Forensic Medicine and Anthropology Questions and Answers

Answer: A

The abrasion is a graze.

A graze (sliding or brush abrasion) is produced when a broad area of skin slides against a rough surface, as when a pedestrian is dragged along a road. The epidermis is scraped away, and the heaped-up skin tags at one end show the direction of movement.

A scratch is a linear abrasion made by a pointed object, such as a fingernail or thorn. A pressure abrasion and an imprint (patterned abrasion) are made by direct, crushing force at right angles to the skin, as with a ligature or a tyre, not by sliding.

Answer: D

The first internal organs to putrefy are the larynx and trachea.

Putrefaction is driven largely by bacteria. The lining of the larynx and trachea is soft and in contact with air and with organisms from the mouth and throat, so it is the first internal tissue to discolour and decompose.

Organs with dense muscular or fibrous tissue resist much longer: the heart and kidneys putrefy late, and the uterus and prostate last of all. The gall bladder, though its contents stain nearby tissue early, is not the first organ to putrefy.

Answer: A

The basilar suture usually closes between 18 and 25 years.

The spheno-occipital synchondrosis joins the basi-sphenoid and the basi-occipital at the base of the skull. It is one of the most useful markers in age estimation because it fuses in late adolescence and early adulthood, generally between about 18 and 25 years, somewhat earlier in females than in males. An open basilar suture indicates a young person; a fused one indicates an adult.

The vault sutures (sagittal, coronal, lambdoid) close much later and more variably, from the thirties onward, which is why the older age ranges are tempting but belong to them, not to the basilar suture.

Answer: A

The patella and fabella are sesamoid bones.

Sesamoid bones develop within tendons where they pass over a joint or bony prominence, protecting the tendon and improving its mechanical advantage. The patella (kneecap) lies in the tendon of the quadriceps femoris and is the largest sesamoid bone. The fabella is a small sesamoid bone found in some people in the lateral head of the gastrocnemius behind the knee.

Pneumatic bones contain air spaces (such as the maxilla and frontal bone), miniature long bones are the metacarpals, metatarsals and phalanges, and flat bones include the skull vault, ribs and scapula.

Answer: C

The key's estimate is 2 to 3 days.

In hot weather, houseflies and blowflies lay eggs on a body within hours of death, especially at the natural orifices and wounds. The eggs hatch into maggots in roughly 8 to 24 hours, and the maggots grow over the next few days before pupating at around 4 to 5 days. Putrefaction is also rapid in summer, with greenish discoloration, bloating and marbling well developed by the second or third day. A putrefied body infested with maggots in summer therefore points to about 2 to 3 days.

One day is too early for established maggot infestation with putrefaction, while 10 to 15 days would show pupae, empty pupal cases or advanced decomposition.

Answer: C

Turner's syndrome has the sex chromosome constitution XO, printed 'OX'.

Persons with Turner's syndrome have 45 chromosomes, with a single X and no second sex chromosome (karyotype 45,X). They are phenotypically female, with short stature, webbed neck, widely spaced nipples, ovarian dysgenesis and usually infertility. In buccal smears they are Barr body (sex chromatin) negative, like normal males.

XY is the normal male, XYY is the 'supermale' (Jacobs) syndrome, and XXX is triple X (superfemale) syndrome. XXY, which is not offered, is Klinefelter's syndrome.

Answer: C

In adipocere formation body fats change into a soapy, waxy substance.

Adipocere (saponification) is a modification of putrefaction that occurs in bodies lying in water or in damp, warm, airless conditions. Body fat is hydrolysed into fatty acids, which combine with sodium and potassium, and later calcium and magnesium, to form a greyish-white, soft, greasy, waxy material with a rancid smell. It can preserve the body's shape and injuries for long periods.

Muscles do not turn into fat; blood turning to serum and tendons into gelatinous mass describe other changes of decomposition.

Answer: C

The key dates a green bruise at 4-5 days.

As blood in a bruise breaks down, haemoglobin is converted to haemosiderin, biliverdin and bilirubin, and the colour changes in a rough sequence: red at first, then blue or purple over the first days, greenish around the fourth to sixth day, yellow around the seventh to twelfth day, and fading by about two weeks. Indian forensic medicine textbooks give green at about 4-5 (or 5-6) days.

The colour sequence varies with the depth and size of the bruise and the person's age and health, so it gives only an approximate age. But green is a mid-stage colour, later than the red or blue of 1-2 days and earlier than the yellow of 7-12 days.

Answer: C

The method not used for hymen examination is through urethra.

In examining the hymen in suspected sexual assault, the examiner may use a Glaister Keen rod, a glass rod with a small glass ball at the end, introduced into the vagina so that the hymen is spread over the ball and tears can be seen; a Foley's catheter with an inflated balloon can be used in the same way. In some cases a finger in the rectum is used to push the hymen forward for inspection.

The urethra is a separate passage, so the hymen cannot be examined through it.

Answer: B

Blue discoloration of the nails in asphyxia is cyanosis.

Cyanosis is a bluish colour of the skin and mucous membranes caused by an increased amount of deoxygenated haemoglobin in the blood, more than about 5 g/dl. In asphyxial deaths it is seen in the lips, ear lobes, fingertips and nail beds, and is one of the classic signs along with petechial haemorrhages and congestion.

Petechial haemorrhages are small pinpoint bleeds, often on the conjunctivae and face, not a blue colour of the nails. Oedema is swelling from fluid, and 'indigosis' is not a medical term.