Enlarged perivascular (virchow robin) spaces?
- Cryptococcus (gelatinous pseudocyts, do not enhance) - Mucopolysaccharidoses (hunters, Hurlers) - Atrophy VR don't contain CSF
Progression: inferior to superior, posterior to anterior, central to peripheral Subcortical white matter is last to myelinate Brainstem and posterior limb of internal capsule are myelinated at 36 weeks
Corpus Callosum Development?
Front to back (but the rostrum is last)
Immature Myelin Appearance?
Higher water content- brighter on T2 and darker on T1 Mature myelin- bright on T1 and T2 dark T1 (1 yo) changes proceed T2 changes (2yo)
Paranasal sinus formation?
Maxillary -> Ethmoid -> Sphenoid ->Frontal
CN V3, accessory meningeal artery
Superior Orbital Fissure
CN 3,4, V1, and CN 6
Inferior orbital fissure
Middle meningeal artery (spine contains meninges)
Jugular vein, CN 9, CN 10, CN 11
CN 2 and opthalmic artery
What runs in the cavernous sinus
CN 3, 4, V1, V2, CN 6 (CN 2 and CN V3- do not run in)
What nerve is adjacent to the carotid artery in the cavernous sinus and is not within the wall?
Branches of external carotid?
Some administrators like fucking over poor medical students Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior Auricular Maxillary Superficial temporal
Internal Carotid Artery Branches?
C2- petrous C3 - Lacerum C4- Cavernous (site of CC fistulas) C5- Clinoid ( aneurysm can compress the optic nerve at this level) C6-Ophthalmic (origin at the dural ring- intrdural) C7- Communicating terminal (aneurysm can cause CN III palsy)
PCOM is as large or bigger then the P1 segment PCOM is superior and lateral to CN 3 (as opposed to superior and medial in normal anatomy)
Deep Cerebral Veins
Basal Vein of Rosenthal Vein of Galen Inferior Petrosal Sinus
Superficial Cerebral Veins
Vein of Trolard (drains into superior sagittal sinus) Vein of Labbe (drains into the transverse sinus) Superficial Middle Cerebral Veins Superior Cerebral Veins
CN III Palsy
Terminal Aneurysm Aneurysm of the PComm Artery
CN 6 palsy
Increased intracranial pressure
Sagging of midbrain meningeal enhancement distension of dural venous sinuses
Empty Sella Optic Hydrops Papilledema
Intracellular Na/K pump
Obstructive: Non-communicating- involves the ventricular system Communicating-Involves the villi/arachnodi granulations Non-obstructive: Increased production of CSF- choroid plexus papilloma
Effaces ipsilateral suprasellar cistern first Duret hemorrhage from basilar artery perforators
- Relapsing and remitting is most common type - Acute plaques should restrict diffusion - Tumefactive- incomplete ring enhancement Marburg- childhood variant, fulminant, rapid demise
Post-viral/vaccination T2 bright lesions, which enhance in a nodular/ring like fashion Typically don't involve the collosal septal interface