Facial reconstruction in Forensics

Facial reconstruction in Forensics – In 1935 in Ruxton case, the Skull photo superimposition technique was applied by Brash and Glaister in 1935 in Ruxton case. This technique determines whether the skull in question is the same as the skull of the person who is in the photograph. The photograph need not be front view of the face; even lateral and semi-lateral view of face can be used. A recent photograph is better. If the negative of photograph is not available, negative of the available photograph is prepared by recopying it.

The photograph is enlarged to natural size from the presence of some standard thing in the photograph of the missing person to indicate the scale in facial reconstruction. In the absence of a standard for the measurement of face in the photograph, photographs of the skull and face are superimposed by adjusting the magnifications until the interpupillary distances correspond, on the assumption that the interpupillary distance in one individual is the same always when the eyes move in different directions.

The negative is placed under the ground-glass of camera and salient features of the face are marked out carefully on the glass. The soft parts are removed from the skull. A comparison can be made even in the absence of the lower jaw. The skull is mounted on an appropriate skull rest, so as to align as accurately as possible with the outline of the head on the ground-glass in the corresponding portrait, making due allowance for the soft tissues covering the bone.

facial reconstruction

facial reconstruction

The distance of the camera is adjusted so that the one inch scale on the ground-glass of the camera is exactly equal to the scale on the skull. This, when photographed, gives a life-sized negative of the skull. The negatives of the photographs and the skull are superimposed by aligning the characteristic points in the negatives for facial reconstruction.

The following points are then compared.

(1) The eyes within the orbital plates, with the two pairs of canthuses properly aligned.

(2) The nasion.

(3) The prosthion in the central line.

(4) The nasal spine in the center which is a little above the tip of the nose.

(5) The lower border of the nose.

(6) The lower border of the upper jaw, i.e., below the tip of the nose.

(7) The zygomas below the eyes.

(8) Supraorbital ridges.

(9) Angle of the jaw.

(10) External auditory meatus.

(11) Teeth.

The two superimposed negatives are then photographed on bromide paper. The resulting superimposed photograph brings out the points of similarity or dissimilarity between the photograph and the skull. The superimposition is correct, if the outlines and the size of the skull accurately correspond to the face in the photograph.

A clear effect of the superimposed area can be obtained by combining the negative of the skull with the positive of the portrait. For this, positive portrait and negative of the skull are rephotographed on X-ray film, thus producing a transparent positive of the skull. Finally, the two films are bound together in register and thus superimposed; they are then rephotographed on X-ray film by transmitted light to do the facial reconstruction.

This test is of a more negative value, because it can definitely be stated that the skull and the photograph are not those of the same person. If they tally, it can only be stated that the skull could be that of the person in the photograph, because of the possibility that another skull of that size and contour may tally with the photograph.

Video Superimposition in facial reconstruction

The skull is mounted on an adjustable support allowing movement in three planes. The photograph is also mounted similarly. A colored video camera is aligned at right angles to the photograph and a second camera is aligned to the skull. The individual video signals from each camera are fed into a vision mixer.

By this superimposition and negative simulation can be done. In cases where sufficient anterior teeth remain on the cranium, and a photograph showing suspected deceased smiling is available, image superimposition can be done. Digital image manipulation technique is better.

IDENTIFICATION BY RECONSTRUCTION OF FEATURES

(1) His, determined the average thickness of the soft parts of the face at a series of fifteen, i.e., nine median and six lateral pre-determined points. Using these data, attempts at reconstruction have involved the application of clay or plastic in appropriate thickness over the landmarks, contouring the facial outlines and building up the soft features of the nose, mouth and ears. The restorer must rely on various artistic cannons, personal experience, skill and intuition. It may help to eliminate certain suspected persons, or support an identification based on other skeletal evidence.

(2) 20,000 measurements can be taken using video and laser equipment, which can be stored in 30 seconds. The data from an unknown skull are then electronically ‘clothed’ with standard soft tissues from the memory bank and modified on screen to produce various images, which can be rotated electronically to produce various profiles. To recognize a missing person by a viewer, a variety of stored eyes, ears and noses can be added, and any feature altered instantaneously.

COMPUTER PICTURES in facial reconstruction

Several curves for each of facial creases, prominences, shape of forehead, eyes, ears, nose, cheek, lips, teeth projections, scalp hair, mustache and beard are stored in a computer. Depending on the descriptions of the different features by the persons who have seen the criminal, hundreds of varieties of face can be drawn on the screen of the computer within a few minutes.

An almost exact appearance of the face can be drawn by additions and alterations of curves, which can be printed out. A major problem is that features which give individuality to a face, such as the eyes, lips and facial hair, are not very dependent upon the underlying bone structure.

PHYSIO GNOMIC RESTORATION in facial reconstruction

(1) Sculptural to give a three-dimensional bust and

(2) artistic to give drawing in two views, facial and profile, to show cephalic and facial details.

Both methods try to achieve an individual likeness which will lead to identification of the suspect.

BONE COMPARISONS in facial reconstruction

When previous X-ray films of the skull are available for comparison with postmortem films, measurements of the skull and a detailed comparison of the frontal, sphenoidal and maxillary sinuses, sella turcica and mastoid area are useful for identification in adults. No two pairs of sinuses are the same. The frontal sinuses are individual specific. The scalloped upper margins of the sinuses are used for comparison, these being smaller and more numerous in the female. The sphenoid complex and the mastoid area are also very useful criteria of individuality.

Abnormal bones, such as cervical and lumbar ribs, wormian bones (small bones in the skull caused by abnormal suture patterns leaving islands of bone surrounded by sutures, sometimes referred to as (‘sutural’ or ‘intrasutural bones’), and sesamoid bones (bones included in tendons, frequently seen in the hands and feet) niay provide definite points for comparison and positive identification.

The trabecular fine structure of all bones (excluding the bones of the skull) may be defined with enough precision by xerox-radiography to permit comparisons. Congenital abnormalities, e.g., absence of bones, displacement and malformations are very rare. Comparison of the lateral skull x-ray and x-rays of the upper ribs, humeri and femurs can provide useful information based on the pattern of the concellous bone, when previous radiographs are available.

The contours of the second rib are unique. Fusion of the ribs may be noted. Radio graphs of the carpal bones show individual details. The presence of surgical prostheses or of supportive implants, such as plates, pins or orthopedic screws and of trephine or other operative defects of the skull is very useful in facial reconstruction.

Dental radiography may show significant root shapes, socket outlines or abnormalities of tooth eruption, development or decay. Unusual calcification of tuberculous origin in the lungs or lymph nodes, or due to degenerative changes in the uterus, calcified mitral or aortic valve, phlebolith, granuloma, etc. are characteristic.

SKULL SUTURE PATTERN AND VASCULAR GROOVES in facial reconstruction

The suture patterns of the skull appear to be quite individualistic. The sagittal and lambdoid sutures are especially complicated and quite different from one person to another. However, the suture patterns are not useful for comparison because

(1) the sutures close, and the pattern obliterated with age, and

(2) the suture patterns are not well demonstrated in those postmortem X-ray films most commonly available.

The vascular grooves, such as those related to the middle meningeal vessels, are much more apt to be visible in X-ray films than are the suture lines, are useful for comparison to establish identity.

X-rays

(1) They are useful in identification by determining the sex, age, superimposition, and identification of the person by detecting old fractures, diseases, or congenital bony changes.

(2) In investigation of cases of battered baby syndrome, burns, drowning and decomposition.

(3) To detect air embolism, and pneumothorax.

(4) To locate missiles in the body, direction of firing, depth of the wound and type of firearm.

(5) To detect parts of the mechanism of bombs and explosive devices that are embedded in the tissues.

(6) To locate foreign bodies, bullet emboli, etc.

(7) To detect fractures.

(8) To detect pregnancy, foetal death or abnormality, hydatidiform mole, Etc.

(9) Electrocution.

(10) Lead poisoning.

VEINS ON THE BACK OF HANDS

Tamassia suggests that there is complete individuality in the arrangement of the veins of the back of the hands.

STOMACH PICTURES

Barium meal X-ray of the stomach is said to be individual.

NAILS

Longitudinal striations are present on both the convex and concave surfaces of human fingernails and toenails. Parallel striations on the surface of the fingernail are significantly different for each individual. The striation pattern becomes more prominent with advancing age, but remains otherwise unchanged during the life of the person. Nails grow at the rate of about 3.2 mm. per month.

DEFORMITIES in facial reconstruction

They may be congenital or acquired. Congenital deformities, such as hare-lip, cleft palate, talipes, polydactylism, web-fingers or toes, undescended testicles, etc. are frequently treated surgically, and are therefore losing some of their past importance. Old amputations, spinal defects, old fractures and deformities of the bones and nails, either from injuries or disease and surgical prostheses, such as implanted artificial heart valves, plates in the skull, etc., should be described.

Mongolian spots (congenital marks) appear as dark blue or violet, single or multiple macules in the lumbosacral region in some young children of Asiatic and African origin.