Akkadian

šapūlu, šapullu - upper or inner thigh (CAD Š₁ 492, AHw. 1177)

PS
*šapū/il- - legs (as lower parts of body) (SED I No. 271)

Obviously from Sem. *špl ‘to be low’; reconstruction of a separate Sem. root with an anatomic meaning is tentative since a possibility of an independent development ‘lower part’ > ‘thigh/leg/feet’ in each of the languages cannot be ruled out (note SED I No. 271).