The Messenger of Allah ﷺ used to prostrate on the fleshy parts of his palms.
كان رسول الله ﷺ يسجد على أليتي الكف.
No references are available.
Ahmad narrated it (18604), and Ibn Khuzayma graded it sahih (639), and from him Ibn Hibban (1915), and Hakim (1/227), and from his route Bayhaqi (2/107), all of them from the hadith of Husayn bin Waqid, who said, Abu Ishaq told us, who said, Bara told me, and he then narrated it. Hakim said, "Sahih according to the standard of the two sheikhs, but they did not include it." Its chain is hasan because of Husayn bin Waqid Marwazi, for his hadith is hasan.