Medical PG Online Test Series 125 – Forensic Medicine

View of the hard palate showing palatal rugae. Torus palatinus, a bony protrusion on the palate is also visible.

• Primary rugae are 5-10mm or more.
• Secondary rugae are 3-5mm.
• Fragmented rugae are less than 3mm.
• Palatal rugae are unique to each person.
• Harrison Allen, in 1889, suggested the use of palatal rugae for identity verification.

Ref: Textbook of Forensic Medicine and Toxicology, V. V. Pillay, 14th edition, p77.
Image credits: Based on image by Dozenist.  Licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. en.wikipedia. org/wiki/File:06-06-06palataltori.jpg

• Superfecundation is fertilization of 2 ova discharged from the ovary at the same period by 2 separate acts of coitus committed at short intervals.
• Both ova do not always develop to maturity.
• One foetus may get aborted early or die and get retained until labour.

• Fertilization of a second ovum in a woman who is already pregnant is superfoetation.
• It can occurs in a bipartite uterus.

Ref: The Essentials of Forensic Medicine and Toxicology, Dr. K. S. Narayan Reddy, 26th edition, p343.

• Kevorkian sign is a postmortem change that occurs in the retinal vessels.
• It is characterised by fragmentation of blood column in the retinal vessels.
• It appears within minutes after death and lasts for about 1 hour.
• It can be visualised by using an ophthalmoscope.

Ref: The Essentials of Forensic Medicine and Toxicology, Dr. K. S. Narayan Reddy, 26th edition, p132.

• The combination of alopecia & skin rash, painful peripheral neuropathy and confusion with lethargy are known as ‘Thallium triad’.
• It is indicative of chronic thallium poisoning.
• Other symptoms include dystrophy of nails (Mees’ lines; also seen in arsenic poisoning), cardiovascular symptoms like hypertension and cardiomyopathy, ophthalmological symptoms like ptosis, ophthalmoplegia, nystagmus, keratitis, lens opacity and optic atrophy.

Ref: Textbook of Forensic Medicine and Toxicology, V. V. Pillay, 14th edition, p414.

• Some shotguns have a small portion of their bore near their muzzle end rifled.
• There are called paradox guns.

Ref: The Essentials of Forensic Medicine and Toxicology, Dr. K. S. Narayan Reddy, 26th edition, p181.

• Danbury tremor is a classical and consistent manifestation of mercury poisoning.
• It is a coarse intentional tremor interspersed with jerky movements.
• It begins in the hand and progresses to lips, tongue, arms and legs.

Ref: Textbook of Forensic Medicine and Toxicology, V. V. Pillay, 14th edition, p406.

• Lichtenberg figures is an external lesion seen in lightning strike.
• Superficial, thin, tortuous markings are seen on the skin.
• When the pattern resembles a fern leaf, it is called Lichtenberg figures or filigree burns.

Ref: Textbook of Forensic Medicine and Toxicology, V. V. Pillay, 14th edition, p198.

• Some poisons impart characteristic colourations which is known as postmortem lividity.
• Carbon monoxide – Cherry pink
• Hydrogen sulphide – Greenish blue
• Phosphorous – Brown

Ref: Textbook of Forensic Medicine and Toxicology, V. V. Pillay, 14th edition, p369.

• The common blood groups ABO, MNS and Rh systems can be determined in a blood stain by Lattes crust method.
• Luminol spray is used to identify blood stains which are no longer visible due to washing of crime scene.
• Kastle-Meyer test is used to identify visible blood stains.
• Haemin crystal test is a confirmatory test for blood stains.

Ref: Textbook of Forensic Medicine and Toxicology, V. V. Pillay, 14th edition, p320-323.

• Peppering – Grains of gunpowder being driven into the skin.
• Smudging – Superficial deposit of smoke on the skin.
• Lead ring / Metal ring around entry wound – Deposition of lead or other metal in the skin.

Ref: Textbook of Forensic Medicine and Toxicology, V. V. Pillay, 14th edition, p161.