Observations in myology : including the myology of Cryptobranch, Lepidosiren, dog-fish, Ceratodus and Pseudopus pallasii, with the nerves of Cryptobranch and Lepidosiren and the disposition of muscles in vertebrate animals / by G.M. Humphry.
- Date:
- 1872
Licence: Public Domain Mark
Credit: Observations in myology : including the myology of Cryptobranch, Lepidosiren, dog-fish, Ceratodus and Pseudopus pallasii, with the nerves of Cryptobranch and Lepidosiren and the disposition of muscles in vertebrate animals / by G.M. Humphry. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
200/224 page 172
![tional power is brought to bear upon the heel by the origin of the soleus from the tibia and by the great development of the bellies of the gastrocnemius. Thus considered, the gastrocnemius consists of the blended factors of the caudo-pedal and of the superficial layer of the pronato-flexor mass, some of which—the soleus elements—pass from the fibula, with occasionally factors from, or a connection with, the caudo-femoral. Most of these descend from the fibu- lar side of the limb. In Amphibians the fibres that do so make up the whole muscle; and there is nothing to correspond with, or rej)resent, the inner or tibial head of Birds and Mam- mals. This makes its appearance in Saurians as a thin muscular band descending from the lower edge and outer surface of the superficial plantar mass of the thigh—the part which represents the gracilis and seinitendinosus—to the tibial side of the surface of the gastrocnemius. In Birds the tibial origin is connected rather with the portion which forms the semimembranosus or the adductor; and it acquires also a connection with tibial condyle of the femur. In Mammals the relation to the muscles descending from the thigh is lost, and the connection with the femur only remains, supplemented in Man by an origin from the tibia which constitutes the inner or tibial portion of the soleus. The spreading of the gastrocnemius upon the fore part of the tibia in Birds, where it in some (Heron and Gull) is ])artially blended with the sartorius, is another illustration of the connection or con- tinuity of the flexor with the extensor, or the plantar with the doi-sal, muscles, and of the encroachment of one group upon the area of the other, of which we have seen so many instances. This ])ortion of the muscle, though separated from the remainder by the semitendinosus passing between it and the internal condyloid head, is supplied by the popliteal nerve. The blending of the sartoHus with the gastrocnemius above men- tioned is an interesting example of that continuity of the extensor and flexor muscles of the same limb, which is more remarkably exemplified, in a deeper stratum, by the continuity of the internal rectum with the flexor digitorum. Both subserve the same purpose, viz., that of assisting the action of the femoral flexors of the foot and toes during the condition of forced flexion of the knee which is so often and long maintained in Birds, and during which those flexors are much relaxed and less capable of acting upon the digits. In the fore limb the superficial stratum of the pronato-flexor](https://iiif.wellcomecollection.org/image/b21945810_0200.jp2/full/800%2C/0/default.jpg)
