On a group of varieties of the muscles of the human neck, shoulder, and chest : with their transitional forms and homologies in the Mammalia / by John Wood ; communicated by Dr. Sharpey.

  • Wood, John, 1825-1891.
Date:
[1869]
Catalogue details

Licence: Public Domain Mark

Credit: On a group of varieties of the muscles of the human neck, shoulder, and chest : with their transitional forms and homologies in the Mammalia / by John Wood ; communicated by Dr. Sharpey. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    10/40 (page 92)
    In connexion with this abnormality I would also place, as a lateral displacement, the variety recorded by R. Wagner as an irregularity of the trapezius, viz. an accessory muscle passing from near the mastoid process to the acromion process under the last- named muscle {op. cit. S. 337). Comparative Anatomy.—If we now turn to the homologies of the foregoing muscular varieties in the Mammalia, we shall find a correlation between these several developments sufficiently striking and suggestive. It was asserted by Meckel, against the opinion of Cuvier (Anat. Comp. vol. vi. p. 236), that in the lower mammalia the cervical portion of the serratus magnus was the most usual homological representative of the lower divisions of the levator anguli scapulae of Man and the higher Quadrumana; extending usually as high only as the transverse process of the third cervical vertebra, it becomes, in most of these animals, continuous with the upper border of the thoracic serratus, at the last cervical transverse process. In the Badger and Weasel among the Carnivora, the Rabbit and Surmulot among the Rodents, and in the Bonnet-Monkey of the lower Quadrumana, I have found an areolar separation of the cervical from the thoracic part more decided than that between the other digitations, a division which becomes in the higher Quadrumana still more evident. Occipito-scapular Muscle.—In 1775 Dr. James Douglass described in the Dog, under the name of the “ levator scapulae minor vel posterior,” a muscle separate from but in the same layer as the rhomboids, arising from the occiput near its crest, superficial to the splenius, and inserted in connexion with and above the rhomboideus minor into the upper angle of the vertebral border of the scapula. Under the name of the “ levator scapulae major vel anterior,” he also described, in the same animal, a ribbon-shaped muscle, arising from the first cervical transverse process, and inserted into the scapular spine near its outer end. In these two muscles we have evidently the homologues of the opposite extremes of the human varieties before described, and represented by the fully formed occipito-scapular and levator claviculce. The homologue of the former was described by J. F. Meckel, under the name of the rhomboide anterieur, as a separate muscle, reaching from the angle of the scapula to the occiput, in the Magot and Lemurs, and forming one sheet with the rhomboids in the Coati. In the Insectivora he describes it in the Mole and Hedgehog as a separate muscle, and in the Armadillo as joined with the rhomboids. In the Carnivora he describes it in the Marten, Potto, Bear, Hyaena, Badger, Dog, and Cat, usually united to the other rhomboids and reaching as far as the occiput. In the Rodents he describes it in the Beaver, Porcupine, and Marmot, partially separated from the other rhomboids in the first, but united to them in the two latter; and he also describes it in the latter condition in the Didelphis marsupialis (Anat. Comp, vol. v.). In Cuvier, Laurillard, and Mercier’s magnificent ‘ Receuil de Planches de Myologie’ (Anat. Comparee, Paris, 1855), this muscle is figured under the name of the “ rhomboide de la tete ” as large and separate from the other rhomboids in Callitlirix, Magot, Papio Mormon, Coati, Sajou, and Marmoset. In the Lion it is represented as continuous with the other rhomboids; but it constitutes a separate muscle in the Panther,