Akkadian

ḫallu - crotch, region between the thighs; the hind legs of animals (CAD ḫ 45, AHw. 312)

Akk. ḫ- < *ḥ-

PS
*ḥa/ul(l/y)- - spinal column with thigh bones (SED I No. 114)
Semantically and phonetically not without difficulties.