Is it permissible in congregational prayer to bring the hands close to the body during prostration, even though the Sunnah is to keep them apart, due to lack of space?

It is Sunnah (definition) for the worshiper to separate his arms from his sides during prostration and bowing, and not to press them together. This is indicated by the actions of the Prophet, peace and blessings be upon him, and the sayings of the scholars. The wisdom behind this separation is that each limb appears distinct on its own, as if the single person in his prostration is a multitude. This separation is a Sunnah and not obligatory, by scholarly consensus. It is conditional on not causing harm to neighboring worshipers or difficulty for the worshiper. If it harms his neighbor, then it is obligatory to abandon it, because harm is forbidden. And whoever abandons a Sunnah to prevent harm will be rewarded for it, and he may be credited with the reward of the Sunnah if his intention was to perform it were it not for the impediment.