The purpose of this educational exhibit is: to explain the pathophysiology underlying brain herniations; to delineate the spectrum of brain herniations and their differential diagnosis; to describe clinical and imaging features of brain herniations.

Brain herniation represents a shift of brain parenchyma across anatomical boundaries formed by intracranial bony ridges and dural folds (falx cerebri, tentorium cerebelli, falx cerebelli and the diaphragm sellae). Brain herniation occurs when an expanding mass lesion including tumors, hematomas, infarctions, infection, or haemorrhage exhausts the limited capacity of intracranial cavity (Table 1). Development of herniation due to mass effect depends upon many factors including patient age; size, location and progression rate of mass lesion; pressure gradient between mean blood pressure, cerebrospinal fluid and brain...

The skull is a rigid bone structure occupied by the brain, the cerebrospinal fluid, the blood vessels and the meninges, with a single wide opening (foramen magno).Meninges consist of three membranous connective tissue layers: dura mater, arachnoid mater and pia mater. The dura mater is a thick fibrous membrane consisting of two laminae: the outer dural layer adheres intimately to the periosteum of the skull; the inner dural layer forms voluminous folds that deepen in the brain by dividing the cranial cavity into various compartments...

The knowledge of radiological findings occurring in brain herniations is essential to make an early diagnosis and assessment.

Radiodiagnostic and Radiotherapy Unit – University Hospital “Policlinico-Vittorio Emanuele”, Catania, Italy, Via Santa Sofia 78 – 95123 Catania

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