عَنِ ابْنِ عَبَّاسٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «أُمِرْتُ أَنْ أَسْجُدَ عَلَى سَبْعَةِ أَعْظُمٍ عَلَى الْجَبْهَةِ وَالْيَدَيْنِ وَالرُّكْبَتَيْنِ وَأَطْرَافِ الْقَدَمَيْنِ وَلَا نَكْفِتَ الثِّيَاب وَلَا الشّعْر»

Ibn ‘Abbas reported God’s Messenger as saying, “I have been commanded to prostrate myself on seven bones

the forehead, the hands, 1 the knees, and the extremities of the feet, 2 and not to fold back the clothing or the hair.”1. i.e. the palms.2. i.e. the toes.(Bukhari and Muslim.)