Brain lesion

Damage to a region of the brain. An observed deficit can reflect local tissue loss, disconnected pathways or remote dysfunction; preserved performance can reflect redundant routes or compensation. Lesion extent and appropriate sensory and motor controls matter for causal inference.

Brain herniation is displacement of brain tissue across an anatomical boundary under an abnormal pressure relationship. The displaced tissue can compress other structures and vessels. Location and direction of displacement determine the consequences; it is a mechanical process rather than one particular underlying disease.

Hypoxic-ischaemic brain injury is brain damage associated with inadequate oxygen supply and blood delivery. Supply, metabolic demand and duration interact. A loss of oxygenation and a loss of perfusion are related but distinct physiological disturbances.