Ṣulb refers to the back or its firm central structure. Aʿjāz, the plural of ʿajuz, names hind parts of a body, while kalkal denotes the chest or heavy front portion. All three belong to the vocabulary of physical anatomy.
Tamaṭṭā evokes a body stretching itself. Ardafa means bringing one part behind another; nāʾa communicates bearing or sagging under weight.
The result is a complete figure in which abstract duration acquires a back, rear, and chest. Translating all this simply as “the night lasted a long time” would remove the layered figurative structure of the original.