The midfielder was forced off on a stretcher in the first half of the match but managed to complete the game.
Ramsey suffered a deep gash to his calf which required Arsenals medical team to staple the wound together as a temporary solution.
And following the match, Ramsey showed Arsenal fans the severity of the injury in his post on Instagram.
Arsenal were made to sweat in Moscow despite heading into the second leg with a comfortable 4-1 advantage.
CSKA had scored twice by the 50th minute and were pushing for a third goal before Danny Welbeck struck to swing the tie back in Arsenals favour.
Ramsey then struck in injury time as he raced on to Mohamed Elnenys through ball and cooly chipped Igor Akinfeev.
Arsenal are now in the Europa League semi-final draw, which takes places at 1pm on Friday, and Arsene Wengers side could face Atletico Madrid, Marseille or Red Bull Salzburg.
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