The Messenger of Allāh (May Allāh praise him and Peace be upon him) would put them straight up, not together but not very far apart, when he raised his hands, bringing them up to shoulder height. Sometimes he would lift them higher to the height of the bottoms of his ears. In one narration, it says “To the tops of his ears”. [Ṣifat al Ṣalāt (Description of Prayer), by Sheikh Al-Albānī, p.87]