The Messenger of Allah ﷺ said: I was commanded to prostrate myself on the seven (bones) and forbidden to fold back hair and clothing. (The seven bones are): forehead, nose, hands, knees and feet. (Using translation from Muslim 490e)  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ «أُمِرْتُ أَنْ أَسْجُدَ عَلَى سَبْعٍ لَا أَكْفِتَ الشَّعْرَ وَلَا الثِّيَابَ الْجَبْهَةِ وَالْأَنْفِ وَالْيَدَيْنِ وَالرُّكْبَتَيْنِ وَالْقَدَمَيْنِ»