Identification — MCQs

Identification Indian Medical PG Practice Questions and MCQs

Question 131: All are tests done on blood except?

A. Acid phosphatase test (Correct Answer)
B. Benzidine test
C. Hemochromogen test
D. Teichmann's test

Explanation: ### Explanation The correct answer is **A. Acid phosphatase test**, as this is a screening test used for the identification of **semen**, not blood. #### 1. Why Acid Phosphatase Test is the Correct Answer The Acid Phosphatase (AP) test (also known as the Walker test) detects high levels of the enzyme acid phosphatase secreted by the prostate gland. It is a presumptive test for seminal stains. In forensic practice, a positive AP test suggests the presence of semen, which is then confirmed by identifying spermatozoa or using the Prostate-Specific Antigen (PSA/p30) test. #### 2. Analysis of Other Options (Tests for Blood) * **Benzidine Test (Option B):** This is a highly sensitive **presumptive (screening) test** for blood. It relies on the peroxidase-like activity of hemoglobin, which reacts with hydrogen peroxide to produce a blue color. Due to the carcinogenicity of benzidine, it is often replaced by the Phenolphthalein (Kastle-Meyer) test. * **Hemochromogen Test (Option C):** Also known as the **Takayama test**, this is a **confirmatory test** for blood. It involves heating the sample with Takayama reagent to produce characteristic salmon-pink, feathery crystals of pyridine hemochromogen. * **Teichmann’s Test (Option D):** This is another **confirmatory test** for blood. It involves heating blood with glacial acetic acid and salt to produce dark brown, rhombic crystals of **hemin (hematin hydrochloride)**. #### 3. High-Yield Clinical Pearls for NEET-PG * **Presumptive Tests for Blood:** Benzidine (Blue), Phenolphthalein (Pink), Luminol (Chemiluminescence), and Ortho-tolidine. * **Confirmatory Tests for Blood:** Teichmann test (Hemin crystals) and Takayama test (Hemochromogen crystals). * **Species Identification:** Once a stain is confirmed as blood, the **Precipitin test** is used to determine if it is of human origin. * **Semen Identification:** AP test (Screening), Barberio’s test (Spermine crystals), Florence test (Choline crystals), and LDH-X isoenzyme.

Question 132: What is the most effective method for personal identification?

A. Photography
B. Dactylography (Correct Answer)
C. Anthropometry
D. X-ray determination

Explanation: **Explanation:** **Dactylography** (Fingerprinting or the Galton System) is considered the most effective and reliable method for personal identification. This is based on two fundamental principles: **Permanence** (the ridge patterns are formed by the 4th month of intrauterine life and remain unchanged until death/decomposition) and **Uniqueness** (no two individuals, including monozygotic twins, have identical fingerprints). The mathematical probability of two people having the same fingerprints is 1 in 64 billion, making it virtually infallible. **Analysis of Incorrect Options:** * **Photography (A):** While useful for general recognition, it is unreliable due to aging, surgical alterations, or changes in facial hair and weight. * **Anthropometry (C):** Also known as the Bertillon system, it relies on body measurements. It was discarded because measurements change with age and different individuals can share similar dimensions (as famously proven in the Will West case). * **X-ray determination (D):** Useful for identifying skeletal remains or age estimation, but it requires antemortem records for comparison and is not as universally unique or easily categorized as fingerprints. **High-Yield Clinical Pearls for NEET-PG:** * **Poroscopy:** The study of sweat gland pores on the ridges (Locard’s method); useful when only a fragment of a fingerprint is available. * **Dactylography in Twins:** Fingerprints are different even in identical (monozygotic) twins, whereas DNA profiles are the same. * **Permanent Impairment:** Fingerprints can only be altered by deep injuries involving the dermis (e.g., leprosy, electric burns, or radiation). * **Primary Patterns:** Loops (65% - most common), Whorls (25%), Arches (7%), and Composite (2-3%).

Question 133: What percentage of total height does the tibia contribute?

A. 10% of height
B. 20% of height (Correct Answer)
C. 30% of height
D. 40% of height

Explanation: ### Explanation **Correct Answer: B. 20% of height** In forensic anthropology and identification, the stature of an individual can be estimated from the measurements of long bones using various formulas (e.g., **Karl Pearson’s formula** or **Trotter and Gleser’s formula**). As a general rule of thumb used in forensic medicine: * **The Tibia** contributes approximately **20% (1/5th)** of the total body height. * **The Femur** contributes approximately **25% (1/4th)** of the total body height. **Analysis of Options:** * **Option A (10%):** This is too low for any major long bone. Small bones like the clavicle or the length of the foot are closer to this proportion, but not the weight-bearing bones of the lower limb. * **Option C (30%):** This overestimates the tibia's contribution. While the entire lower limb (thigh + leg) accounts for nearly 45-50% of height, the tibia alone does not exceed 20-22%. * **Option D (40%):** This is incorrect. Even the femur, the longest bone in the body, only accounts for about 25% of the total stature. **High-Yield Clinical Pearls for NEET-PG:** 1. **Femur** is the most accurate bone for stature estimation, followed by the **Tibia**. 2. **Pan’s Rule:** A quick bedside rule where the length of the humerus is roughly 1/5th to 1/6th of the total height. 3. **Symphysis Pubis to Heel:** In a well-proportioned adult, the distance from the symphysis pubis to the heel is exactly half (50%) of the total height. 4. **Arm Span:** In adults, the total arm span (fingertip to fingertip) is roughly equal to the total height. 5. **Multiplication Factors:** For a quick estimate, the height is roughly **4.5 to 5 times** the length of the femur and **5 times** the length of the tibia.

Question 134: Which fingerprint pattern shows two or more deltas?

A. Loop
B. Plain arch
C. Tented arch
D. Whorls (Correct Answer)

Explanation: **Explanation:** Fingerprint identification (Dactylography) is based on the arrangement of ridges and furrows. The classification depends on the presence of **deltas** (triangular points where three ridge lines meet) and **cores** (the center of the pattern). **1. Why Whorls are correct:** A **Whorl** is characterized by ridges that make at least one complete circuit (circular, spiral, or almond-shaped). By definition, a whorl pattern must have **two or more deltas**. This complexity makes whorls a distinct category in the Galton-Henry system of classification. **2. Why other options are incorrect:** * **Loop (Option A):** This is the most common pattern (60-70%). It contains only **one delta**. Ridges enter from one side, curve back, and exit from the same side. * **Plain Arch (Option B):** This is the simplest pattern. Ridges flow from one side to the other with a slight rise. It has **no delta** and no core. * **Tented Arch (Option C):** A variation of the arch where ridges rise sharply in the center (like a tent pole). While more angular than a plain arch, it still typically possesses **no true delta**. **High-Yield Clinical Pearls for NEET-PG:** * **Frequency:** Loops (60-70%) > Whorls (25-30%) > Arches (5-7%). * **Permanence:** Fingerprints are formed at the **4th month of intrauterine life** and remain unchanged until death (and even after, until the skin decomposes). * **Dactylography (Galton-Henry System):** It is the most reliable method of identification (error rate is 1 in 64 billion). * **Poroscopy (Locard’s Method):** Study of sweat gland pores on the ridges; useful when only partial prints are available. * **Adermatoglyphia:** A rare genetic condition where individuals are born without fingerprints (associated with SMARCAD1 gene mutation).

Question 135: What is the legal age by which a fetus is considered capable of independent existence?

A. 240 days
B. 230 days
C. 220 days
D. 210 days (Correct Answer)

Explanation: **Explanation:** The question pertains to the concept of **Viability**, which is the period of intrauterine life after which the fetus is considered capable of maintaining an independent existence outside the mother's womb. **1. Why 210 days is correct:** In Forensic Medicine and Obstetrics, a fetus is traditionally considered viable at the end of **7 lunar months** (7 × 30 days = **210 days**). At this stage, the fetus typically weighs approximately 1.1 kg and measures about 35 cm. This is the legal threshold often cited in Indian jurisprudence and classical textbooks (like Reddy’s) for the minimum age of independent existence, although modern neonatal care has pushed biological viability earlier. **2. Analysis of Incorrect Options:** * **220, 230, and 240 days:** These represent later stages of gestation (approx. 31–34 weeks). While a fetus at these ages is significantly more mature and has a higher survival rate, they do not represent the *minimum* legal threshold for the onset of viability. **3. High-Yield Facts for NEET-PG:** * **Hase’s Rule:** Used to determine the age of the fetus. For the first 5 months, the age in months is the square root of the length (cm). For the last 5 months, the length (cm) divided by 5 gives the age in months. * **Appearance of Ossification Centers:** * **Calcaneum:** 5th month (210 days). * **Talus:** 7th month (210 days). * **Lower end of Femur:** 9th month (36-40 weeks) – crucial for proving full-term status. * **MTP Act (India):** Note that the Medical Termination of Pregnancy (Amendment) Act, 2021, allows termination up to **24 weeks** (168 days) for specific categories of women, which is a separate legal milestone from the classical 210-day viability rule.

Question 136: Robert's sign is a feature of which of the following?

A. Le fort fracture grade II
B. Dead born infant (Correct Answer)
C. Live born infant
D. Orbital fracture

Explanation: **Explanation:** **Robert’s Sign** is a classic radiological feature used to diagnose **intrauterine fetal death (IUFD)**. It refers to the presence of **gas shadows** (usually nitrogen) within the fetal heart and large blood vessels (aorta and vena cava). This occurs due to the decomposition of blood following fetal demise and can be seen on an X-ray as early as 12 hours after death. **Why the correct answer is right:** * **Option B (Dead born infant):** Robert’s sign is a definitive sign of fetal death in utero. Along with Spalding’s sign (overlapping of skull bones), it confirms that the fetus is no longer alive before delivery. **Why the incorrect options are wrong:** * **Option A & D (Le Fort and Orbital fractures):** These are traumatic injuries of the facial skeleton. While they involve specific radiological signs (e.g., "Dish-face deformity" in Le Fort II), they have no association with fetal gas formation. * **Option C (Live born infant):** A live-born infant will have clear lung expansion (revealed by the hydrostatic test) and no intravascular gas shadows, as decomposition has not occurred. **High-Yield Clinical Pearls for NEET-PG:** * **Spalding’s Sign:** Overlapping of fetal skull bones due to liquefaction of the brain (appears 4–7 days after death). * **Deuel’s Halo Sign:** Edema of the fetal scalp causing a "halo" appearance on X-ray (indicates fetal death). * **Hydrostatic Test (Raygat’s Test):** Used to differentiate between a stillborn and a live-born infant by checking if the lungs float in water (positive in live-born). * **Wredin’s Test:** Presence of air in the middle ear, indicating the infant breathed after birth.

Question 137: Gustafson's method is useful for the determination of which of the following?

A. Age (Correct Answer)
B. Stature
C. Race
D. Sex

Explanation: **Explanation:** **Gustafson’s Method** is a forensic technique used for **Age Estimation** in adults by examining morphological changes in a single-rooted tooth. As a person ages, teeth undergo physiological and pathological alterations. Gustafson identified six specific parameters, often remembered by the mnemonic **"PARTS-S"**: 1. **P**eriodontosis (Gum recession) 2. **A**ttrition (Wearing down of occlusal surfaces) 3. **R**oot Resorption 4. **T**ranslucency of Dentin (The most reliable single factor) 5. **S**econdary Dentin deposition (Reduces pulp cavity size) 6. **S**ementum (Cementum) Apposition at the root Each parameter is scored from 0 to 3, and the total score is applied to a regression formula to estimate age with an error margin of approximately ±5–10 years. **Analysis of Incorrect Options:** * **B. Stature:** Estimated using long bones (e.g., Femur, Humerus) via **Pearson’s or Trotter & Gleser formulae**. * **C. Race:** Determined by skull features (Cephalic Index) or dental traits like the **Carabelli cusp** (common in Caucasoids) and shovel-shaped incisors (Mongoloids). * **D. Sex:** Determined by pelvic morphology (most accurate) or skull features. In dentistry, **Amelogenin protein** analysis or Barr bodies in pulp are used for sexing. **High-Yield Clinical Pearls for NEET-PG:** * **Boyde’s Method:** Uses incremental lines in enamel (Cross-striations) for age estimation in children. * **Stack’s Method:** Uses the weight and height of dental tissues for age estimation in fetuses/infants. * **Miles’ Method:** Estimates age based on the degree of molar wear. * **Translucency of Dentin** is considered the most consistent and reliable parameter in Gustafson’s method for aging.

Question 138: An unidentified dead body is brought for autopsy. A faded tattoo mark is noticed on the left arm. Which of the following methods can be used to enhance the tattoo mark for identification?

A. Application of isopropyl alcohol
B. Infrared photography (Correct Answer)
C. Bright illumination
D. All of the above

Explanation: **Explanation:** **Identification via tattoo marks** is a vital aspect of forensic investigation, as tattoos are often permanent and unique to an individual. When a tattoo becomes faded due to decomposition, scarring, or deliberate attempts at removal, specialized techniques are required to visualize the underlying pigment. **Why Infrared (IR) Photography is the Correct Answer:** Tattoo pigments, particularly those containing carbon or metallic salts, are deposited in the dermis. Even if the epidermis is damaged or the mark is faded to the naked eye, these pigments absorb infrared light differently than the surrounding tissue. **Infrared photography** can penetrate the superficial layers of the skin and capture the contrast of the deep-seated pigment, making the "invisible" or faded mark clearly legible on the photograph. **Analysis of Incorrect Options:** * **A. Application of isopropyl alcohol:** While alcohol is used for cleaning the skin, it has no optical properties that enhance deep-seated dermal pigments. In some cases, applying glycerin or paraffin may slightly improve transparency, but alcohol is not a standard enhancement method. * **C. Bright illumination:** Standard white light (visible spectrum) often causes glare or reflects off the surface of decomposing skin, which can further obscure a faded mark rather than revealing it. **High-Yield Clinical Pearls for NEET-PG:** * **Tattoo Pigment Location:** Tattoos are permanent because the ink is injected into the **dermis** (specifically captured by dermal fibroblasts and macrophages). * **Removal:** The most common method for professional tattoo removal is the **Q-switched Laser**. * **Forensic Significance:** Tattoos can indicate a person's religion, profession, or gang affiliation. * **Other Visualization Techniques:** If the body is highly decomposed, the skin can be peeled off and viewed against a strong light source (transillumination) or treated with **hydrogen peroxide** to clear the tissue.

Question 139: All are true about permanent teeth, except?

A. A ridge is present between the neck and body. (Correct Answer)
B. Anterior teeth are inclined forward.
C. Roots of molars are larger.
D. They are ivory white in color.

Explanation: In forensic odontology, distinguishing between deciduous (milk) and permanent teeth is a high-yield topic for NEET-PG. ### **Explanation of the Correct Option** **Option A (A ridge is present between the neck and body)** is the correct answer because this feature is characteristic of **deciduous teeth**, not permanent teeth. In deciduous teeth, there is a prominent bulging ridge of enamel at the cervical margin (where the crown meets the neck), making the junction appear constricted. Permanent teeth lack this prominent cervical ridge, having a smoother transition from the crown to the root. ### **Analysis of Incorrect Options** * **Option B (Anterior teeth are inclined forward):** In the permanent dentition, the incisors and canines are naturally inclined slightly labially (forward). In contrast, deciduous anterior teeth are positioned more vertically. * **Option C (Roots of molars are larger):** Permanent molars have longer, sturdier, and more robust roots to support the increased forces of mastication in adults. Deciduous molar roots are smaller and more divergent (flared) to accommodate the developing permanent tooth buds underneath. * **Option D (They are ivory white in color):** Permanent teeth have thicker dentin, giving them an **ivory-white or yellowish-white** appearance. Deciduous teeth have thinner enamel and dentin, appearing **chalky-white or bluish-white**. ### **High-Yield Clinical Pearls for NEET-PG** * **First tooth to erupt:** Lower central incisor (6–8 months). * **First permanent tooth to erupt:** First Molar (6 years), often called the "6-year molar." * **Gustafson’s Method:** The most reliable method for age estimation using a single tooth (evaluates 6 parameters: Attrition, Periodontitis, Secondary dentin, Cementum apposition, Root resorption, and Transparency). * **Total Number:** Deciduous = 20; Permanent = 32. * **Mixed Dentition Period:** Usually occurs between ages 6 and 12.

Question 140: Which method is most specific and sensitive for identification?

A. Anthropometry
B. Dactylography (Correct Answer)
C. Skull
D. Pelvis

Explanation: **Explanation:** **Dactylography (Fingerprinting)** is considered the most specific and sensitive method for identification because of two fundamental principles: **uniqueness** and **permanence**. No two individuals, including monozygotic twins, have identical fingerprints. These patterns (Galton ridges) develop by the 4th month of intrauterine life and remain unchanged until death (and even after, until the skin decomposes). Its high sensitivity stems from the fact that even a partial print can be sufficient for a positive match. **Analysis of Incorrect Options:** * **Anthropometry (Bertillonage):** This system relies on physical measurements of various body parts. It was discarded because measurements change with age, and two individuals can coincidentally have similar dimensions. It is far less specific than dactylography. * **Skull & Pelvis:** These are skeletal remains used primarily for determining **biological profile** (age, sex, and stature). While the pelvis is the most reliable bone for sex determination, it cannot provide the individualistic identification that a fingerprint offers. **Clinical Pearls for NEET-PG:** * **Galton’s System:** Another name for Dactylography. * **Poroscopy (Locard’s Method):** The study of the number, size, and distribution of sweat pores on the ridges; it is even more specific than dactylography and useful when only a fragment of a print is available. * **Dactylography in Twins:** While DNA is identical in monozygotic twins, their fingerprints are **different**. * **Permanent Impairment:** Fingerprints can only be altered by deep injuries reaching the dermis, or by conditions like leprosy and certain skin diseases.

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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