Yadāhā is dual, “her two forelegs”; ʿaḍudāhā is also dual, “her two upper forelimbs.” The pronoun -hā refers to the she-camel in both phrases. Fatl shazr operates as a meaningful unit that characterizes the kind of twisting.
Wa-ajnaḥat and the following phrase about her upper limbs must be read with the structural comparison in the second hemistich. Isolated dictionary translations would obscure the relation: two paired limbs, described through two complementary notions of firmness.