Most of the –ma nouns used (sōma, dōma, sēma, aima – вставка моя, V.G.) denote a physical part/effect of the human body, and thus offer material for emotive language. But it does seem as if Sophocles finds the suffix (-ma) peculiarly suitable for the expression of strong emotion, even in contexts where –ma nouns have no direct personal reference.

Long A.A. Language and Thought in Sophocles. A Study of Abstract Nouns and Poetic Technique. University of London. The Athlone Press, 1968. P. 123