Origin.—The origin is fleshy from the mid-anterior surface of the distal part of the tarsometatarsus ending a short distance proximal to the trochlea for digit III.
Insertion.—The flat tendon passes over the trochlea for digit III and attaches to the dorsal surface of the proximal end of the first phalanx of digit III.
Innervation.—The compound nerve formed by the fusion of a branch of the superficial peroneal nerve with a branch of the deep peroneal nerve gives a twig to the proximal end of the muscle.
Individual Variation.—In some cases, the twig arises from the deep peroneal branch alone (which is not joined by the superficial peroneal nerve). The individual variation is insignificant in T. cupido and P. p. jamesi.
M. Extensor Proprius Digiti III (Not found by Hudson, et al.), [Fig. 20]N
T. pallidicinctus and T. cupido
Absent in both species.
P. p. jamesi
This atypical muscle was found in only two legs (P.p. 1L and 4L). The following description applies to P.p. 4L ([Fig. 20]N).
General Description and Relations.—Small but well developed; fleshy part 1½ × 13 mm.; proximal end narrower; on mid-anterior surface of tarsometatarsus between Mm. extensor brevis digiti IV and extensor hallucis longus and mostly proximal to M. extensor brevis digiti III; tendinous distal part superficial to latter; fleshy belly ending immediately distal to proximal end of latter.