RAGE: RAPE– Forensic Examination

 

The examination of living victims of sexual assaults is the province of the forensic physician or 'police surgeon', in places where such doctors exist. In many countries, any physician may be asked by the police to examine the victim of an alleged sexual offence, but this difficult and onerous task in the living victim is outside the experience of many pathologists - though in some jurisdictions, this function is combined with that of the forensic pathologist. Regrettably, a significant proportion of non-domestic homicides are associated with sexual offences, death occurring either because the woman rejects the sexual approaches or because a sadosexual motive colours an intended murder. The most common mode of killing is either pressure on the neck, head injuries, or, less often, stabbing. In some instances death may be the result of violence associated with the sexual activities themselves, especially in child victims when pelvic trauma may be the immediate cause of death. As with most forensic autopsies, a meticulous external examination is as important - and usually more important - than the internal dissection. The study of the body surface in sexual assaults is similar in both the living and dead and may be divided into general appearances and those of the perineum. The whole body surface should be searched for sexually orientated injuries.

Bruises may be found on the lips and especially inside on the buccal surfaces, from rough kissing. The lips may have been forced back on to the edges of the teeth, causing abrasions, bruises and even laceration of the buccal surface. Swabs should be taken from the mouth in every case before substantial manipulation for examination, to seek evidence of seminal fluid from oral penetration. Though such swabs rarely yield a positive result as to the presence of spermatozoa, modern analytical methods may be able to detect other components of the seminal fluid or the presence of male epithelial cells. Other bruises may be found on the neck, shoulders, breasts and buttocks from oral suction or biting. These are some- what euphemistically termed 'love bites' and may range from minor lesions inflicted from enthusiastic passion to mutilating bites of a sadistic nature. Suction lesions may comprise a circular ‘or oval area of bruising, in which the damaged zone consists of many small intradermal petechial haemorrhages caused by sucking the skin into the mouth, the reduced air pressure rupturing the small vessels. There may be semilunar marks at the periphery from the lips, and there may be associated teeth indentations or abrasions. Such suction marks are often seen at the sides of the neck, below the ears, on the upper shoulder, and on the upper part of the breasts and around the nipples.

the main features are abrasions or bruises matching the dental arches, often with discrete marks from each tooth. These may be linear if the teeth are scraped down the skin in closing the jaws. They may be superficial or deep enough to penetrate the skin as lacerations. The latter are especially common at the nipples in sexual assaults, and the nipple and part of the areola may even be partly or wholly amputated. In sexual homicides, it is essential to obtain expert forensic odonatological advice, if at all possible. In any event, photo- graphs and measurements must be taken of these injuries and, if practicable, a cast of any teeth indentations for later comparison. Before any handling of the lesions, swabs should be taken of the surface in an effort to recover saliva, which - if the assailant was a 'secretor' - may be tested for blood-group- specific substances.

Apart from bruises that may be associated with the fatal assault, such as throat or head injuries, some bruises are indicative of the sexual motivation. The breasts are often manually squeezed and manipulated, causing discoid bruises of 1-2cm on any part, especially around the nipples. Linear abrasions, usually from fingernails, may also be present. Bruises may also be seen on the thighs and buttocks, from struggles to achieve intercourse. Both the outer and inner sides of the thighs may be bruised and scratched: a typical area is the inner aspect of the upper thigh, where the legs are manually forced apart. There may be bruising around the anus from fingers opening the buttock cleft to achieve either anal or posterior vulval penetration. Where the assault takes place on a hard or uneven sur- face, bruises and abrasions may be seen on the back, especially the shoulders and buttocks. If outdoors, there may be marks from stones or sticks and remnants of vegetation, such as leaves, and grass and green staining may be adherent to the skin, together with earth or dirt. Examination of the clothing is usually a function of the forensic scientist ('criminalist'), but when the pathologist examines the body in situ, he will naturally note damage, disarray and foreign material on the garments.

The hands should be carefully examined, as in all assaults. The fingernails, especially the often longer and manicured nails of younger women, may be broken from a struggle. Occasionally, there are hairs or fibres trapped in nail splits, which may have come from the assailant or his clothing. At autopsy, the nails should be cut closely to the junction with the fingers and all parings carefully collected for forensic laboratory examination. It is rarely necessary to collect those from each finger in individual packets, but each hand should be identified separately. Some pathologists or scientific officers prefer to scrape out the space under each nail with a pointed orange-stick or toothpick, carefully retaining any debris. The reason for this interest, especially in sexual assault victims, is that they may have scratched their assailants and have blood, or even skin parings, under the nails that can be identified as to blood group or individually specific DNA characteristics. Signs of head injury and throttling are dealt with elsewhere, but some fatal trauma may be sexually orientated, especially knife injuries. Sadistic cutting or stabbing may be inflicted on sexually significant areas, especially the breasts, buttocks, perineum and lower abdomen. The vulva itself may be mutilated. These may be slashes or deeply penetrating stabs, often multiple and indeed numerous. They may be arranged in a pattern or may be mutilating as when whole breasts are amputated.

Once the pathologist has examined all the external general injuries, attention should be turned to the perineum. As with the clinical examination of sexual offences, a set routine should be used, as the incorrect order may lose valuable forensic evidence. The vulva and anus should be inspected externally and laceration, swelling, bruising, bleeding and discharge noted. Any blood or suspected semen stains anywhere on the body or clothing should be sampled either by the pathologist or by the forensic scientist or scene of crime police officer. The pubic hair should be examined for foreign material, hairs, vegetation and dried seminal stains, and samples of hair and combings taken. The hair may be combed using a fine comb with the base of the teeth packed with cotton-wool to trap any loose fibres. Dried stains on hair may be cut away and placed in clean folded paper in an envelope, or plastic bag for transit to the laboratory. The vulval labia may show clear signs of trauma, especially in children. In forcible rapes, especially in young persons, there may be external signs of perineal tears, with laceration of the margin of the vaginal introitus or anus, sometimes causing a complete rip between the two orifices.

Caution must be used in interpreting the degree of dilatation of the anus in a dead body, as the sphincter can become patulous and wide open as a normal post-mortem change. Unless the dilatation is very marked, the sole finding of an open anus in the absence of abrasion, bruising, or semen is difficult to sustain as proof of anal penetration. This applies to children as well as adults; in fact, post-mortem dilatation of the anus is particularly noticeable in children. Once external examination and assessment has been made, samples should be taken for forensic biological testing, for the presence of semen and venereal infection, as well as samples for DNA profiling, which may be able to distinguish between any semen present and the vaginal secretions. If any fluid is running from the vulva or anus, it should be picked up with clean pipettes and preserved in the smallest available tube, to prevent drying from evaporation.

The order of the autopsy may be determined by the nature of the death. The fatal injuries, such as strangulation or head injuries, may be dealt with first or the pelvic region may command prime attention. The autopsy incision should be similar to that described for the examination of deaths associated with pregnancy, with an incision circumscribing the perineum, removal of the anterior part of the pelvic bones and the extraction of all the pelvic organs in continuity from ovaries to vulva and anus. This block of tissue is then dissected separately. Before this is done, the bladder should first be emptied of urine (either by catheter or through a small incision in the fundus) and the fluid retained for toxicological analysis, especially for alcohol.

 

The vagina should be opened with large scissors, the track of the cut depending on the assessment of any injuries seen on external examination. If there are tears or bruises in the vulva or vagina, the cut should be orientated to avoid them wherever possible; the anus is later dealt with in a similar way. The vagina is laid open to the posterior fornix and all injuries carefully examined and photographed. The cervix and uterus are examined in the same way. Injuries may be of all types, from mere reddening or swelling to complete disruption of the vaginal canal. This may occur in small children from sheer brutality of penetration, especially if there is gross disproportion between the adult penis and infantile canal. It may also occur from instrumental injury, as it is by no means uncommon for deliberate incised wounds to be made. Vaginal injuries, especially by instrument, may continue up into the abdominal cavity, either via the posterior fornix or lateral vaginal walls. This will have been examined through the abdominal.autopsy incision before removal of the pelvic organs.

 

As in clinical forensic practice, there is little difficulty in interpreting gross sexual interference, but problems arise when only minimal evidence is present in a death (traumatic or otherwise) where the circumstances suggest some sexual offence or activity. In such cases, the following questions need to be answered, in the light of all the available findings at the end of the autopsy and ancillary investigations:

-          Is there any evidence of sexual intercourse at any time - that is, absence of virginity as determined by an intact hymen? This does not exclude sexual activity short of penetration and technically rape can occur from even the minimal passage of a glans between the labia, which does not affect the hymen. Old intercourse may be assumed from healed hymenal tears with epithelialized 'carunculae myrtiformesl at the margins, though the prolonged use of tampons and manual manipulation can also tear a hymen. Evidence of previous pregnancy, such as abdominal striae, old damage to the cervix and breast changes are almost incontrovertible evidence of previous sexual intercourse.

-          Is there evidence of recent sexual intercourse? A recently ruptured hymen, with swelling, a raw epithelialized edge and bleeding may be found, though admittedly it is relatively uncommon except in children and previously virginal young persons. The labia may be red and inflamed with slight oedema of the vaginal introitus if it is the first episode, or if there is disproportion between an adult man and a young person, even in voluntary sexual connection. The presence of semen on swabs is the best evidence, though with the use of condoms it may be absent. After vasectomy, though no sperms will be present, chemical and enzyme tests for semen remain positive. The presence of venereal disease, especially gonorrhoea, is presumptive evidence of intercourse, though it can be contracted other than by sufficient penile penetration to constitute rape.

-          If recent intercourse has taken place, was it by force? This may be all too obvious in the presence of !gross injury, especially in small children. Where vaginal or rectal tearing has occurred, or where there is obvious abrasion, bruising or laceration of the vulva, anal margins or perineum, then this can hardly be compatible with voluntary intercourse. The possibility of sexually motivated injury without actual penile penetration must be considered when no semen can be recovered, as equally severe damage can be caused by digital or instrumental trauma. All kinds of foreign objects can be forcibly introduced into the vagina and rectum, and are not infrequently employed by sadistic and perverted killers.

Where injury is relatively slight and confined to hyperaemia and oedema of the vaginal or anal entrances - and where abrasion and bruising of the vulva is slight (even including fingernail scratches), although the presumption is that intercourse was by force, the possibility still exists that it was voluntary though overenthusiastic, unless, of course, the victim was a small child.

The detection of semen depends upon the following methods:

-          Naked-eye and lens recognition is a screening method which may identify suspicious stains on clothing, skin and pubic hair. Liquid semen leaking from the vagina or anus may be obvious, though leucorrhoeic  vaginal discharge may be mistaken for seminal fluid. Dried seminal stains are stiff and rather silvery, depending upon the nature and cdlour of any fabric they may be upon. On the skin they flake off readily and can easily be lost if not carefully lifted with a blade or needle into a container. Dried stains on hair should be retrieved by cutting away the clump on which they lie. Suspect smears on skin may be collected by gentle rubbing with a plain cotton-wool swab that has been moistened with water or saline. All material should be examined as soon as possible after collection.

-          Examination under ultraviolet light causes seminal stains to fluoresce a bluish-silver, but many other biological fluids and vegetable juices give false-positive results. Many detergents, such as washing powders, also produce a confusing background fluorescence. The method is a useful screening process but cannot be used as definitive evidence of the presence of semen. Areas that fluoresce, especially on fabric, should be outlined to identify them for more specific testing.

-          Enzyme reactions are valuable, and though not absolute proof, are strong presumptive evidence of the presence of semen. They depend on detecting high concentrations of acid phosphatase originating in prostatic secretion. Acid phosphatase activity in semen is 500-1000 times greater than in any other normal bodily fluid. Also, vaginal fluid contains endogenous acid phosphatase showing considerable variation in activity depending on various factors, which complicates the interpretation of the findings. There are several methods of detecting phosphatase, including a rapid commercial 'spot' test, which should not be used as hard evidential proof.

-          Immunological methods, where animal antihuman semen sera are set up against extracts of the stain. These - techniques can only be used by trained laboratory staff. Prostate-specific antigen (PSA, p30) is a glycoprotein produced by the prostatic gland and is found in seminal plasma, male urine and blood, but not in any tissues or fluid of-the female body. A positive PSA finding is a reliable indicator of semen regardless of the presence of spermatozoa or elevated acid phosphatase level. Simple and sensitive methods have been developed for analysis of the presence of PSA.

Other serological techniques may be able to determine the blood group of the semen if the ejaculator was one of the 80 per cent of the population who are 'secretors' - those who pass blood-group antigens into their saliva, sweat and semen. A problem for the forensic serologist is the admixture of semen with biological fluids from the victim, in the form of vaginal secretion and blood, but this is a complex technical matter that is usually outside the remit of the forensic pathologist, though he needs to be aware of the potential difficulties. Recent developments have now added the DNA technique to the armamentarium of the forensic biologist; this is a remarkable advance, especially in sexual offences, as the previous problems of blood group and enzyme typing caused by the admixture of semen and vaginal secretion can now be solved in many instances. The sensitivity of detection and identification has also been enormously enhanced by amplification techniques, such as PCR (polymerase chain reaction). Y-chromosome short tandem repeat (STR) markers have been successfully used to analyse mixed stains with a male component.

One modern problem in using spermatozoa retrieval is the widespread and increasing incidence of vasectomy as a method of male contraception, so the seminal fluid contains no sperm; this also occurs naturally in azoospermic men. The phosphatase and some serology tests are unaffected by vasectomy. Fluorescent in situ hybridization (FISH) has been suggested as a sensitive and specific test for the detection of male epithelial cells in the post-coital vagina up to one week. Y-chromosome- positive epithelial cells have been identified in vaginal swabs even in cases with no ejaculation.

 

Acknowledgements:

www.aived.nl    AIVD – @Erik Akerboom ©

www.politie.nl  Politiekorpschef  @Janny Knol©

www.politie.nl WEB Politie - @Henk van Essen©

 

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