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

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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$mass never acquires an origin from the radial condyle, such as would correspond with the tibial head of the gastrocnemius which we find in the hind limb of Birds and Mammals. The covering fascia, strengthened by prolongations from the pectoral and biceps, perhaps also from the latissimus dorsi, and some- times strengthened by muscular fibres derived from the ulnar condyle which constitute the pahnaris longus, is the representa- tive of the caudo-pedal. The most distinct example of a pro- longation of the ventral muscle upon the palmar aspect of the fore limb—the most distinct serial correspondent, in short, of the caudo-pedal—is, however, as stated p. 131, furnished by the costo-alaris of Birds \ Forasmuch as the carpus retains in all animals the flattened form, there is not here, as in the hind limb, a tendency to con- centration upon a heel-bone thrown up in the middle, or an interruption of the several muscles by such a process. The components of this stratum are, therefore, more equally disposed upon the surface as they descend, than those of the hind limb; and they present a more distinct division into ulnar, radial and intermediate sectors. Of these the ulnar sector {flexor carpi ulnaris^), inserted into the cuneiform (with the pisiform) bone which is the homologue of the os calcis, is the chief representa- tive of the gastrocnemius and soleus. In the intermediate sector, the palmaris I expanding into the palmar fascia, where it blends with fibres of the flexor carpi idnaris, represents the superficial part of the gastrocnemius; and i]\Q flexor sublimis digitorum^ represents the plantaris and the flexor brevis ^ I have said that the costo-alaris is to some extent the serial representative of the caudo-pedal, and that the palmaris 1. is also a like representative of the same muscle. An interesting exemplification of the relation of these parts is afforded in Phoca by the palmaris 1. which, instead of arising as usual from the condyle of the humerus, passes upon the olecranon and blends with a portion of the triceps commg from the angle of the scapula, which again is in close con- nection with the latissimus dorsi; and it spreads like the costo-alaris upon the ulnar side of the carpus and hand. ' The similar exemplification in Mania afforded by the direct continuity of the latissimus dorsi with the palmar fascia and the flexor subl. dig. has already been pointed out. 2 The fl. c. u. is not subject to much variety. It sometimes (Unau and Cyclothurus) spreads across the widst superficially, meethig an expansion from the supinator longus; or (Phoca) it spreads beneath the palmaris 1.; or it blends with the latter muscle or with the annular ligament. In the Proboscis Monkey it meets the sup. 1.; and the expansion formed by them lies superficial to, and can be dissected off from, the fascia of the forearm. ® The fl. d. s. is partially interrupted at the carpus in Pteropus; and the palmaris 1. in Ai. In Seine the fl. d. s. is tendinous at the wrist and ex'pands$