OCR Text |
Show 3 1 2 MR. R. H. BURNE ON THE [Apr. IB, Pubi-ischio-femoralis externus (text-figs. 65, 66. 14).-Origin : from the whole ventral surface of the pubis and epipubis between the insertion of the epipubic part of the rectus abdominis and the origin of the pubi-femoralis and the obturator foramen; from the ventral surface of the ischium between the obturator foramen and the mid-line; and from the dorsal surface of the ischium and the root of the ilium. Insertion : upon the tuberosities of the femur, just distal to the posterior third of the neck. The part of this muscle that arises from the dorsal surface of the ischium and from the ilium is probably the representative of Gadow's pubi-ischio-femoralis posterior. This muscle, with the pubi-ischio-femoralis internus and the ilio-femoralis, forms a thick continuous muscular sheath around the hip-joint. Extensor longus digitorum (text-fig. 67. 16).-Origin: from the external condyle of the femur covered by the insertion of the extensor ilio-tibialis. Insertion : by tendinous expansion to the extensor surface of metatarsals IV. and V., in conjunction with the peroneus; by tendinous slips between each of the four inner toes on the level of the metatarso-plialangeal joints; and by a strong tendon to the inner margin of the head of the first metatarsal. The insertion is less definite than that described for this muscle in other Chelonia. Tibialis anticus (text-figs. 65 & 67. 17).-Origin: from the upper two-thircls of the inner (radial) margin of the radius. Insertion: upon the extensor surface of the head of metatarsus I. and also by a tendinous expansion to the fibrous tissue on the flexor surface of the ankle. Peroneus (text-fig. 67. 18).-Origin: from the distal half of the extensor surface of the fibula and from the extensor surface of the fibular side of the tarsus. Insertion: upon metatarsals IV. and V. The radial side of this muscle is continuous with the deeper parts of the extensor longus digitorum. Gastrocnemius (text-fig. 65. 20).- Origin : from the inner condyle of the femur and from the inner and flexor surfaces of the shaft of the tibia, around the insertion of the pubi-tibialis. At the heel the muscle is transformed into a dense sheet of fibrous tissue, from which arise in the sole of the foot the superficial (perforated) flexors of the digits. The gastrocnemius has also direct attachments to the base of metatarsal I. and to metatarsal V. Perforated flexors (text-fig. 65. 20 a).- -Origin : from the fibrous expansion of the gastrocnemius. Insertion : into the first phalanx of digits I. to IV. These small muscles surround the tendons of the deep flexor and are inserted directly into the periosteum. Flexor longus digitorum (text-figs. 65 & 6 6 . 21).__Origin : from the hinder (flexor) surface of the internal condyle of"the femur, from the whole flexor surface of the fibula, and' from the proximal half of the fibular side of the tarsus. |