decussating fibres of the splenium.

Septal nuclei are by septum pellucidum. Role in pleaseure/reward like Nucleus Accumbus.


Limbic System- a ring of memory and emotion (like a wedding ring).







Simplified:





Deontes a conerstone of memory processing/consolidation





Indusium (tunic/shirt) griseum is membranous layer of grey matter which covers the corpus callosum.

Cavernous Sinus

Cavernous Sinus Anatomy







All are in lateral wall except V1
From superior to inferior III, IV, V1, V2.






Coronal scan through the cavernos sinus. MR contrast-enhanced FIESTA sequence. a, oculomotor nerve; b, trochlear nerve; c, abducens nerve; d, ophthalmic nerve; e, maxillary nerve; f, internal cerebral artery; cavernous segment; g, right optic nerve; h, pituitary gland

Middle Cerebral Artery

Middle Cerebral Artery:

Territory:



Supplies most of lateral surface of hemisphere, part of internal capsule (posterior part of anterior limb and anterior part of posterior limb) and basal ganglia.

Origin:


Segments:





M1- ICA to Sylvian fissure (horizontal or Sphenoidal)
M2- Sylvian (within fissure; also Insular) post bifurcation into superior & inferior divisions. 
M3- Opercular: Top of fissure to cerebral cortex
M4- Cortical (cortical surface branches)




B

Branches:
NB superficial and deep

M1
Lateral lenticulostriate A. (NB ACA is the more medial vessel)

M2 (NB superior and inferior divisions) 
Branches supply temporal lobe and insular cortex, parietal lobe, inferolateral frontal lobe via:

Superior:
Lateral frontobasal A.
Prefrontal sulcas A.
Pre-Rolandic (Precentral) and Rolandic (central) sulcal A.

Inferior:
3 temporal branches (anterior, middle and posterior)
Branch to angular gyrus
2 parietal branches (anterior, posterior)


2-7 appear to be exclusively MCA branches. 1 shared with ACA. 8 PCA also.





M3 and M3
The above branches will have M3 and M4 portions

Anterior Cerebral Artery

Anterior Cerebral Artery

Territory:



Supplies most of medial surface of cerebral cortex (anterior 3/4), frontal pole and anterior portions of corpus callosum.
Perforating branches supply anterior limb of the internal capsule, inferior portions of caudate head and anterior globus pallidus.

Infarction will potentially cause (mainly) lower limb weakness, incontinence, abulia/motor aphasia, frontal lobe symptoms.


Origin


Segments



A1: ICA bifurcation to Acomm (horizontal)
A2: Acomm to origin of CMA around rostrum/genu junction (vertical)
A3: Genu to body of CC (proximal pericallosal)
A4/A5: Continuation of distal pericallosal (directly posterior)



NB angiographic sylvian point = apex of fissure sf. skull sylvian point a surface marking for fissure 3cm behind superior portion of zygomatic process








Branches

A1
Medial lenticulostriate A.
AComm A.

A2
Recurrent artery of Hubner (= medial striate A.). Supplies head of caudate and anterior limb of IC. (Can be A1 branch)
Orbitofrontal A.
Frontopolar A.

A3
Callosomarginal A. (in cingulate sulcus)
Pericallosal A.
Anterior (internal) frontal A.
Middle (internal) frontal A.
Posterior (internal) frontal A.
Paracentral A.


NB Striatum =  Caudate + IC + lentiform nucleus (which = putamen + GP).

Scalp Arterial Supply

Scalp Blood Supply 



Occipital artery further demonstrated