(a) It is reported from Muhammad bin Amr bin Ata' that he was sitting with a group of the Companions of the Messenger of Allah (peace and blessings be upon him). Then he mentioned the complete hadith reported from Abu Humayd al-Sa'idi (may Allah be pleased with him), in which the method of the prayer of the Messenger of Allah (peace and blessings be upon him) is described. Abu Humayd (may Allah be pleased with him) said: When the Messenger of Allah (peace and blessings be upon him) raised his blessed head from bowing, he stood up straight until every vertebra of the back returned to its place.
(b) Abd al-Hamid bin Ja'far reported this from Muhammad bin Amr bin Ata'; he said: Every blessed bone of his (peace and blessings be upon him) would return to its place in balance.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2623