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 DeathThe causes of the death which are

forensically related can be broadly grouped in to three categories:

Suicidal ---- also called as self-induced death.Ex. Railway track

suicide, Gun shot suicide, CO inhalation, etc., Homicidal ---- this is

the type of death caused by others.Ex. Sexual assaults, Road traffic

accidents, Tortures, etc., 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

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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

deathAntemortem – before deathPerimortem – near or around the time

of death.The early changes after death.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

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hours and advances until approximately twelve hours, when it is

generally complete.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.Forensic ArtForensic 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

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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.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 three-dimensional facial reconstructions from skull.

Facial ReconstructionFacial 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

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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 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.

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.

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 Reconstruction3-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.

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.

Combination method --- The most advantageous method for use in

law enforcement is probably a combination of both the anatomical

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approach and the tissue depth approach. Few tissue depth data are

utilized.

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

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Vinyl machine eraser strips

#40 grade sand paper

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

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Connecting the tissue depth markers to establish facial contours

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.

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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-to-

bone 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.

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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

2. Glabella – The most prominent point between the supraorbital

ridges in the midsagittal plane

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

nasal bones

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

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

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

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

forehead

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

margin or border

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

or border

14. Inferior malar – The lower portion of the maxilla

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

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

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

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

the teeth occlude

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.

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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.

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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.

“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”.

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“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.

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.

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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.

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

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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.

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.

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.

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.

Continue to shape the concha more smoothly and form the

antitragus, intertragal notch and lobe.

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.

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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.

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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

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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 ReconstructionComputer Aided Facial Reconstruction

The Facial Reconstruction project described here requires three major steps:

A computer tomograph scan

A stereolithography cast of the skull

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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