The face is positioned between the palms in prostration, and the hands, knees, feet, forehead and nose are brought into their prescribed posture.
«أُمِرْتُ أَنْ أَسْجُدَ عَلَى سَبْعَةِ أَعْظُمٍ»
Meaning: I was commanded to prostrate on seven bodily parts.
The narration names the face, both hands, both knees and the parts of both feet; the face includes reference to forehead and nose.