せすじの 背筋を伸ばす Show inflections LinksSentence search for 背筋を伸ばすSentence search for せすじをのばすKanji details for 背, 筋 and 伸Edit in JMdict Expressions (phrases, clauses, etc.), Godan verb with 'su' ending1. to straighten up one's back (e.g. stand up straight, sit up straight); to hold one's head high Discussions Log in to talk about this word.