124 THE VOYAGE OF H.M.S. CHALLENGER. 



Attachments. — The peroneus longus is situated on the outer side of the leg. It is 

 attached by means of a delicate fascia to the lower border of the outer side of the patella. 

 and through the intervention of a strong aponeurosis to the whole length of the outer 

 border of the fibula. The muscular fibres give place to tendon above the ankle joint. 

 This tendon, as it passes along the outer side of the ankle joint, gives off a flattened 

 expansion which is attached to the fibro-cartilage behind that articulation, and thereafter 

 divides into two slips. Of these, one passes to the sole of the foot and unites with the 

 tendon of the flexor perforatus to the middle toe, while the other passes onwards to be 

 inserted into the penultimate phalanx of the outer toe. 



Action. — This muscle abducts the foot at the ankle joint. Through its insertion 

 into the outer toe it expands the foot by separating the outer from the remaining toes. 

 By its connection with the flexor perforatus it assists in flexing the middle toe. 



Relations. — The muscle lies between the anterior head of oriffin of the gastrocnemius 

 in front, and the superficial origin of the flexor perforatus behind. It rests upon and 

 conceals the upper portion of the tibialis anticus. 



Nerve supply. — A branch from the anterior tibial nerve. 



8. Flexor px^rforans digitorum. 



FlecMsseur peiforant, Vicq d'AzjT, 177-t, p. 512, No. 5. 



Der zweikopfige Muskel, Merrem. 



Der dreispaltige tiefe Zehenbeuger, Wiedemann, p. 104. 



Der dreispaltige tiefe Zehenheuger, Tiedemann, p. 343, No. 5. 



Le troisienie long Jteehisseur, Meckel, vo]. vi. p. 120. 



Flechisseurs perforans, Cuvier, vol. i. p. 396. 



Flexor perf or ans digitorum, Owen, p. 40. 



Flexor perforans, Reid, p. 144. 



Long flechisseur du pouce and flechisseur profond, Gervais and Ali.x, p. 35. 



Attachments. — The flexor perforans arises by two distinct heads of origin. Of these 

 the Jirst, which undoubtedly corresponds to the flexor longus hallucis of the majority of 

 birds, is attached along with the flexores perforati digiti interni, digiti medii, and 

 digiti externi to the depression on the jDosterior surface of the femur immediately above 

 the condyles. A small portion of this head is distinct from the common muscular mass, 

 and arises above the external condyle of the femur. The first head has no connection 

 with the tendon of the ambiens. It separates from the common muscular mass opposite 

 the junction of the upper and middle thirds of the tibia. Its tendon of insertion, after 

 passing through a canal in the fibro-cartilage behind the ankle joint terminates by 

 dividing into three slips, which unite with those derived from the tendon of insertion of 

 the second head opposite the base of each of the anterior toes. The second head of the 

 flexor perforans arises from the upper three-fourths of the posterior surface of the tibia 



