OCR Text |
Show 1883.] ANATOMY OF PHOiNICOPTERUS. 645 4. The semitendinosus is rather narrow ; it arises from the tip of postacetabular ridge of the ilium, and from the fascia between this and the pubis. It is inserted (1) into the tendon intersecting its accessorius ; and (2) into a flat tendon which passes round the accessorius to join the tendon of the semimembranosus. 5. The semimembranosus arises from the hinder end of the ischium, and a small piece of the pubis. Its flat tendon receives, as has already been said, the tendon of the preceding muscle. 6. The accessory semitendinosus arises from the point of insertion into the femur of the great adductors ; it then goes to the tendon already mentioned, which receives on one side the semitendinosus, on the other its accessorius, and finally goes to join the middle head of the gastrocnemius. 7. The ambiens is small; it has the normal relations described by Garrod. 8. There are three glutei, all of which are large. 9. The obturator externus arises from the anterior half of the ischium behind the postacetabular foramen. Its origin is fleshy ; its upper surface is tendinous, covered by a thick and strong aponeurosis. 10. The obturator internus has an oval origin; round its tendon there is, as usual in birds, a single representative of the gemelli. 11. The adductor longus is attached to the ischium behind the obturator foramen ; it is inserted into the linea aspera along the distal three fourths of the femur, the ventral face of the inner condyle, the capsular ligament of the knee-joint, and the head of the tibia. 12. The adductor magnus arises from the external face of the adductor longus ; it is inserted along the outer edge of the middle third of the linea aspera, where it fuses with the accessory semitendinosus. 13. The pectineus arises just internal to the gluteus quartus and is inserted on the inner side of the femur, between the rectus and vastus internus. 14. The quadriceps femoris is made up of a fused rectus and vastus externus, the vastus internus being distinct. The last-named muscle, as well as joining the common tendon at the patella, has a small separate tendon going to the outer side of the tibial crest. 15. The gastrocnemius arises by three heads:-(a) the inner arises from the tendon of the rectus, from the fascia covering the inner surface of the tibialis anticus, and from the cnemial crest of the tibia. It forms a large fleshy belly, which remains distinct from the rest of the muscle till the tendo Achillis. (6) The middle head arises by a flat narrow tendon between the condyles of the femur; it then forms a small belly, joined by the accessory semitendinosus, and then going to the outer head. (c) The outer head has a very short thin tendon arising from the outer condyle of the femur, between the biceps sling and the origin of the flexor perforatus et perforans. The result of this arrangement is that the muscle has a very curious shape, shown in the accompanying woodcut. |