How could the Sumerian sign for a hand also represent the syllable shu?

The Sumerian sign for a hand could represent the syllable shu due to the adoption of the rebus principle. While the pictograph originally functioned as a logogram representing the concrete object "hand" (Sumerian shu), the rebus principle allowed the sign to evoke the underlying sound form of the word rather than just its meaning.1

Because the Sumerian language was largely monosyllabic, many signs naturally denoted syllables. By using the pictographic shape to represent the phonetic syllable shu in various contexts, the script transitioned from pure word writing to a partial phonetic system. This development enabled the representation of abstract concepts, proper names, and grammatical elements that could not be easily depicted through simple drawings.1