Lucid interval is most commonly seen in -

Ans. is 'a' i.e., Acute extradural hemorrhage Acute Extradural hematomao Accumulation of blood b/w skull & durao Bleeding is from a branch of middle meningeal artery* in 90% of caseso Trauma is usually severe associated with concussion and skull fracture.o With arterial bleeding, the hematoma expands rapidly, and symptoms appear within hours after injuryo The clinical course is acute -# After a head injury often associated with a variable period of concussion - the patient appears normal for several hours (lucid interval).# After this lucid interval, the pt. develops evidence of increased intracranial pressure with headache, vomitting, altered consciousness, and papilledema.# Tentorial herniation rapidly follows, with occulomotor nerve palsy (pupillary inequality appears first, followed by failure of reaction to light k/a Hutchinson's sign and pyramidal tract compression.# Compression of the brain stem follows, resulting in changes in heart rate, blood pressure and respiration.# Coma and death rapidly ensue in untreated cases.o Its an emergency and requires prompt diagnosis & surgical evacuation of the extradural blood collection.