يَخْرُجُ مِنۢ بَيْنِ ٱلصُّلْبِ وَٱلتَّرَآئِبِ
Yakhruju mim bainissulbi wat taraaa'ib
then he emerges from between the backbone and breastbone:
issuing from between the backbone and the ribs.
The word for the ribs here occurs at this one place in the whole Qur'an, and commentators have read the pair more than one way: the man's backbone and the woman's ribs, or the anatomy of a single body. The verse closes an argument from origin — attend to where you began, and the claim made in the next line about being brought back stops sounding far-fetched.