Identification — MCQs

Identification Indian Medical PG Practice Questions and MCQs

Question 31: Absolute proof of monozygosity is determined by?

A. DNA fingerprinting (Correct Answer)
B. Intervening membrane layers
C. Sex of the babies
D. Reciprocal skin grafting

Explanation: **Explanation:** **1. Why DNA Fingerprinting is Correct:** DNA fingerprinting (DNA profiling) is the gold standard and absolute proof for determining monozygosity. Monozygotic (identical) twins originate from a single fertilized ovum (zygote) that splits into two. Consequently, they possess an identical genetic makeup. DNA fingerprinting analyzes highly variable regions of DNA (STRs/VNTRs); since monozygotic twins share 100% of their genetic material, their DNA profiles are identical, providing definitive proof. **2. Why Other Options are Incorrect:** * **Intervening membrane layers:** While a monochorionic placenta strongly suggests monozygosity, about 25-30% of monozygotic twins are dichorionic (if the split occurs within 3 days of fertilization). Therefore, membrane configuration is suggestive but not absolute proof. * **Sex of the babies:** While monozygotic twins are always the same sex, dizygotic (fraternal) twins can also be the same sex. Thus, sex alone cannot differentiate between the two types. * **Reciprocal skin grafting:** Historically, successful cross-grafting (no rejection) was used to indicate monozygosity because identical twins share the same HLA antigens. However, this is an invasive, outdated clinical test and is no longer considered the "absolute proof" in the era of molecular genetics. **High-Yield Facts for NEET-PG:** * **Superfecundation:** Fertilization of two ova within the same menstrual cycle by sperm from separate acts of coitus (can be different fathers). * **Superfetation:** Fertilization of two ova in different menstrual cycles (rare in humans). * **Dermatoglyphics:** Fingerprint patterns in monozygotic twins are **similar but not identical** due to intrauterine environmental factors; therefore, fingerprints cannot be used to prove monozygosity, but DNA can. * **Mixed Dentition:** Like fingerprints, dental patterns show similarities but are not identical in monozygotic twins.

Question 32: Dactylography is:

A. Surest sign of identification (Correct Answer)
B. Probable sign of identification
C. Presumptive sign of identification
D. Doubtful sign of identification

Explanation: **Explanation:** **Dactylography** (also known as Dermatoglyphics or Fingerprinting) is the study of the ridge patterns on the skin of the fingertips. It is considered the **surest sign of identification** because it fulfills the two most critical criteria for personal identification: **Uniqueness** and **Permanence**. 1. **Why Option A is Correct:** * **Uniqueness (Individuality):** No two individuals, including monozygotic (identical) twins, have identical fingerprints. The Galton details (minutiae) are unique to every person. * **Permanence (Immutability):** These patterns appear between the 12th and 16th week of intrauterine life and remain unchanged until the skin decomposes after death. Even if the skin is superficially injured, the pattern regenerates exactly as before. 2. **Why Other Options are Incorrect:** * **Options B, C, and D:** These are incorrect because "Probable" or "Presumptive" signs (like scars, tattoos, or deformities) can be altered, surgically removed, or shared by multiple people. Dactylography, however, provides **absolute** proof of identity in a court of law. **High-Yield Clinical Pearls for NEET-PG:** * **Galton’s System:** The classification of fingerprints is based on four primary patterns: Loops (60-70%, most common), Whorls (25-35%), Arches (6-7%), and Composites. * **Poroscopy (Locard’s Method):** The study of the number, size, and distribution of sweat pores on the ridges. It is used when only a fragment of a fingerprint is available. * **Adermatoglyphia:** A rare genetic condition where an individual is born without fingerprints (often called "immigration delay disease"). * **Legal Requirement:** In India, 16 points of similarity (Galton details) are generally required for a match in court, though many experts consider 8–12 points sufficient.

Question 33: The technique of identification based on the evaluation of friction ridges on the volar areas is called as?

A. Dactylography
B. Poroscopy
C. Ridgeology (Correct Answer)
D. Rugoscopy

Explanation: **Explanation:** **Correct Answer: C. Ridgeology** Ridgeology is the holistic study of the friction ridge skin on the volar surfaces (palms and soles). It involves the evaluation of all aspects of the ridges, including their flow, characteristics (minutiae), and the spatial relationship between them. While dactylography focuses specifically on fingerprints, **Ridgeology** is the broader, scientific term used for the systematic study of these unique patterns for identification purposes. **Analysis of Incorrect Options:** * **A. Dactylography (Dactyloscopy):** This is the study of fingerprints specifically for identification. While related, it is a subset of the broader evaluation of friction ridges. * **B. Poroscopy:** This is the study of the size, shape, and distribution of sweat gland pores on the friction ridges. It was pioneered by Edmond Locard and is used when only fragmentary prints are available. * **C. Rugoscopy (Palatoscopy):** This refers to the study of the permanent transverse mucosal ridges (rugae) on the anterior part of the hard palate. These are unique to individuals and are often used in forensic odontology. **High-Yield Clinical Pearls for NEET-PG:** * **Galton’s Details:** The specific ridge characteristics (ending ridges, bifurcations, dots) used to establish identity. * **Bertillonage:** An obsolete system of identification based on physical measurements (Anthropometry). * **Permanence:** Friction ridges develop between the **12th and 18th week** of intrauterine life and remain unchanged until death (and even after, until putrefaction). * **Cheiloscopy:** The study of lip prints for identification. * **Dactylography** is considered the most infallible method of identification (1 in 64 billion chance of two people having the same prints).

Question 34: Which of the following radiographic views is most appropriate for age determination in children aged 1 to 13 years?

A. Shoulder radiograph
B. Wrist radiograph (Correct Answer)
C. Elbow radiograph
D. Iliac bone radiograph

Explanation: ### Explanation **Why Option B is Correct:** The **Wrist and Hand radiograph** (specifically the non-dominant hand) is the gold standard for age determination in children aged **1 to 13 years**. This is because the wrist contains a high concentration of small bones (8 carpals) and multiple epiphyses (distal radius, ulna, metacarpals, and phalanges) that appear and fuse in a highly predictable, chronological sequence. Methods like **Greulich-Pyle atlas** and **Tanner-Whitehouse (TW2/TW3)** scoring are used to compare these ossification centers against standard templates to estimate skeletal age. **Why Other Options are Incorrect:** * **A. Shoulder radiograph:** The centers around the shoulder (e.g., coracoid, acromion) are more useful for neonatal age or late adolescence (fusion of the humerus head). * **C. Elbow radiograph:** While the elbow is excellent for the **pubertal growth spurt (age 9–14)** due to the specific sequence of the six ossification centers (CRITOE), it is less comprehensive than the wrist for the entire 1–13 year range. * **D. Iliac bone radiograph:** The iliac crest (Risser’s sign) is primarily used to assess skeletal maturity during **late adolescence (14–18+ years)** and is not sensitive for younger children. **High-Yield NEET-PG Pearls:** * **Rule of Thumb:** For age estimation, "Wrist is for children, Elbow is for puberty, and Pelvis/Clavicle is for young adults." * **First Carpal Bone to Ossify:** Capitate (at 1–3 months). * **Last Carpal Bone to Ossify:** Pisiform (at 9–12 years). * **Medio-legal Importance:** Skeletal age is considered more reliable than height or weight for determining the legal age of a minor.

Question 35: Which of the following is used for biometric evaluation?

A. Iris (Correct Answer)
B. Pupil
C. Lens
D. Cornea

Explanation: **Explanation:** **Why Iris is the Correct Answer:** The iris is the gold standard for ocular biometrics because it possesses a highly complex and unique pattern of ridges, crypts, and furrows. These patterns are formed during fetal development (around the 3rd to 8th month) through a process of chaotic morphogenesis, making them unique even between identical twins and between the left and right eye of the same individual. The iris is protected by the cornea but remains visible, and its patterns remain stable throughout a person's life, making it an ideal biometric marker for identification. **Why Other Options are Incorrect:** * **B. Pupil:** The pupil is merely an aperture (opening) in the center of the iris. Its size changes constantly based on light intensity and autonomic nervous system activity, making it unsuitable for stable identification. * **C. Lens:** While the lens has unique characteristics, it is located deep within the eye and undergoes significant changes with age (e.g., sclerosis, cataract formation), rendering it unreliable for biometric tracking. * **D. Cornea:** The cornea is a transparent, avascular layer. While its curvature can be measured (keratometry), it does not possess the intricate, unique patterns required for high-security biometric authentication. **High-Yield NEET-PG Pearls:** * **Bertillonage:** The first scientific system of identification based on physical measurements (Anthropometry). * **Dactylography (Fingerprints):** The most reliable and commonly used method of identification (Galton system). * **Quetelet’s Rule:** States that no two human beings are exactly alike. * **Poroscopy:** The study of sweat gland pores on the ridges of fingertips (Locard’s method). * **Palmoscopy:** Study of palm prints.

Question 36: The Florence test is used to detect which type of stains?

A. Blood stains
B. Seminal stains (Correct Answer)
C. Stains of plant origin
D. Salivary stains

Explanation: **Explanation:** The **Florence test** is a preliminary chemical test used for the presumptive identification of **seminal stains**. **1. Why Seminal Stains is Correct:** The test relies on the presence of **Choline**, a chemical found in high concentrations in human semen. When the Florence reagent (potassium iodide and iodine in water) is added to a suspected stain, the choline reacts with the iodine to form **Choline Periodide**. Under a microscope, this reaction produces characteristic **dark brown, rhombic, or needle-shaped crystals** (often described as "crossed-leaf" or "star-shaped"). **2. Why Other Options are Incorrect:** * **Blood stains:** These are identified using tests like the **Benzidine test**, **Kastle-Meyer test** (phenolphthalein), or confirmatory tests like the **Teichmann** or **Takayama** crystal tests. * **Stains of plant origin:** These do not contain high concentrations of choline and will not yield the specific crystal formation seen in the Florence test. * **Salivary stains:** These are typically identified by detecting the enzyme **Amylase** (Phadebas test). **3. High-Yield Clinical Pearls for NEET-PG:** * **Nature of test:** The Florence test is a **presumptive (preliminary)** test, not a confirmatory one, as choline can be found in other biological fluids (though in much lower concentrations). * **Confirmatory Test for Semen:** The gold standard is the microscopic visualization of **Spermatozoa**. If the sample is aspermic, the **Acid Phosphatase test** (Brentamine test) or detection of **Prostate-Specific Antigen (PSA/p30)** is used. * **Barberio’s Test:** Another crystal test for semen which detects **Spermine** using picric acid, resulting in yellow needle-shaped crystals.

Question 37: What is the term for a double-headed monster?

A. Diplopagus
B. Dicephalus (Correct Answer)
C. Craniopagus
D. Heteropagus

Explanation: **Explanation:** In Forensic Medicine and Teratology, conjoined twins (popularly referred to in older texts as "monsters") are classified based on their site of union. The term **Dicephalus** is derived from the Greek words *'di'* (two) and *'kephale'* (head). It refers to a condition where a single body possesses two separate heads. This occurs due to the incomplete separation of the embryonic disc during the second week of gestation. **Analysis of Options:** * **Dicephalus (Correct):** Specifically denotes two heads on one body. If there are two heads and four arms, it is termed *Dicephalus tetrabrachius*. * **Diplopagus:** This is a general umbrella term for any conjoined twins who are more or less equally developed (symmetrical twins). It does not specify the site of union. * **Craniopagus:** These are twins joined at the **cranium** (skull). They usually have separate bodies and limbs but share a portion of the skull and sometimes brain tissue. * **Heteropagus:** This refers to **asymmetrical** conjoined twins, where one twin is small, underdeveloped, and dependent (the parasite) on the larger, more developed twin (the autosite). **High-Yield Clinical Pearls for NEET-PG:** * **Thoracopagus:** The most common type of conjoined twins (joined at the chest/thorax). * **Ischiopagus:** Joined at the pelvis. * **Pygopagus:** Joined at the sacrum/buttocks. * **Rule of Identification:** In forensic cases involving conjoined twins, identification is crucial for legal purposes regarding birth certificates, inheritance, and if surgical separation is attempted.

Question 38: Species identification is done by?

A. Neutron activation analysis (N.A.A.)
B. Precipitin test (Correct Answer)
C. Benzidine test
D. Spectroscopy

Explanation: **Explanation:** The **Precipitin Test** is the gold standard for **species identification** in forensic medicine. It is an antigen-antibody reaction based on the principle that when an extract of a bloodstain (acting as an antigen) is reacted against a specific antiserum (prepared from a rabbit immunized against human or animal serum), a visible precipitate forms at the junction if the species match. This test is highly sensitive and can identify the origin of blood even in old, dried, or putrefied samples. **Analysis of Incorrect Options:** * **A. Neutron Activation Analysis (N.A.A.):** This is a highly sensitive nuclear process used for **elemental analysis**. In forensics, it is primarily used for detecting trace elements in hair (like arsenic) or identifying gunshot residues (antimony, barium). * **C. Benzidine Test:** This is a **presumptive (screening) test** for the presence of blood. It detects the peroxidase-like activity of hemoglobin but cannot distinguish between human and animal blood, or even certain plant peroxidases. (Note: It is now rarely used due to its carcinogenic nature). * **D. Spectroscopy:** This is a **confirmatory test** used to detect the presence of blood by identifying specific absorption bands of hemoglobin derivatives (like hemochromogen). It confirms *that* a substance is blood but does not determine the *species*. **High-Yield Pearls for NEET-PG:** * **Sequence of Blood Exam:** 1. Preliminary/Screening (Benzidine, Kastle-Meyer) → 2. Confirmatory (Teichmann/Takayama crystals, Spectroscopy) → 3. Species Origin (Precipitin, Electrophoresis) → 4. Individualization (DNA profiling). * **Takayama Test:** Also known as the Haemochromogen crystal test; it is the most reliable confirmatory test for blood. * **Species Identification:** Apart from the Precipitin test, **Coombs’ Antiglobulin Consumption Test** and **Gel Diffusion** are also used.

Question 39: Which among the following is not a cause of suspended animation?

A. Cholera
B. Sunstroke
C. Electrocution
D. Severe brain stem injury (Correct Answer)

Explanation: **Explanation:** **Suspended Animation** (also known as Apparent Death) is a clinical state where the vital functions (respiration and circulation) are at such a low level that they cannot be detected by routine clinical examination. If timely resuscitation is provided, the person can be revived. **Why "Severe brain stem injury" is the correct answer:** Suspended animation is, by definition, a **reversible** state. A severe brain stem injury involves structural damage to the vital centers (medulla oblongata) responsible for cardiac and respiratory function. Such damage is typically irreversible and leads to brain death or somatic death rather than a temporary suspension of detectable signs. Therefore, it is a cause of death, not suspended animation. **Analysis of Incorrect Options:** * **Cholera:** Severe dehydration and electrolyte imbalance can lead to profound shock and a "death-like" state where the pulse is imperceptible. * **Sunstroke:** Hyperpyrexia can lead to a state of unconsciousness and metabolic collapse where vital signs become extremely faint. * **Electrocution:** Electric shock often causes temporary respiratory paralysis or ventricular fibrillation that may mimic death but can be reversed with immediate CPR or defibrillation. **High-Yield Clinical Pearls for NEET-PG:** * **Common Causes of Suspended Animation:** Remember the mnemonic **"A-B-C-D-E"**: **A**nesthesia, **B**arbiturate poisoning, **C**holera/Cold (Hypothermia), **D**rowning/Dormant (Newborns), **E**lectrocution/Electricity. * **Duration:** It can last from a few seconds to several minutes (rarely hours in profound hypothermia). * **Medico-legal Importance:** It is crucial to confirm death using an ECG or ultrasound to avoid premature embalming or autopsy. * **Voluntary Suspended Animation:** Some practitioners of Yoga are reported to achieve this state through deep meditative trances.

Question 40: What information can be obtained from the entomology of a cadaver?

A. Time since death (Correct Answer)
B. Mode of death
C. Manner of death
D. Identification of a disease

Explanation: ### Explanation **Correct Answer: A. Time since death** **Forensic Entomology** is the study of insects and other arthropods associated with a cadaver to assist in legal investigations. Its primary application in forensic medicine is the estimation of the **Post-Mortem Interval (PMI)** or time since death. This is achieved through two main methods: 1. **Succession Pattern:** Different species of insects (e.g., Blowflies, Flesh flies, Beetles) arrive at the body in a predictable, chronological wave-like pattern based on the stage of decomposition. 2. **Life Cycle Analysis:** By studying the developmental stages (egg → larva → pupa → adult) of the oldest insects present on the body and correlating them with environmental temperatures, experts can calculate the minimum time elapsed since death. **Why other options are incorrect:** * **B & C (Mode and Manner of Death):** While insects may occasionally concentrate around perimortem wounds (indicating the site of trauma), they do not provide definitive evidence regarding the *mode* (biochemical/physiological failure) or *manner* (homicidal, suicidal, accidental) of death. * **D (Identification of a Disease):** Entomology is not used to diagnose underlying natural diseases. However, a related field called **Entomotoxicology** can identify toxins or drugs in the larvae if the body is too decomposed for standard toxicology. **NEET-PG High-Yield Pearls:** * **First Responders:** Blowflies (*Calliphoridae*) are usually the first to arrive, often within minutes of death. * **Casper’s Dictum:** Relates to the rate of putrefaction (1 week in air = 2 weeks in water = 8 weeks in earth); insects significantly accelerate this process in air. * **Specimen Collection:** For accurate PMI, forensic experts must collect the **largest (oldest) larvae** and preserve some alive to hatch for species identification.

Practice by Chapter

Personal Identification Methods

Practice Questions

Anthropometry

Practice Questions

Dactylography (Fingerprinting)

Practice Questions

Dental Identification

Practice Questions

DNA Profiling

Practice Questions

Facial Reconstruction

Practice Questions

Superimposition Techniques

Practice Questions

Hair and Fiber Analysis

Practice Questions

Handwriting Analysis

Practice Questions

Identification of Remains

Practice Questions

Mass Disaster Victim Identification

Practice Questions

Age, Sex and Race Determination

Practice Questions

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