Page 547 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Neurology aNd Special SeNSeS ` neurology—AnAtomy And Physiology Neurology aNd Special SeNSeS ` neurology—AnAtomy And Physiology SecTioN iii 503

Circle of Willis System of anastomoses between anterior and posterior blood supplies to brain.

ACom Anterior
communicating Optic chiasm
A2
Anterior
ACA
cerebral Internal carotid ICA
A1
ACA
Anterior
circulation MCA Middle Lenticulo- MCA
ACA cerebral striate PCA
ICA M1 OF
MCA Posterior
PCom Anterior
Posterior communicating choroidal BA
circulation P2 P1
Posterior PCom
PCA cerebral ICA
ECA
CCA VA
Superior
SCA Pontine
cerebellar Brachio-
cephalic
Sub-
clavian
Anterior inferior
AICA Basilar BA
cerebellar
Aorta
Posterior inferior Vertebral VA
PICA cerebellar OBLIQUE-LATERAL VIEW
INFERIOR VIEW
Anterior spinal ASA

Dural venous sinuses Large venous channels A that run through the periosteal and meningeal layers of the dura mater.
Drain blood from cerebral veins (arrow) and receive CSF from arachnoid granulations. Empty
A
into internal jugular vein.
Venous sinus thrombosis—presents with signs/symptoms of  ICP (eg, headache, seizures,
papilledema, focal neurologic deficits). May lead to venous hemorrhage. Associated with
hypercoagulable states (eg, pregnancy, OCP use, factor V Leiden).

Superior sagittal sinus
(main location of CSF return
via arachnoid granulations)

Inferior sagittal sinus
Great cerebral vein of Galen Superior ophthalmic vein
Sphenoparietal sinus
Straight sinus
Cavernous sinus
Confluence of the sinuses
Sigmoid sinus
Occipital sinus
Jugular foramen
Transverse sinus
Internal jugular vein

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