I was commanded to prostrate on seven bones: the forehead - and he pointed to his nose - the hands, the knees, and the toes. [Sahih/Authentic] - Al-Bukhari and Muslim

"«أُمِرْتُ أن أَسْجُدَ على سَبْعَةِ أَعْظُمٍ: على الْجَبْهَةِ -وأشار بيده إلى أنفه- واليدين، والرُّكْبَتَيْنِ ، وأطراف القدمين». [صحيح.] - [متفق عليه.]"