Book contents
- Frontmatter
- Contents
- List of text-figures
- List of plates
- List of tables
- Introductory Note
- Foreword
- Editor's Note
- Acknowledgements
- I Introduction
- II Preservation and reconstruction of the cranium
- III The cranial vault
- IV The basis cranii externa
- V Certain critical angles and indices of the cranium
- VI The interior of the calvaria
- VII The thickness of the cranial bones
- VIII The endocranial cast of Zinjanthropus
- IX Metrical characters of the calvaria as a whole
- X The structure of the face
- XI The pneumatisation of the Zinjanthropus cranium
- XII The dental arcade and the palate
- XIII The pattern of dental attrition and occlusion, with comments on enamel hypoplasia
- XIV The size of individual teeth, absolute and relative
- XV The size of the dentition as a whole
- XVI The crown shape index of the teeth
- XVII The morphology of the teeth
- XVIII Summary of cranial and dental features of Zinjanthropus
- XIX The taxonomic status of Zinjanthropus and of the australopithecines in general
- XX The cultural and phylogenetic status of Australopithecus boisei and of the australopithecines in general
- References
- Index of persons
- Index of subjects
- Plate section
IV - The basis cranii externa
Published online by Cambridge University Press: 05 November 2011
- Frontmatter
- Contents
- List of text-figures
- List of plates
- List of tables
- Introductory Note
- Foreword
- Editor's Note
- Acknowledgements
- I Introduction
- II Preservation and reconstruction of the cranium
- III The cranial vault
- IV The basis cranii externa
- V Certain critical angles and indices of the cranium
- VI The interior of the calvaria
- VII The thickness of the cranial bones
- VIII The endocranial cast of Zinjanthropus
- IX Metrical characters of the calvaria as a whole
- X The structure of the face
- XI The pneumatisation of the Zinjanthropus cranium
- XII The dental arcade and the palate
- XIII The pattern of dental attrition and occlusion, with comments on enamel hypoplasia
- XIV The size of individual teeth, absolute and relative
- XV The size of the dentition as a whole
- XVI The crown shape index of the teeth
- XVII The morphology of the teeth
- XVIII Summary of cranial and dental features of Zinjanthropus
- XIX The taxonomic status of Zinjanthropus and of the australopithecines in general
- XX The cultural and phylogenetic status of Australopithecus boisei and of the australopithecines in general
- References
- Index of persons
- Index of subjects
- Plate section
Summary
The external surface of the basis cranii of Zinjanthropus is beautifully preserved (pls. 6 and 14). With the exception of a few parts of the left temporal bone and the apex of the right petrous pyramid, the entire basis is preserved, down to the finest anatomical detail, as far forward as the body and greater wings of the sphenoid bone. Furthermore, the parts which are missing or damaged on one side are intact on the opposite side.
The occipital bone
The planum nuchale
The character of the nuchal crest has been dealt with in the preceding chapter. Immediately below the nuchal crest, on either side of the external occipital protuberance and of the posterosuperior part of the external occipital crest, is a clear oval impression, about 27 by 16 mm., in the area between the superior and inferior nuchal lines. In modern man, the semispinalis capitis muscle is attached to a corresponding impression. Anterolateral to the last impression is another somewhat irregular impression, corresponding to the attachment of m. obliquus capitis superior. Posterolaterally, the lower lateral limb of the nuchal crest is rugged, as it flows towards the adjacent pars mastoidea and mastoid process: this part probably provided attachment to the splenius capitis muscle.
The inferior nuchal line is not very clearly defined. It runs below and in front of the impression for semispinalis capitis; then continues laterally for a short distance, turning sharply forwards opposite the impression for m. obliquus capitis superior, finally flowing over the lateral part of the exoccipital and terminating in the jugular process.
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- Olduvai Gorge , pp. 26 - 42Publisher: Cambridge University PressPrint publication year: 1967