A variation that occurs in the manubrium sterni of higher primates / by Arthur Keith.

  • Arthur Keith
Date:
[1896]
Catalogue details

Licence: Public Domain Mark

Credit: A variation that occurs in the manubrium sterni of higher primates / by Arthur Keith. 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.

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    of the pectoralis major in Gibbons. That muscle plays an important part in their peculiar method of progression by brachiation. The greatly enlarged pre-sternum offers a wider surface for the attachment of the upper part of the pectoralis major. The tendon of the sterno-mastoid also reaches on the sternum to the level of the third pair of ribs. A large pre- sternum appears to have been attained in the Orang, which has a method of locomotion very similar to that of the Gibbon, by an enlargement of the manubrium without the addition of a seg- ment of the meso-sternum. The hylobatian form of pre-sternum is to be regarded, I think, as the ordinary manubrium with the first meso-sternal Fig. 1.—Sternum of Hylobates pileatus at birth. 9 Fig. 2.—Sternum of Hyldbaies lar, 9 segment added to it. In fig. 1 is represented the sternum of a Hylobates pileatus at birth. It will be noticed that four centres have appeared, and that the fibrous septum which lies, in the human sternum, opposite the insertion of the second costal cartilages, lies, in this one, opposite the third pair. The shifting of the fibrous septum from the level of the second to the level of
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