Facial Reconstruction - Book

What is Forensic Medicine? Forensic medicine is also called as Legal medicine or Medical jurisprudence is a branch of medicine, which deals with the interaction of medical science with the law. The name “Forensic” comes from “forum”, the Roman market place where lawyers did their business.

Forensic

medicine provides one of the most fascinating of all the many branches of medicine.

All branches of medicine, including Anatomy, Pathology,

Dentistry, Physiology, Biochemistry, Therapeutics, Obstetrics, Paediatrics and many others, can be called into play to assist in medico-legal problems. Every speciality in medicine can have forensic aspects at sometime or another.

What is Death? Death is not merely the absence of life, as in a stone, but the cessation of life in a previously viable organism. However, there can be no single definition of death, as death is a process and not an event. Types of death can be broadly classified in to two types: 1. Somatic death ---- means that “the person no longer functions as a

unit of society, because he is irreversibly unconscious and therefore cannot communicate with the environment and is unaware of his own

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or the world’s existence”. The word ‘irreversible’ is vital in this definition, as otherwise the criteria of somatic death would be fulfilled when asleep, under anaesthesia or in a temporary coma.

2. Cellular

death ---- means “the cessation of respiration and

metabolism of the body tissues, which is soon followed by autolysis and decay”. This is indisputably true death when it affects the whole body, but almost never occurs simultaneously, except perhaps in a nuclear explosion; even when a person is blown up by a high explosive bomb, the cells of the fragments of skin, bone, etc., live for atleast some minutes or even hours, which is not so in the case of a nuclear explosion.

Causes of Death The causes of the death which are forensically related can be broadly grouped in to three categories: 1.

Suicidal ---- also called as self-induced death.

Ex. Railway track suicide, Gun shot suicide, CO inhalation, etc.,

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2.

Homicidal ---- this is the type of death caused by others.

Ex. Sexual assaults, Road traffic accidents, Tortures, etc., 3.

Natural ---- this is the type of death, which occurs due to natural ageing or due to certain pathologies within the body.

Why are we concerned about death? Almost all doctors, whatever their speciality, come in to contact with death at sometime or other in their professional work.

The legal and illegal

aspects of this inevitable process form an important part of Forensic medicine.

Commonly used terminologies. Postmortem – after death Antemortem – before death Perimortem – near or around the time of death.

The early changes after death.

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Within a short time, a whole spectrum of changes begins to occur, at first on a cellular level, then becoming obvious to the naked eye. The doctor must be aware of the general nature of these changes, both to avoid mistaking them for signs of an unnatural death, and in the determination of how long the person may have been dead. The changes that take early after the death are: •

Rigor mortis --- Most dead bodies become stiff at a variable time after death, this later passing off to allow secondary flaccidity. It is due to combination of actin and myosin within skeletal, cardiac and involuntary fibres irreversibly into a gel, causing the muscle to become stiff. Rigor mortis tends to appear more quickly in persons who die during or soon after physical exertion, exhaustion or electrocution. In the old and in infants, rigor may be absent or hardly detectable. It is usually detectable in the area of smaller muscles such as those around eye and mouth, the jaw muscles and the fingers. The process begins at death, usually becomes manifest within two to four hours and advances until approximately twelve hours, when it is generally complete.

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Cadaveric rigidity --- is a relatively rare phenomenon, where rigor mortis sets in immediately after death. •

Livor mortis --- It appears as a purple discolouration of the skin on the dependent parts of the dead body. It is caused by settling of the blood into the capillaries of the skin as they become dilated after circulation ceases. Since it depends on gravity, it will be absent in areas of the body where the weight produces pressure and occludes the capillaries.

Livor mortis formation begins immediately after

death, but it may not be perceptible for as much as two hours. It is usually well developed within four hours and reaches a maximum between eight and twelve hours. During this period, if the body is turned over, the lividity that was originally dependent will shift to the newly dependent areas. However, after eight to twelve hours lividity becomes fixed and will remain where it originally formed.

•

Algor mortis --- It is the term for the normal cooling of the body after death.

Rigor mortis, livor mortis and algor mortis are processes that are independent of one another, but they generally occur simultaneously.

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Forensic Art Forensic art is “any art that is of forensic nature; that is, art used in conjunction with legal procedures”. A working definition of forensic art is “any art that aids in the identification, apprehension, or conviction of criminal offenders, or that aids in the location of victims or identification of unknown deceased persons”. Forensic art is often multimedia in nature; its primary purpose is to present visual information.

Is it an Art or Science? Forensic art is a blend of art and science. This art / science relationship occurs because forensic art can present scientific information or use scientific principles in a visual format rather than a verbal one. Practical examples of the art / science blend may include: • Knowledge of cognitive psychology, behavioural science interview techniques and facial anatomy used during composite imagery sessions.

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• Application of craniofacial growth data in the preparation of child age progression.

• Pathology, fingerprint, trace evidence, or other scientific findings incorporated into illustrations for court presentations.

• Taphonomic, anthropological, or odontological data used by the artist when creating postmortem drawings or two-dimensional and threedimensional facial reconstructions from skull.

Facial Reconstruction

Facial Reconstruction, the most commonly used term to designate the procedure of projecting a soft tissue based on skull architecture. Facial Reconstruction from the Skull is the most accurate terminology for 2-D Facial Reconstruction, whereas, Facial Reconstruction on the Skull is the most accurate

phrase for 3-D Facial Reconstruction.

Regarding

terminology, the term reconstruction is here considered as preferable to 7

other synonyms such as reproduction and restoration.

The term

reproduction implies a perfect replication, which is never the case, and the term restoration more aptly applies to soft tissue repairs on damaged but still intact remains. Facial approximation is perhaps a better description of the procedure but this term is not in general use. The three major types of Facial Reconstruction are: •

2-D Facial Reconstruction --- Type of reconstruction in which tissue depth markers are used and the facial approximation is done using pencil drawings.

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3-D Facial Reconstruction --- Type of reconstruction in which the tissue depth markers are placed on the skull and then the facial reconstruction is done using plasticine (clay) directly on the skull.

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Computer Aided Facial Reconstruction --- The skull is scanned or photographed and a resin cast of the skull is obtained and on which the reconstruction process is done.

This seminar presentation will cover the procedural steps of 3-D Facial Reconstruction and Computer Aided Facial Reconstruction.

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3-D Facial Reconstruction Before attempting Facial Reconstruction, as much information as possible should be gathered concerning a particular case. Various scientific specialists may need to be consulted, particularly a skilled physical or forensic anthropologist.

Only through anthropological evaluation to

determine age, sex and ancestry the artist can select the appropriate tissue depth data as preparation for rebuilding a face on the skull. 3-D Facial Reconstruction can be done in three ways: •

Anatomical method --- In this method, muscles are defined individually to flesh out the face, and tissue depth data are not utilized.

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Tissue depth method --- Involves use of data gained in anthropological studies as a guide for building up to the facial surfaces. All tissue depth data are used.

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Combination method --- The most advantageous method for use in law enforcement is probably a combination of both the anatomical approach and the tissue depth approach. Few tissue depth data are utilized.

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In this seminar presentation, Combination method will be dealt with in detail.

Combination Method Armamentarium Required Tools • Sculpture tools: flat wooden spatula, wire tools and pointed wooden stick • Boley-style gauge (in millimeters) • Metal scale • Plastic brayer or roller • X-acto knife and blades Materials • Oil-based modelling clay (Plasticine), 10 to 12 lbs • Duco© cement (or other adhesive soluble in acetone) • Cotton balls • Cotton swabs • Vinyl machine eraser strips • #40 grade sand paper 10

• Aluminium “Gutter Guard” or flexible mesh

Facial Reconstruction is a two-phase process. The steps of the phases for 3-D Facial Reconstruction are: Technical phase  Receipt of skull & gathering case information  Skull protection & preservation  Gluing the mandible to the cranium  Placement of skull on an adjustable stand  Orientation into the Frankfort Horizontal Plane  Cutting and placement of tissue depth markers  Setting the prosthetic eyes  Connecting the tissue depth markers to establish facial contours

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Artistic phase  Development of the mouth  Development of the eyes  Development of the nose  Development of the cheeks  Development of the ears  Development of the neck  Texturing & surface details  Hair / Wig  Photographing the sculpture A skull may tell of age, sex, race, and thus in part contribute to cranial identification, but it may do more; it may provide a further individualization, for it may give clues to cephalic identification. This is to say that the dead skull is, in a sense, the matrix of the living head; it’s the bony core of the fleshy head and face in life. Upon the cranial framework we may build bit by bit, until details of physiognomy take shape, and a reasonably acceptable facsimile of a living human head emerges.

Step 1: Receipt of skull & gathering case information

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• A case file should be created and maintained for every skull / facial reconstruction case. • Written documentation of the care, custody, and control of a skull or any evidence should be done. • Specify whether you receive a complete skull or the specific portions for incomplete material. • Inventory of the teeth is particularly significant. Even if you are not familiar with dental charting, you can at least count and note the number of the teeth received. • It is important that you get the signature of the person from whom you received the skull, along with the date. • Details like clothing, jewellery, hair specimens, eyeglasses, etc., can be obtained; as it will be difficult to identify Charlie Chaplin in a casual dress. • Above all, the skull should be treated with respect. It is what remains of a living, breathing human life and should not be an object for jokes and pranks.

Step 2: Skull protection and preservation • Skull should always be handled with care. 13

• Never pick up a skull in the facial area by placing fingers in to the orbits of the eyes or in the nasal aperture, its not a bowling ball. • Place the thumb in to foramen magnum and the palm supporting the base of the skull.

• Loose or fallen teeth should be replaced with professional help. • To protect inner structures of nasal aperture from fractures, place a small cotton ball inside and cover it with some clay. • Orbital bones can be protected by placing cotton roll in to them and cover with strips of masking tape, this also facilitates easy removal of clay after the reconstruction procedures.

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• Fractures or bullet wounds may need to be taped with masking tape to avoid being filled with clay. • Prevent the skull from rolling off a table by securing it on a cork ring.

Step 3: Gluing the mandible to the cranium • Once the teeth are secured in the skull, the artist should carefully evaluate the dentition for potentially useful information before gluing the mandible to the cranium.

• Assessment of the teeth and bite can provide information not only about the appearance of the mouth area, but in some cases also hints about the socioeconomic status of the individual during life.

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• A clean, open socket usually indicates postmortem loss of a tooth, while a socket filled in with bone may mean that a tooth has been missing for a period of years. • In life, the condyle of the ramus is covered by cartilage and there is an articular disc in the temporomandibular joint; this spacing is simulated with the help of the clay, cotton, gauze or other materials. Bone-tobone gluing should be avoided. • Spacing between the teeth of the two jaws ( Freeway space ) should be maintained by placing a toothpick on the posterior teeth region and glued. • Secure the mandible further by adding glue on the occlusal plane.

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• In a completely edentulous skull, the mandible can be positioned using a pencil placed through the mandibular notch, behind the pterygoid and through the opposite mandibular notch.

• If the skull has complete dentures, the dentures can be placed on the prepared bony area. In life, dentures don’t sit on the bone, so some

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clay should be used to simulate the missing gingival tissue and then dentures over it.

Step 4: Placement of skull on an adjustable stand • Mount the skull on the adjustable skull stand once it is assembled. • Insert the spring opened wings of the toggle bolt against the inside of the skull through the foramen magnum and tighten the wing nuts securely.

Step 5: Orientation into the Frankfort Horizontal Plane • The Frankfort horizontal plane is an anthropological standard position that closely approximates the natural position of the head in life. • Orbitale, the lowest point on the lower margin of the orbit, is horizontally aligned with porion, the most lateral point on the root of the external auditory meatus.

Step 6: Cutting & placement of Tissue Depth Markers • Since every individual skull presents its own challenges, gluing of the Tissue Depth Markers has to be somewhat tailored to each particular skull. 18

• We wish to emphasize the need for accurate cutting and placement of the tissue depth markers. • Cut vinyl eraser material to the depths for the markers and number them. • Take care not to cut markers at an angle, but rather straight up and down.

Landmarks for location of tissue depth markers •

1. Supraglabella – Placed above glabella

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2. Glabella – The most prominent point between the supraorbital ridges in the midsagittal plane

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3. Nasion – The midpoint of the suture between the frontal and two nasal bones

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4. End of Nasals (Nasals) – The anterior tip or the farthest point out on the nasal bones

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5. Mid-philtrum – The midline of the maxilla, placed as high as possible before the curvature of the anterior nasal spine begins

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6.

Upper lip margin (Supradentale) – Centered between the

maxillary central incisors at the level of CEJ •

7.

Lower lip margin (Infradentale) – Centered between the

mandibular central incisors at the level of the CEJ •

8.

Chin-lip fold (Supramentale) – The deepest midline point of

indentation on the mandible between the teeth and the chin protrusion •

9. Mental eminence (Pogonion) – the most anterior or projecting point on the midline on the chin

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10. Beneath chin (Menton) – The lowest point on the mandible

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11. Frontal eminence – Place on the projections at both sides of the forehead

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12. Supraorbital – Above the orbit, centered on the upper most margin or border

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13. Suborbital – Below the orbit, centered on the lower most margin or border

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14. Inferior malar – The lower portion of the maxilla

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15. Lateral orbit – Drop a line from the outer margin of the orbit and place the marker about 10mm below the orbit

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16. Zygomatic arch, midway – Halfway along the zygomatic arch. It is generally the most projecting point on the arch when viewed from above

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17.

Supraglenoid – Above and slightly forward of the external

auditory meatus at the deepest point •

18. Gonion – The most lateral point on the mandibular angle

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19. Supra M2 – Above the second maxillary molar; if the second molar is missing, the marker should be placed in the approximate area where it would have been

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20. Occlusal line – On the mandible in alignment with the line where the teeth occlude

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21. Sub M2 – Below the second mandibular molar; if the second molar is missing, the marker should be placed in the approximate area where it would have been

Step 7: Setting the prosthetic eye • Human eye is approximately 25mm in diameter. • Use of plastic prosthetic eye caps is preferred for their realistic appearance and ease of modelling the eyelids as and then. • Sometimes eyes too can be carved out of clay. 21

• Choice of colour of prosthetic eye to be used should be based on the information provided by the anthropologist and may also require some guess work. Frontal View Placement  When viewed from the front, the prosthetic eye should be basically be centered within the orbit, North and South, East and West.  As Krogman states: “Rotation of eyeball to bony orbit …… the apex of the cornea when viewed from norma frontalis, is at the juncture of two lines, one drawn from the medial edge of the orbit (maxillofrontale)

to

the

lateral

margin

of

the

orbit

(ectoconchion); and the orbit line bisecting the orbit between the superior and inferior margins”.

Lateral View Placement

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 Referring to the placement of the eye in the lateral view, Krogman further states: “The outer point of the cornea is approximately tangent to a centrally located line drawn from the superior and inferior margins of the orbit”. • After the prosthetic eye is correctly positioned on a small stem of clay, small amounts of clay should be modelled into help secure it in place.

Step 8: Connecting tissue depth markers to establish facial contour • To reiterate, gluing the tissue depth markers in place and then connecting them with clay will provide the general shape of the face, based on the shape of the skull. • By carefully maintaining the accuracy of the thickness of each piece of clay applied, these strips function as large-scale tissue depth markers. • It is important to note that the tissue at the lateral or outside of the eye is only about 5mm thick; the clay should therefore taper in at the corner of the eye, clinging close to the bone. 23

• “Back triangle” area formed by tissue depth markers # 15, 16, 17 is created with larger pieces of clay. As this triangular area of clay is added, the back portion of the Masseter muscle and a portion of the parotid gland are being simulated.

• The next area covered is the chin. Place a long strip of clay rolled to the depth of the marker #10 all along the lower edge of the mandible. This is called as “Jaw strip”.

• “Front triangle” area bounded by tissue depth markers #15, 13 and at about halfway between #9 and 18. This area can be filled with larger pieces of clay and smoothed. 24

• The head is filled with larger strips of clay.

Step 9: Development of the mouth • To build the mouth barrel for a closed mouth, you need three dimensions: the depth of the lips, the vertical thickness of the vermilion, and the width of the mouth side to side. o The depth of #7 tissue depth marker determines the depth of the mouth. o Measuring the combined height of the enamel of the upper and lower teeth, i.e., upper CEJ to lower CEJ derives the vertical thickness for the mouth. o The width of the mouth is generally determined by measuring the front six teeth mesio-distally. • A strip of clay to the required depth of the mouth is taken and placed to fit the width of the mouth. • A thin line of clay is removed on the strip using a wire tool, so as to depict the upper and lower lips. Lower lip is always slightly bigger than that of the upper lip. • Spread the lips from the partition line with a flat wooden tool, pushing the upper lip upward and the lower lip downward. 25

• The index finger is used to scoop out the philtrum on the upper lip. • Further shaping is done by placing three small dabs of clay on the upper lip and two small dabs on the lower lip. This helps in giving the lips a more naturalistic shaping.

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• You may also wish to add light lines in the clay lips to represent the striations within the lips.

Step 10: Development of the eyes • As with the refinement of the mouth, the sculptural development of the eye should be done keeping in mind the race, age and expression of the individual being reconstructed.

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• Expression may become a factor if you prepare a smiling version of the reconstruction. Has the mouth been developed in an open or closed manner? This will affect the degree to which the eyes squint as well as cheek formation. • To begin forming the eyelids, roll a section of clay to a depth of about 4mm. From this clay, cut four small strips for the eyelids that are 7mm by about 40mm. The ends of each of these eyelid strips must be angled to form four small trapezoids.

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• The lower eyelid strips are applied first and may require several adjustments to correct the length. • Keep in mind that the eyelids must fit inside the bony orbits. • The eyelids should hug the eyeball as you place them on the lateral side and come around just to the bottom of the iris. • As they wrap around toward the medial canthus or inner corner of the eye, they deviate away from the eyeball slightly, creating an S-curve. Thus, the medial canthus is naturally closer to the frontal plane than the lateral canthus or outer corner. •

After the lower lids are in place, a small ball of clay is placed at the medial canthus to represent both the caruncle lacrimalis, the pink tissue at the inner corners of the eyes.

• The upper eyelid strips, also started from small trapezoids, should be slightly longer and more arched than the lower lids. • The upper eyelids should hug the eyeball as we place them on the lateral side and then come around to the iris. • Then, as they wrap around toward the medial canthus or inner corner of the eye, they deviate away from the eyeball slightly, as with the lower lids, coming over the caruncle.

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• At the outer sides of the upper eyes, there should be fullness to represent the forms of the lacrimal gland. • To fill in the remaining areas around the eyes, you must consider the underlying structures as you connect these areas to the eyelids. The nasal bones should be covered by clay to a thickness of the #4 depth marker, because the flesh is close to the bones in that area. • As a rule, the medial canthus of the eye is slightly lower than the lateral canthus to facilitate the tear drainage process. • Occasionally, it may appear that a person has a lower lateral canthus, but closer examination usually indicates that, in reality, it is an area of sagging skin, not truly the eye corner. • The eyebrows may be indicated at this stage, but you will probably choose to detail them more in the finishing stages.

Step 11: Development of the nose • The nose will be based specifically on the individual skull that you are reconstructing. You will notice that it is the nose that is usually the most accurate feature.

Certain “rules of thumb” for nose

projection given by Dr.Wilton Krogman are:

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o Frontal view – Soft tissue nasal width is based upon the bony

nasal aperture. For Caucasoids, the nasal aperture is measured at its widest point and then 10mm is added to get the total width (5mm on each side). For Negroids, the nasal aperture is measured at its widest point, and then 16mm are added to get the total width (8mm on each side). The width for Caucasoids and Negroids can be averaged for a best guess for Mongoloids. o Lateral view – It is necessary to first measure the length of the

bony nasal spine. Then, that length is multiplied by 3 and added to the depth of depth marker #5. The nose projection is from subnasale to pronasale, approximately three times the length of the nasal spine.

• Applying the skull dimensions to construct the nose:

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o Frontal view – The attachment of the nostrils is generally 4 to

5 mm lower than the bottom or sill of the nasal aperture. The appropriate nose width measurement should be applied to the base of the nose by marking the clay with the Boley gauge. This provides an indication of the total width of the nose. Then the nose is roughly shaped in clay, adhering to its width. o Lateral view – The total projection of the lateral nose must be

indicated in the clay profile. A convenient way to accomplish this is by forming a block of clay that is the length of #5, or mid-philtrum tissue marker, plus the projection calculation. The block of clay can then be placed slightly inside the nasal opening and on top of the nasal spine to form the architecture of the nose. Then the lateral nose is roughly shaped in clay, adhering to this projection.

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Step 12: Development of the cheeks • The cheeks can be made more lifelike with attention to their contours. • Consideration should be given to the race, age, sex and expression of the individual whose face you are reconstructing. • In addition, you should carefully observe the placement of the zygomatic bones, especially in the lateral view. • The cheeks should be rounded to conform to their more advancing or receding nature. • The cheeks actually come off of the bridge of the nose, proceeding to the top edge marker #13, rounding out and down toward the mouth. • The naso-labial furrow at the side of the nose is created with age by the action of the Zygomaticus muscles pulling the corner of the mouth up and back. The furrow originates at the top of the alar groove and becomes more pronounced with age as the tissue sags downward and forward from the zygomatic bone.

Step 13: Development of the ears • Ears seem to strike fear into many artists. Many opt to cover them with hair or omit them all together. You should learn to correctly sculpt an ear, since there will eventually be a case of an individual 33

with short hair and exposed ears.

Learning the basic anatomical

structures goes a long way toward demystifying the process of making ears. • In this method, the ears are first built and then applied to the sculpture. •

For a right ear, form a cylindrical piece of clay about 2 inch long and 5/8 inch in diameter. This piece is the basis for the antihelix.

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Hold the clay cylinder in your left hand, and press your right thumb into the middle of the cylinder while pushing your left hand to create a “C” or cup shape, creating the concha.

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Use a wooden tool to develop the top of the Y-shaped form of the antihelix by pressing in the triangular fossa.

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Next roll out a coil of clay about 6 inch long and ¼ inch in diameter. This coil should be added below the lower part of the Y-shaped spiraling up, out, and around the perimeter to form the helix.

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Blend this coil around the cup-shaped concha form, creating the schaphoid fossa and then merging it in completely near the bottom at the beginning of the lobe.

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Continue to shape the concha more smoothly and form the antitragus, intertragal notch and lobe.

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Make a mirror image of the ear you have just built, so that you will have a pair. The ears are ready to be attached to the sculpture adding the tragus.

• To attach the ears to the head, the neck should be developed first and then several points must be considered in order to get a naturalistic ear placement. • The external auditory meati or bony ear holes, dictate specifically where the ears must be positioned. •

Ears usually rest at a backward angle of about 15°.

Particularly

important is that the ears sit behind the angle of the jaw.

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• The ears should attach rather closely to the head at the anterior or front portion and tip out or away further from the head at the back portion. The ears should not appear to be glued to the head. • In many people, there is a width of about one finger of space between the back of the ear and the head. • Once the ear is positioned and smoothed into the head, the small triangular form of the tragus must be added. The top of the tragus is just below the helix and rests over the bony auditory meatus.

• Since the external ears are a totally soft tissue feature not based on bone, our best hope is to create anatomically correct, naturalistically placed features.

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• A rule of thumb in art states that the ears are roughly equal in length to the nose. With this in mind, you may wish to adjust the finished ears to correspond somewhat to the finished length of the nose in your reconstruction.

Step 14: Development of the neck • Hardware cloth may be used to form an armature for the shape of the shoulders. • A connection between the shoulders and the head may be built with either flexible aluminium mesh such as that used for gutters or aluminium foil squeezed around the upright portion of the adjustable stand.

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• The neck should not appear as a stiff stovepipe, but rather should tilt forward as it leaves the shoulders due to the curve of the cervical vertebrae. This angle may be more pronounced in women than in men. • The two muscles that most affect the appearance of the neck are the Sternocleidomastoid and the Trapezius. Sternocleidomastoid is more pronounced in men. Trapezius, in the shape of a large trapezoid, provides the gentle angle that connects the neck and the shoulders.

• The forms of the throat caused by the thyroid cartilage, trachea, and other structures should be defined in the sculpture as well as the pit of the neck or suprasternal notch.

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Step 15: Texturing and surface details Texturing • Once the neck is sculpted onto the shoulders, you are ready to add the finishing details. • The tissue depth markers are covered with a thin layer of clay and #40 grade sandpaper can be torn in to pieces and used to press into the clay surface for a skin-like appearance. • Hand stippling with various pointed tools or a toothbrush can also be used to produce skin texture. • This texture is beneficial in the photography process because it knocks off some of the sheen of the clay that can cause glare problems. • Most of the face has some sort of visible skin texture, although the eye area may be more lined, depending on age. • The ears should be left smoother. This may be touched up with a cotton swab dipped in petroleum jelly. Eyebrows • The individual hairs of the eyebrows should be indicated and scratched in the clay with the side of a sculpture tool in a direction that follows the natural growth pattern of the hair.

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• We have no real basis for the eyebrow colour or configuration other than matching a hair specimen if one is available. • In general, the eyebrows tuck slightly under the bony ridge at the bony brow ridge at the medial side (especially in men) and hug the brow bone toward the lateral side, rising above it at the lateral side (especially in women). Colouration • Some reconstruction artists go to great lengths to produce highly detailed and finished products in lifelike colour.

For most law

enforcement reconstruction artists, such processes may not be possible, financially feasible, or timely and remember that you are not working for Tussaud’s Waxworks in London. • Simple, though not as attractive, facial colouration may also be accomplished by use of several types of less expensive media. • Clay colour choice will set the overall skin tone look for the reconstruction from the onset. Darker clay choices may be indicated by certain racial characteristics. • Powdered cosmetics are very handy for applying colour to the eyebrows, the edge of the eyelids, the cheeks or the lips.

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• A light-handed application of cosmetics usually produces a better appearance than too much makeup, which may detract from the face. • It is likely that you have no clue as to whether or not a woman may have even worn makeup.

However, sometimes reasonable

judgements can be made based on the items found with a body. For example, elaborate clothing and jewellery may be a better indicator for more makeup than simple jeans and T-shirt. • Psychological research indicates that 3-D Facial Reconstruction images are more readily recognized with some inclusion of tonal distinction, if not actual colour. Age Indication • The basic facial reconstruction technique favours an age range of 25 to 35 years. • You may have built your entire reconstruction with a certain age range in mind or you may choose to adjust the age upward or downward during the finishing stages.

Adding accessories • If any clothing items or accessories are recovered at the crime scene, they may be evaluated for possible inclusion with the reconstruction. 41

• Clothing is often highly soiled and damaged and may not be usable even if recovered. • Hats, eyeglasses, dentures, jewellery, or other items may, however , greatly contribute to the individualization of the finished work and should be used if possible. • Assistance and permission should be sought from crime scene investigators for the possible cleaning and use of such items.

Step 16: Hair or wig? • Hopefully, you will be fortunate enough to receive a case for reconstruction in which hair was recovered with the body. Sadly, this is not always the case, and the odds for identification decrease the result. • As humans, we place a lot of recognition value on hair and hairstyle and its absence can interfere with the recognition process. • The selection of the hair and hairstyle for a reconstruction may be based on a recovered hair specimen or may have to be totally vague or speculative. •

The hair may be added in the form of hair insertion, or in the form of wig or it may be modelled in clay and coloured in some way. 42

• If a wig is to be used, it should be selected not only for colour, but also for texture, volume and length if known. • It is reasonable that the hairstyle be consistent with the styles that were popular within the time frame of the time of death estimate. • Some Reconstructionists choose to distribute the facial image showing multiple different hair or wig styles.

Practically, this creates

confusion. • If little is known about the hair, focus the attention on facial features. • Cropping tightly in on the face in a photo helps draw attention away from the hairstyle.

Step 17: Photographing the sculpture • The photography of the reconstruction sculpture may be as simple or as elaborate as the artist chooses. • If you are a skilled photographer, you may place more importance on refinement of this part of the procedure, or you can turn the sculpture over to a professional for the photography work. • One of the greatest benefits of the 3-dimensional method is the flexibility of the photography.

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• The usual five views that are shot are frontal, oblique left, lateral left, oblique right, and lateral right. • It is advisable to photograph any of the variations that have been prepared such as open and closed mouth or with and without wig, etc. • In short, any photos of documentation should be made at this time because the sculpture will likely be disassembled and the opportunity for further photos will be lost. • As a freelancer, you will need to disassemble the sculpture in order to retrieve your equipments such as prosthetic eyes, wig and skull stand soon after the project is photographed.

Superimposition During the past 130 years, a number of techniques for comparing images of an individual with their skeletal remains by means of superimposition have developed. Superimposition comparisons have developed into a useful tool for assessing identification of unknown skeletal remains. These techniques fall into three general categories:  Photographic  Video  Computer aided 44

The video type of Superimposition will be dealt in detail, as it is a simpler and much widely accepted method. • Regardless of the technique one uses in superimposition cases, few critical variables must be considered, as positioning, size, distortion, features to be used for comparison, and the defining limits for concluding a possible match or exclusion. • The importance of each of the above variables issues for the results and accuracy of superimposition. • The basic procedure for comparison requires two cameras, one directed at the skull and one directed at the comparison photograph. • The first video camera points directly downward at the skull, perpendicular to the floor. • A second video camera points at the photographic image, parallel with the floor. • Insertion of small dowels or soft rubber cylinders into and projecting from the auditory meati is valuable in aligning the skull with the corresponding region of the ear in the photographic image.

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• Taping of the video superimpositions is initiated after correct scale and orientation are determined. • The two primary video techniques used for documenting the superimposition

and

for

analysis

of

conformity

are

Blending/Fading and Sweeping. • Sweeping technique is preferred to blending or fading technique. • Vertical, horizontal or diagonal sweeps are widely used. • “Box sweep” from the center of the superimposition, which affords careful comparison of the mouth and lower nasal structures, is preferable type. • It is not reasonable practice to attempt to analyze the superimposition in the limited time offered during taping. • For accurate analysis, it is necessary to use a VCR and monitor that produce high resolution, provide for continuous slow-speed viewing, and have single frame advancement and a pause function that maintain the image in a stable format. • Once completed, the comparison is given a ranked score between I and IV. The ranking is based on a qualitative assessment of the number and closeness of anatomically matched areas.

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• Grade I – Represents a close match with strong concordance in all anatomical areas available for comparison, and no area dictates exclusion. • Grade II – Reflects a somewhat less convincing comparison and is described as a reasonable match with strong concordance in most anatomical areas and no area dictates exclusion. • Grade III – Is used in those cases where the comparison cannot be used to definitively exclude a match, but is judged unlikely due to a number of anatomical areas that exhibit poor concordance. • Grade IV – Is assigned when comparison of one or more areas indicates definite exclusion.

Computer Aided Facial Reconstruction The Facial Reconstruction project described here requires three major steps: ξ A computer tomograph scan ξ A stereolithography cast of the skull ξ A skilled technician to model the face in clay using the previous method and to make the moulds.

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A computer tomograph scan • The first step in making the replica of the skull is to have the skull scanned using a Computer Tomography (CT) scan. • The detailed 3-D images of the skull are obtained on the monitor.

A stereolithography cast of the skull • After securing the CT scan data, by a resin casting process called as Stereolithography, two exact resin replicas of the skull are made. • The picture on the left most shows the amount of the brain that is present in the cranium.

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Modelling the face on the cast • The facial reconstruction of the individual can be done on the replica cast of the skull obtained. • Either 2-D Facial Reconstruction or 3-D Facial Reconstruction can be done taking various factors into consideration.

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Conclusion Many law enforcement officers have come to know the power of “Forensic Art”. While not every forensic art attempt is successful, this work does contribute significantly to many criminal investigations.

The

increasing options for image enhancement and modification that computers allow mean this role is likely to escalate in the future. It is incumbent upon all who bear the responsibilities of criminal investigations and prosecutions to understand more about forensic art.

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References 1. Bernard Knight, Forensic Medicine & Toxicology, Simpson’s Forensic Medicine, 11th edition, 1997.

2. Karen T.Taylor, 3-D Facial Reconstruction on Skull, Forensic Art & Illustration, 1st edition, 2001.

3. Rhine.J.S. and Campbell.H.R., Thickness of facial tissues in American blacks, Journal of Forensic Sciences, 25(4), 847-858, 1980.

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