lucid interval 

NEUROLOGY

A period (allegedly) preceding the loss of consciousness and coma in patients with subdural and epidural haematomas and intracranial oedema, during which a patient is (allegedly) alert and oriented enough to get in a car after a traumatic event and drive to hospital.

Note: Whilst this phenomenon is well-described in the literature and a favourite for medical student exam questions, it is so rarely seen in clinical practice, that it is almost urban legend 

Synonyms Latent interval, latent period, lucid period 

Reference Knight B, Forensic Pathology, E Arnold, 1996