(45) باب الاِعْتِدَالِ فِي السُّجُودِ وَوَضْعِ الْكَفَّيْنِ عَلَى الأَرْضِ وَرَفْعِ الْمِرْفَقَيْنِ عَنِ الْجَنْبَيْنِ وَرَفْعِ الْبَطْنِ عَنِ الْفَخِذَيْنِ فِي السُّجُودِ
This hadith has been narrated by Shu'ba with the same chain of transmitters. And in the hidith transmitted by Ibn Ja'far (the words are):
" None of you should stretch out his forearms like the stretching out of a dog."
Reference: Sahih Muslim 493 b
In-book reference: Book 4, Hadith 265
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 998