Definition of Coma

Coma: A state of deep, unarousable unconsciousness. A coma may occur as a result of head trauma, disease, poisoning, or numerous other causes. Coma states are sometimes graded based on the absence or presence of reflexive responses to stimuli.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=2803
Last Editorial Review: 3/19/2012