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.
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![The exte'Tisor digitoriim hrevis or profundus is a broad thin muscle arising from the proximal row of carpal bones, and join- ing the under surface of the extensor digitorum suhlimis just above its division. It is connected with the preceding by a slip from the lower end of the ulna, which passes with it to the under surface of the ulnar part of the extensor digitorum suhlimis. Interossei are directed between the metacarpals descending rather lower on the ulnar than on the radial sides of the several bones. The similarity in the disposition of the muscles in the middle and distal segments of the fore and hind limb is very closely in accordance with the similarity in the general structure and functions of the limbs. In each they constitute a ‘jironato-flexor’ mass u|)on the palmar or plantar aspect, and a ‘supinato-extensor’ mass u])on the doi*sal aspect; and the segmentation of these masses is much alike in each. Especially in this so in the case of the supinato-extexsor ma.ss, of which the division into two strata is equally distinct in each limb, and the superficial stratum arising from the condyle of the femur or Immerus on the ‘tibial’ or ‘radial’ side, is in three parts, of which the middle passes to the digits, while the laterals are attached to the bones of the leg and forearm, and run on to the tarsus and carpus. The deej) stratum in each limb is com})osed of a supinator of the foot or hand continuous with a short extensor of the digits. In the PRONATO-PLEXOU MASS there is rather more difference in the two limbs, which is referable chiefly to the fact that segmentation is somewhat more advanced in the fore limb. In it the superficial stratum is moi’e sej>arate from the deep, though the two ai e still blended above and below; and the superficial stratum presents the three sectors—‘radial,’ ‘ulnar’ and ‘intermediate’—which is not the case in the hind limb, where the muscular force is concentrated chiefly upon the flexion of the distal parts, and is less expended on the pronation of the tibia. This stratum moreover in the hind limb receives an accession from the tail and from the pelvis. With that exception the origin in the two limbs is alike—from the fibular con- dyle of the femur, and the fibula in the one, and from the ulnar condyle of the humerus, and the ulna in the other. The deep strata in the two correspond with an exactness which is scai-cely modified by the difference in the number of the digits, each consisting, after the pattern of the dorsal antagonistic stratum, of a pronator of the foot or hand continuous with a deep flexor of the digits. There is, however, this difference between the antagonistic deep strata, viz. that a distinct vertical band or strip is in both limbs segmented from the whole length of the pronator portion, and joined more or less completely to the short flexors constituting that which I have called the deep flexor of the digits; whereas, in the dorsal aspect, the short or deep extensor is connected only with the lower edge of the supinator.](https://iiif.wellcomecollection.org/image/b21945810_0054.jp2/full/800%2C/0/default.jpg)
