their dead and wounded

I don't know why this usage is proper. My grammar book tells me that if you want to use an adjective as a noun, you should put "the" in front of the adjective, that is, only "the dead and wounded" is right, but "their dead and wounded" is wrong.

Context:
Early in the day, the Marines halted most offensive operations in Falluja so that talks could be held with a delegation of sheiks, and the city's residents could collect their dead and wounded, but there were still reports of sporadic fighting there and elsewhere. Two American soldiers died in separate incidents, the military reported.

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For example:
If there are just some wounded men there, saying "their wounded" sounds so weird, but "the wounded" works.