OCR Text |
Show 1895.] ANATOMY OP PIPA AMERICANA. 839 inner and under surface of the extremity of the femur; the second half has a more extensive insertion on to about the last half of the femur. The adductor longus is perfectly distinct from the foregoing, Its attachment is to the proximal part of the femur, and ends not long after the commencement of the attachment of the adductor magnus. The. adductor brevis has an attachment to the femur, which is not so long as that of the last-described muscle. . The semitendinosus has two distinct heads, which, however, lie side by side, and are quite superficial in origin. They become fused about two-thirds of the way between the origin and insertion ; a little after this they dip under the recti interni, and are inserted on to the fascia of the knee by a strong narrow tendon. The two recti interni are subequal in size. The rectus femoris group consists, as in the frog, of three muscles; but the middle muscle of the " triceps," the rectus anticus femoris, differs entirely from that of Rana. It is a thin and broad sheet of muscle, which arises entirely from tbe wide plate of bone which is formed by the transverse process of the sacral vertebra, and passes straight downwards parallel with the gluteeus to be inserted directly on to the proximal portion of the femur; it does not fuse with either of the vasti, which are both present and normal. At its insertion (see fig. 5) it is in contact with the long muscle already described as running to the lung. Pig. 5. Some of the thigh-muscles of Pipa. Ve., vastus externus ; gl., glutseus; R.f., rectus femoris; quad., quadratus ; Pso., psoas; c, biceps; lung mus., musculus pulmonum proprius; Pyr., pyriformis; obt., obturator. The biceps is a slender muscle arising just below the vastus externus; it ends by a long thin tendon upon the head of the tibia, |