Brief resume of the intended work:
6.1 Need for the study:
The human skull has been studied both metrically and non- metrically
previously. Cranial index and other cranial indices are useful when the data obtained from the study can be used to investigate the variations within species, which include sexual dimorphism, geographical and ethnic differences in further studies.
6.2 INTRODUCTION AND LITERATURE REVIEW :
Craniometry is the scientific measurement of the skull useful for anthropometry and forensic practice1. Cranial index variations between and with in population have been attributed to a complex interaction between genetic and environmental factors2 .The bone material is very important after enamel of teeth for anthropometry and forensic practice. The morphometric and non-morphometric studies of human skulls are very helpful for identification of the sex and age by anthropologist and forensic practice. Cranial dimensions and Cranial indices are considered as simplest and most efficient way to indicate facial differences3.
Craniometry generally conducted by X-ray techniques but is closely related to anatomists and anthropologists4. Craniometry can be used to analyze evalution of human species in archeology5.
According to Williams et al the skulls are divided four types based on cranial index, types are as follows
Dolicocephalic – Cranial Index less than 74.9mm
Mesocephalic – Cranial Index between 75 to 79.9mm
Brachycephalic – Cranial Index between 80 to 84.9
Hyperbrachycephalic – Cranial Index 85 to 89.9
The author stated that the insignificant difference in the cranial indices of the male and female skulls confirms the less sexual dimorphism in humans as compared to other primates6.
The cranial anthropometry can be helpful in the study of human growth variation in different races, for clinical diagnosis and treatment (Poswillo, 1963). Also it is essential in the study of population dynamics of specially with respect to quantitative variables (Odoquma et al., 2010)6
According to Sharma RN the cranial index in living is two units higher than cranial index which measured on dried human skulls, In Mongoloid race dolicocephaly is rare while brachycephaly is rare in Negroid race. Human knowledge of paleontology and available data suggest that early man was generally dolicocephalic. Brachycephaly developed later as a result of repeated mutation and various other factors7
Cranial measurements and indices offer the simplest and fairly accurate way of judging the similarities and dissimilarities when comparing skulls. Craniometric methods have a special usefulness in forensic practice while making identification in medicolegal cases8 . Cranial indices can be playing a part in reconstruction of skeletal remains. Craniometry has further application in clinical specialities such as plastic surgeries and oral surgery with craniofacial deformities9
6.3 Objectives of the study:
Measure and calculate :
Cranial length-height index
Cranial breadth – height index
Orbital index – Right and left
To classify the skull under different subtypes .
To compare the findings with those available in the literature .
To obtain data which can be used to investigate the variations within species, which include temporal changes, sexual dimorphism, geographical and ethnic differences in further studies
7. Materials and methods:
7.1 Source of data :
The present study will constitute 100 dried adult skulls belonging to both sexes available in the department of anatomy RRMC&H Bangalore.
Digital vernier calipers
Methods: Measurements will be made on all skulls by mounting the skull and fixing it in anatomical position . The measurements which could be taken accurately with the skull fixed on the stand will be recorded , whereas the rest of the measurements will be made on the skull by demounting it from the stand .
A)Cranial measurements :
Maximum cranial length = One point on the glabella(is the space between the eyebrows and above the nose) and another point at the opisthocranion(the posteriormost point in the midsagittal plane of the occiput) is taken and the maximum cranial length will be measured .
Maximum cranial breadth = This is measured at right angles to the mid-sagittal plane where ever maximum breadth is found , above the level of the supramastoid crests or posterior roots of the zygomatic arches and the regions below.
Basion – bregmatic breadth = The greatest breadth between the two zygomatic arches will be measured .
Maximum bizygomatic breadth = The greatest breadth between the two zygomatic arches will be measured .
Upper cranial facial height =length between the nasion( the intersection of the frontal bone and two nasal bones) and prosthion ( the point on the maxillary alveolar process that projects most anteriorly in the midline.)points will be measured.
Basion Prosthion line = Distance between basion( the midpoint on the anterior margin of the foramen magnum on the occipital bone.) and prosthion points will be measured .
Nasal height = From nasion to the mean of the lowest points on the lower border of the nasal aperture ( the sub nasale) on each side of the nasal spine will be measured.
Nasal breadth = This is the maximum distance between the lateral margins of the nasal aperture perpendicular to the mid-sagittal plane.
Orbital Breadth = Owing to the variability in the confirmation and orientation of the orbits these are conventionally treated as rectangles . The horizontal axis being determined by an imaginary line running from to the middle of the lateral orbital border (ectoconchion) . Right and left orbits are recorded separately .
Orbital height = The maximum height is measured from the upper to the lower orbital borders perpendicular to the horizontal axis of the orbit( orbits being treated as rectangles) Both left and right will be measured..
Palatal length = Distance between the posterior nasal spine and the prosthion . This constitutes palatal length.
Palatal breadth = Maximum distance between two points opposite the molars is measured using sliding compass. This is taken as the palatal breadth .
Basion nasion length = One point at the basion and the other at the nasion is taken . The distance is measured .
B) Cranial indices :
a.Cranial index = Maximum cranial breadth x 100/ Maximum CL
b.Lenght-Height index=Basion-bregma height x 100/Maximum CL
c.Cranial Breadth-Height index=Basion-bregma height x100/
d.Orbital index=Max.orbital breadth x100/Max. orbital length
e.Nasal index=Max. Nasal breadth x100/Max. Nasion-nasospinal
f.Palatal index= Max. palatal breadth x100/Max. palatal length
[CL= Cranial length , CB= Cranial breadth]
7.3 Statistical analysis:
Statistical analysis will be carried out by distribution analysis ,Critical ratio and correlation between the indices will be calculated to find out it’s significance between the compared indices .
7.4 Inclusion criteria :
Complete adult crania
Exclusion criteria :
7.5 Does the study require any investigations or interventions to be conducted on patients or other humans or animals?
7.6 Has the ethical clearance been obtained from your institution in case of 7.3?
8. List of references:
1. El-Feghi, I, M.A. Sid-Ahmad, M. Ahmadi. .Automatic localization of craniofacial landmarks for assisted cephalometry. Pattern Recognition. 2004;37: 609-621
2. Kasai K.L.C, T. Richar, Brown T. Comparative study of craniofacial morphology in Japanese and Australian aboriginal population. Hum. Biol. 1993;65: 821-832.
3. Chaturvedi RP and Harneja NK. A cephalometric study of human skulls. Journal of Anatomical Society of India. 1963;12:93-96.
4. Reinmann F, Gurgan M, Koc L, Varan G. Determination of length, width and height of the human skull by critical use of roentgenologic craniometry methods. Roentgenblatter. 1987;40(11): 36-38.
5. Douglas SJ. Cranial capacity and endocranial cast. Traumatology Journal. 1990;4(1): 56-65.
6.William PL, Bannester LH, Berry MM, Collins P, Dyson M, Dussek JE and Ferguson MWJ (1995). Gray’s Anatomy. Soames, R.W: 38th Edn, London: Churchill Livingstone pp 612.
7. Sharma R. N. Criteria of racial classification. In: Physical Anthropology. Surjeet publication .2005;226p.
8. Jaysingh P, Arora A K, Gupta C D, Dua S, Pandey D.N. Craniometric study of skulls of Uttar Pradesh. J. Anat. Soc. India 1979, 28(3):127-131
9. Williams P. L. and Dyson M. Skeletal system. In: Gray’s Anatomy, 39th ed. Elsevier Churchl 2004; 487-489.
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