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.

  • John Wood
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.

    8/40 page 90
    the superior curved line of the occipital bone, as well as by a more or less marked areolar interval between the two. The fibres of the latter muscle are directed from the clavicle upwards and forwards in such a manner as to become, in the upper part of the neck, entirely covered by those of the sterno-mastoid, which form here the entire pos- terior border of the compound human sterno-cleido-mastoid muscle, to the exclusion of those of the cleido-mastoid, which pass more deeply and are directed more forwards to the mastoid process. We have found the cleido-occipital muscle more or less developed in 37 subjects out of 102, viz. in 27 out of 68 males, and in 10 out of 34 females. In 34 it was found on both sides, and in 3 on one side only. In two instances in which it was found on one side only, there existed on the opposite side a levator claviculce muscle, showing a sort of correlation between the two formations. In two instances the muscle was double, or divided into two distinct portions. In two more male subjects the formation was so peculiar as to merit a more detailed description ; one of them was the subject of fig. 29, Plate XI. Besides the ordinary clavicular attachment (<?), which was connected with the bone near to that of the trapezius (T), so as almost entirely to cover the posterior triangle, there arose from the sternal end of the clavicle, external to and partially separate from the sternal origin of the sterno-mastoid, a strong flattish tendon giving origin to a considerable bundle of parallel muscular fibres (c'). These crossing upward and back- ward, superficial to the origin of the cleido-mastoid proper (b), joined, about the middle of the neck, the fibres from the ordinary origin (c), and were inserted with and anterior to them into the superior curved line of the occipital bone. The appearance of a com- pletely double sterno-cleido-mastoid was thus given to the subject, bearing a striking resemblance to the formation of the homologous muscles in the striped Hyaena, Polecat, Genette, Coati, and Marmot, as figured in Cuvier and Laurillard’s plates of these animals. The muscular variety which I have distinguished by the name of cleido-occipital has been observed and described by various writers as an occasional variety of the sterno- cleido-mastoid or trapezius muscles. It is mentioned by Sommerring (De Corp. Hum. Fabric, p. 112), and was found by Kelch coexistent with a double sterno-cleido-mastoid, the whole possibly having been a formation similar to that last described (Beitrage, xxi. p. 31). Meckel describes it, both in the human subject and in animals. In the latter he states that it sometimes joins, below, the anterior fibres of the deltoid {cephalo-humeral); and in his description of Ateles and Magot, and some other animals, he seems to have looked upon it as a variety of the acromio-traclielien (levator claviculce), and through this arrangement he appears, moreover, to have connected the latter with the trapezius rather than with the levator anguli scapulae, as indicated by Cuvier (Meckel, De Du- plicitate Monstrosa, pp. 40, 41, and Muskellehre, p. 475). Theile describes an oblique slip of muscle, three lines wide and one thick, attached to the superior curved line of the occipital bone, partly under the trapezius, and spreading
    digitised image 1
    digitised image 2
    digitised image 3