Transtentorial herniation

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Transtentorial ( uncal) herniation:

Image source: Wikipedia

 

Herniation of the parahippocampal uncus(medial temoral lobe) - 1 in the above image.

Can occur after head trauma

Symptoms:

Ipsilateral hemiparesis( contralateral crus cerebri compression: Kernohan's notch)

Compression of ipsilateral occulomotor nerve ( CN III) by uncus causes:

Mydriasis( early: parasympathetic loss)

Ptosis 

Strabismus( down and out)

Contralateral homonymous hemianospia(Ipsilateral posterior cerebral artery compression)

Altered consciousness and coma(Reticular formation compression)