knock myself out = to lose consciousness, to pass out?

[Saneta]

English Language Tests, Intermediate level

ESL/EFL Test #194 "Phrasal Verbs (H to L)", question 8

When I hit my head on the cupboard, I almost ..........

(a) knocked myself out
(b) knocked myself in
(c) knocked myself

English Language Tests, Intermediate level

ESL/EFL Test #194 "Phrasal Verbs (H to L)", answer 8

When I hit my head on the cupboard, I almost knocked myself out.

Correct answer: (a) knocked myself out
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knock myself out= to lose the consciousness, to pass out?

thanks

[Beeesneees]

Yes, but the article is not used with 'consciousness'.
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Cheers m' dears!