وَطَيِّ مَحَالٍ كَالْحَنِيِّ خُلُوفُهُ
وَأَجْرِنَةٌ لُزَّتْ بِدَأْيٍ مُنَضَّدِ
Its back is layered and fitted together like the lining of a well, with curves reminiscent of bows; the underside structures of its neck are joined to compact, firmly arranged supporting parts.
Maḥāl refers here to the vertebral segments of the back. Ṭayy evokes the fitted masonry that lines a well; al-ḥaniyy points toward curved bows.
In the second half, ajrinah refers to undersides or parts of the neck, luzzat to being firmly joined, and munaḍḍad to compact layering. The anatomy is understood as a coherent engineered structure, not an assortment of disconnected pieces.