Gadow's study (1880) on the ratites included _Struthio_, _Rhea_, and _Casuarius_. Only in _Casuarius_ did Gadow find a branch (IIe) of the sciatic nerve supplying Mm. lumbricalis, adductor digiti II, and abductor digiti II. The two former muscles are typically supplied (as in _Rhea_) by the paraperoneal branch of the tibial nerve; Gadow's branch IIe presumably represents a segregated branch of this nerve. More surprising is his finding that M. abductor digiti II is innervated in _Casuarius_ by both the deep peroneal nerve and branch IIe and in _Rhea_ by branch Ic (paraperoneal branch of tibial nerve). The deep peroneal innervation is typical. Also unexpected is his finding that the posterior division of the femoral nerve gives minute twigs into M. gastrocnemius pars interna in _Struthio_ and _Casuarius_. Since the other terminal branches of this nerve in these birds are nonmuscular, since this muscle is chiefly supplied by other nerves, and since the innervation from the femoral nerve is apparently atypical for most birds, the possibility should be considered that the femoral twigs are sensory rather than motor.
Sudilovskaya (1931), studying _Struthio_, _Rhea_, and _Dromaeus_ (_Dromiceius_), used the same terminology as Gadow except that he designates as branch III Gadow's branch Ic. Sudilovskaya's discussion of the main branches of the sciatic nerve is confusing. He states that in _Struthio_, branches I, II, and III all pass through the tendinous guide loop for M. extensor iliofibularis; this is hard to believe. As near as I can determine, he has mistakenly given the same designation (branch III) to two separate branches (Gadow's Ic and III). There is no problem, however, in determining to which of these two branches he is referring when he is describing the innervation of a particular muscle, since one supplies only muscles of the shank and the other only intrinsic foot muscles. Sudilovskaya found M. abductor digiti II to be innervated by branch III (Ic of Gadow); thus the innervation of this muscle corresponds to that found in _Rhea_ by Gadow. Although M. adductor digiti II had the expected innervation from branch III (paraperoneal branch of tibial nerve) in _Dromaeus_, that muscle was found to be supplied by branch II in _Rhea_. (Gadow, on the other hand, reports a typical innervation for this muscle in _Rhea_.) Sudilovskaya found M. peroneus brevis to be supplied by the deep peroneal branch (in contrast to the superficial peroneal supply that I found in _Tympanuchus_ and _Pedioecetes_). He found M. gastrocnemius pars interna to be supplied in _Struthio_ by twigs of the femoral nerve in addition to its typical innervation from branch II of the sciatic nerve; this agrees with Gadow's findings in the same genus. Sudilovskaya reports that M. gastrocnemius pars externa was innervated by branches II and III in _Struthio_ and _Rhea_ and by branches I and III in _Dromaeus_. (Gadow found only the typical innervation--branch III.)