When the Prophet ﷺ bowed, he would keep his back level, and when he prostrated, he would point his fingers toward the qiblah and spread his legs apart.
كان النبي ﷺ إذا ركع بسط ظهره، وإذا سجد وجه أصابعه قبل القبلة، فتفاج.
No references are available.
Bayhaqi (2/113) narrated it from Abu Abbas Muhammad bin Ishaq Thaqafi, who said, our teacher Husayn bin Ali Sadai narrated to us, my father Ali bin Yazid narrated to me, from Zakariya bin Abu Zaida, from Abu Ishaq, from Bara, and he related it.Abu Abbas Muhammad bin Ishaq Thaqafi is Sarraj, the author of the Musnad, though I did not find this hadith in "Hadith Sarraj" printed with the verification of brother Ibn Ukasha. However, I did find it in "Musnad Sarraj" (352) with the verification of Shaykh Irshad al-Haqq Athari.Its chain is hasan due to the discussion surrounding Husayn bin Ali Sadai, though Hafiz said in "Diraya", "Its chain is sahih." I say, he is a disputed narrator. Ahmad said, "There was nothing wrong with him," while Abu Hatim criticized him. Nevertheless, his hadith here can be graded hasan due to the existence of scattered corroborating reports for it.