Brain Herniation: Vascular Compression, Cranial‑Nerve Involvement, and Imaging Signs

Vascular Complications

Subfalcine herniation can compress the anterior cerebral artery, potentially causing infarction in its vascular territory. 1
Subfalcine herniation can compress the anterior cerebral artery, potentially causing infarction in its vascular territory. 2

Uncal (descending transtentorial) herniation displaces the medial temporal lobe through the tentorial opening and may compress the third cranial nerve, producing ipsilateral pupillary dilation and a fixed pupil. 1
Uncal (descending transtentorial) herniation displaces the medial temporal lobe through the tentorial opening and may compress the third cranial nerve, producing ipsilateral pupillary dilation and a fixed pupil. 2

Upward (ascending transtentorial) cerebellar herniation occurs when posterior‑fossa contents herniate upward through the tentorial opening. 3
Space‑occupying cerebellar strokes can precipitate upward cerebellar herniation, leading to brain‑stem compression. 4
Space‑occupying cerebellar strokes can precipitate upward cerebellar herniation, leading to brain‑stem compression. 3
Downward tonsillar herniation (transforaminal herniation or cerebellar pressure coning) may result from posterior‑fossa pathology and can be fatal in the setting of space‑occupying cerebellar strokes. 4
Downward tonsillar herniation (transforaminal herniation or cerebellar pressure coning) may result from posterior‑fossa pathology and can be fatal in the setting of space‑occupying cerebellar strokes. 3

Computed tomography and magnetic resonance imaging reveal characteristic radiologic signs of herniation, including midline shift, compression of basal cisterns, ventricular compression, and displacement of specific brain structures according to the herniation type. 1
Computed tomography and magnetic resonance imaging reveal characteristic radiologic signs of herniation, including midline shift, compression of basal cisterns, ventricular compression, and displacement of specific brain structures according to the herniation type. 2