Paper No. : 07 Forensic Anthropology Module : 13 Skull Suture Pattern – Individualization based on Suture Patterns Development Team Prof. Anup Kumar Kapoor Principal Investigator Department of Anthropology, University of Delhi Paper Coordinator Prof. Anup Kumar Kapoor Department of Anthropology, University of Delhi Content Writer Mr. Vineet Kumar Verma Department of Anthropology, University of Delhi Content Reviewer Prof. R.K.Pathak Department of Anthropology, Panjab University, Chandigarh 1 Forensic Anthropology Anthropology Skull suture Pattern – Individualization based on suture patterns Description of Module Subject Name Anthropology Paper Name 07 Forensic Anthropology Module Name/Title Skull suture Pattern – Individualization based on suture patterns Module Id 13 2 Forensic Anthropology Anthropology Skull suture Pattern – Individualization based on suture patterns Table of Content • An Introduction • Human Skull • Skull Bones • Exterior of the Skull • Cranial Sutures • Structure and Development of Human Skull • Skull suture development • Determining Identity through Human Skull • Age Estimation of both the Living and Deceased • Determination of Sex • Facial Superimposition • Method of Identification from the Sutural Pattern • Uniqueness of Suture • Permanence of Suture pattern • Systematic classification of Suture Pattern • Summary Learning Objectives § To determine the identity of the deceased. § To be able to define the process of examining the size, shape, and structure of a Human Skull. § To be able to classify type of Cranial Sutures. § Identifying the unknown Human remains through cranial records and cranio – facial bones. § Age estimation of both the living and the deceased. § Determining the gender of an unidentified individual. § Eliciting the ethnicity from the cranium remains. 3 Forensic Anthropology Anthropology Skull suture Pattern – Individualization based on suture patterns Introduction Forensic anthropologists work with Human skull to determine the identity of the deceased. In present times of frequent air travel, accidents and mass disasters, the identification of individual from sutural pattern will be effective for setting insurance claims, showing certainty of death of a particular individual, and performance of last rites. In medico-legal cases and mass disasters, the identification of individual is critical; individualization may refer to discrimination or perception of the individual with a group or species. The bones and teeth of the craniofacial complex, key identification tools for the forensic odontologist, effectively distinguish one person from other and one population from another, and are used to determine the race, age and sex of a person. Human Skull The skull refers to the bones which constitute the skeleton of the head and face including the mandible. The term cranium is used to describe the skull without the mandible. The cranium is divided into an upper box like part the calvarium, which contains the brain and lower anterior part which forms the facial skeleton. The fact that the primary shape of the skull is genetically determined is well demonstrated by transplantation of embryonic skeletal tissues and organ culture studies. Other characteristics of the bone seem to be self determined. Mechanical influences may not be operative at the time of establishment of the primary form of the bone. Later on muscles become active and may influence bone growth even in the pre- natal life. Cranium 8 SKULL Face 14 Number of Bones Hyoid bone 1 29 Auditory bone 6 The skull consists of 29 bones which in the adult are firmly united with each other except for the mandible. The immovable joint in the skull are called sutures. The edges of bones forming these joints are frequently serrated so that they interlock. The brain is located inside the cranial vault, a space formed by bones of the skull and skull base. Everything inside the cranial vault is 'intra-cranial' and everything outside is 'extra-cranial'. Skull Bones Bones of the skull and skull base - frontal, parietal, occipital, ethmoid,sphenoid and temporal bones - all ossify separately and gradually become united at the skull sutures. The skull has inner and outer tables of cortical bone with central cancellous bone called 'diploe'. A human skull is almost full sized at birth. However, the eight bones that make up the cranium are not yet fused together. This means that the skull can flex and deform during birth, making it easier to deliver a baby through the narrow birth canal. These individual plates of bone fuse together after about 24 months to form the adult form of skull. 4 Forensic Anthropology Anthropology Skull suture Pattern – Individualization based on suture patterns SINGLE BONE PAIRED BONE Frontal Cranium Occipital Parietal Sphenoid Temporal Ethmiod Maxillae Zygomatic Mandible Lacrimal Face Nasal Vomer Inferior nasal conchae Palatine Hyoid bone Hyoid Bone Malleus Auditory ossicles Incus Steps Exterior of the Skull The skull may be viewed in different aspects from above, below, behind, the front and the sides. Accordingly they have been named as followed: 1. Norma Verticalis (viewed from above) 2. Norma Occipitalis (viewed from behind) 3. Norma Frontalis (viewed from the front) 4. Norma Lateralis (viewed from the side) 5. Norma Basalis (viewed from the below) 5 Forensic Anthropology Anthropology Skull suture Pattern – Individualization based on suture patterns Source: https://www.flickr.com Skull may be viewed in Different Aspects Cranial Sutures The main sutures of the skull are the coronal, sagittal, lambdoid and squamosal sutures. The metopic suture (or frontal suture) is variably present in adults. ü Coronal suture - unites the frontal bone with the parietal bones. ü Sagittal suture - unites the 2 parietal bones in the midline. ü Occipito-mastoid suture- unites the temporal bones with the occipital bone. ü Lambdoid suture - unites the parietal bones with the occipital bone. ü Squamous suture - unites the squamous portion of the temporal bone with the parietal bones ü Metopic suture - (if present) unites the 2 fontal bones. ü Parietal Mastoid suture- unites the parietal bones with the temporal bone. Structure and Development of Human Skull Human skull varies in their shape and gross appearance. Their shape and structure is affected by genetic, metabolic and mechanical factors. Each skull is the result of a long functional history through innumerable successive generation. Human skull is one of the hardest structures of the body; it also possesses a certain degree of toughness and elasticity. § Cranial morphology differs dramatically in humans due to the uniquely large brains that humans have compared to body mass. It is quite distinct because it has large, rounded braincase, and flat or orthognathic face in profile. 6 Forensic Anthropology Anthropology Skull suture Pattern – Individualization based on suture patterns § “U” shaped singular construction of the human mandible. § Human crania are oriented on a vertical axis and the orbits are located in front and above the nasal aperture. These orientations also cause the position of the foramen magnum to be located inferiorly in humans. § Large bulbous vault, small face § Vault relatively smooth § Inferior Foramen Magnum § Chin present § Orbits at front, above nasal aperture § "U"• shaped mandible (no midline separation) Skull Suture Development The human Calvarium is formed primarily from five bones, the paired frontal and parietal bones and the unpaired interparietal bone. The cranial sutures allow for deformation of the skull during birth and subsequent growth of the skull. The frontal bones are separated along the midline by the metopic suture and the parietal bones are separated by the sagittal suture. The coronal suture separates the frontal and parietal bones and the lambdoid suture separates the parietal bones from the single occipital bone posteriorly. These bones are formed by intramembranous ossification and growth occurs perpendicular to the orientation of the suture. In normal development, the metopic suture undergoes fusion during the first year of life while other sutures fuse at various times during adulthood. The plates of the membranous bones making up the Calvarium of the skull are each derived from the primary ossification centre, from which bone formation spreads outward. However, the individual plates do not fuse with each other during prenatal development. As a consequence, new born babies have unclosed (open) sutures and fontanelles. These temporary discontinuities between the bones of the Calvarium aid passage of the head through the birth canal at childbirth and permit an increase in the size of the skull to match brain growth after birth. The posterior (smaller) fontanelle closes during the first year, and the anterior (larger) fontanelle closes during the second year after birth. However, some of the sutures remain open until adulthood. Determining Identity through Human Skull The bones and teeth of the craniofacial complex, key identification tools for the forensic odontologist, effectively distinguish one person from other and one population from another and are used to determine the race, age and sex of a person. Age Estimation of both the Living and Deceased Human skull; clues as to the age of skeletal remains may make an estimation of age possible. There are practical, criminal justice considerations from the age of bone. The estimation of age at death is an essential part in the reconstruction of population demographics and the individual analysis