122 THE VOYAGE OF H.M.S. CHALLENGEE. 



The flexor perforatus of the outer toe is the most superficially placed of the three. It 

 becomes distinct from the common mass one inch below the knee joint, and is here joined 

 by a portion of the tendon of the ambiens muscle. The muscle terminates on a single 

 tendon, which, after passing through a canal in the fibro-cartilage behind the ankle joint, 

 divides into two slips, one of which is inserted into the base of the second phalanx of 

 the fourth or outer toe, while the other, after being slit to allow of the transmission of the 

 tendon of the flexor perforans, is inserted into the base of the third phalanx of that toe. 



Action. — The muscle flexes the outer toe. 



Relations. — Concealed superficially by the outer head of the gastrocnemius, it rests 

 upon the flexor perforatus digiti medii. 



Nerve supply. — A branch of the sciatic nerve. 



Variations. — In Pygosceles tceniatus the tendon of insertion of this muscle gives off an 

 additional slip, which is inserted into the base of the fourth phalanx of the outer toe. In 

 Spheniscus mendiculus, on the other hand, the tendon divides into two slips, both of which 

 are inserted into the base of the second phalanx. Between these the tendon of the flexor 

 perforans passes forwards to its insertion. 



5. Flexor perforatus et perforans digiti interni. 



Le flechisseur perforant et perfore (part of), Vicq d'Azyr, 1774, p. 512, Xo. 4. 



Der durchhoJiHe Bmger der innem Zdie, "Wiedemann, p. 102. 



Der durcMiolirte Beuger der innem ZeliP, Tiedemann, p. 341, No. 2. 



Flechisseur perforant et pcrforr (part of), Cuvicr, voL i. p. 396. 



Muscle No. 1 (part of), Meckel, vol. vi. p. 113. 



Flexor perforatus (part of), Eeid, p. 144. 



Flexoi- perforatus of the inner toe, Owen, p. 38. 



Flechisseur perf are, couche superficielle (part of), Gervais and Alix, p. 37. 



Attachments. — The flexor perforatus et perforans of the inner toe arises from the 

 posterior border of the tendon of insertion of the extensor cruris muscle, as well as from 

 the tendon of origin of the outer head of the gastrocnemius. The muscle ends on a 

 delicate tendon, which, after passing through a special canal in the fibro-cartdage behind 

 the ankle joint, is inserted by means of two slips into the base of the second phalanx of 

 the inner toe. Between these slips the tendon of the flexor perforans to this toe passes 

 onwards to its insertion into the last phalanx. 



Action. — This muscle flexes the inner toe. 



Relations. — The muscle lies between the outer head of the gastrocnemius behind, and 

 the origin of the flexor perforans et perforatus in front. It rests on the deeper portion 

 of the flexor perforatus. 



Nerve supj^ly.—A direct branch of the sciatic nerve. 



Remarks. — According to Gervais and Alix, this muscle in Eudyptes chrysolophus takes 



