Sayyidah Maymunah (may Allah be pleased with her) said: When the Prophet (peace and blessings be upon him) prostrated, he kept such a distance (between his arms and body) that if a small animal had wanted to pass beneath him (peace and blessings be upon him), it could have passed.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20356