Special Autopsy Techniques — MCQs
What substance is measured in the vitreous humor to estimate the time since death?
The medicolegal importance of postmortem lividity is all except:
Most accurate method to determine time since death in early post-mortem period?
Virchow's method of organ removal is:
In a patient suspected to have Rabies, a corneal smear sample was taken. Which of the following is the MOST SENSITIVE investigation for this specimen?
Method of autopsy in which organs of various systems are removed en masse:
Incisions for medicolegal autopsy include all except?
For autopsy, vitreous is preserved in:
A woman died within 5 years of marriage under suspicious circumstances. Her parents complained that her in-laws used to frequently demand dowry. Under which of the following sections can a magistrate authorize an autopsy of the case?
Autopsy finding after 24 hours in a case of death due to myocardial infarction is
Special Autopsy Techniques Indian Medical PG Practice Questions and MCQs
Question 1: What substance is measured in the vitreous humor to estimate the time since death?
- A. Sodium
- B. Potassium (Correct Answer)
- C. Proteins
- D. Chloride
Explanation: ***Potassium*** - **Potassium** concentration in the vitreous humor increases predictably after death due to the breakdown of cellular membranes and passive diffusion from cells. - This consistent post-mortem rise makes it a reliable marker for estimating the **post-mortem interval** (PMI) or time since death. *Sodium* - While sodium is present in the vitreous humor, its post-mortem changes are not as consistent or predictable as potassium for estimating the **time since death**. - Sodium levels tend to decrease slightly after death, but this decline is influenced by various factors and is less reliable for **PMI determination**. *Proteins* - **Proteins** are generally stable in the vitreous humor for some time post-mortem, but their levels do not show a consistent or predictable change that can be used to accurately estimate the **time since death**. - Measuring protein levels is more useful in assessing specific eye pathologies rather than **PMI**. *Chloride* - **Chloride** concentrations in the vitreous humor exhibit post-mortem changes, but like sodium, they are not as precise or reliable as potassium for estimating the **post-mortem interval**. - Its diffusion out of the vitreous humor can be more variable and less consistently linear than potassium's influx.
Question 2: The medicolegal importance of postmortem lividity is all except:
- A. Determination of body movement after death
- B. Position of the body at death
- C. Identity of the deceased (Correct Answer)
- D. Time since death
Explanation: ***Identity of the deceased*** - **Postmortem lividity** (livor mortis) results from gravitational pooling of blood in dependent body parts after death and provides important medicolegal information. - However, lividity does **not help in identifying the deceased person**. Identity is established through other means such as physical features, fingerprints, dental records, DNA analysis, or personal belongings. - While lividity patterns can provide investigative clues, they have **no role in determining who the deceased person is**. *Determination of body movement after death* - **Fixed lividity** (occurring after 8-12 hours) indicates the body remained in the same position. If lividity appears in areas that should have been elevated, this suggests the **body was moved after lividity developed**. - This is crucial medicolegal evidence in criminal investigations to determine if a body was **relocated or manipulated** after death. *Position of the body at death* - The **distribution of livor mortis** corresponds to dependent body parts. Lividity on the back indicates supine position, while lividity on the anterior surface suggests prone position. - This helps forensic pathologists **reconstruct the position** of the body at or shortly after death, which is important for crime scene analysis. *Time since death* - Lividity typically **appears within 30 minutes to 2 hours** after death and becomes **fixed after 8-12 hours**. - The **onset, progression, and fixation** of lividity, combined with other postmortem changes, help estimate the **postmortem interval**, though environmental factors can affect accuracy.
Question 3: Most accurate method to determine time since death in early post-mortem period?
- A. Algor mortis
- B. Livor mortis
- C. Rigor mortis
- D. Potassium in vitreous humor (Correct Answer)
Explanation: **Potassium in vitreous humor** - **Potassium concentration in the vitreous humor** increases at a relatively consistent rate after death, making it one of the most reliable methods for estimating time since death, particularly in the **early post-mortem period**. - The vitreous humor is an isolated compartment, less affected by environmental factors compared to other body parts, leading to more **predictable and stable changes**. *Algor mortis* - Refers to the **cooling of the body** after death, which is highly influenced by environmental factors such as ambient temperature, clothing, and body size. - Its accuracy diminishes rapidly, especially after the first few hours, due to these variable influencing factors. *Livor mortis* - Involves the **gravitational settling of blood** in capillaries, leading to discoloration of the skin. - While it helps determine body position at death and whether the body has been moved, its onset (30 minutes to 2 hours) and fixation (8-12 hours) are too broad for precise time estimation in the early post-mortem period. *Rigor mortis* - Describes the **stiffening of muscles** due to the depletion of adenosine triphosphate (ATP) after death. - Its onset (2-6 hours), progression, and resolution (24-84 hours) are highly variable and affected by factors such as muscle activity before death, temperature, and body build, making it less accurate for precise early time estimation.
Question 4: Virchow's method of organ removal is:
- A. In situ removal
- B. Organs removed one by one (Correct Answer)
- C. Minimal invasive autopsy
- D. Organs removed en masse
Explanation: ***Organs removed one by one*** - Virchow's method involves the **removal and examination of each organ individually**, allowing for detailed assessment of isolated pathologies. - This systematic approach helps in identifying specific organ lesions and pathologies without damage to other organs, as is the case when they are removed in groups or en masse. *In situ removal* - This method implies that organs are **examined within the body cavity** without being fully extracted. - While some initial observations can be made in situ, a thorough examination as required by Virchow's method necessitates the complete removal of each organ. *Minimal invasive autopsy* - **Minimally invasive autopsies** involve techniques like imaging (CT, MRI) and biopsies, aiming for less disruption to the body. - This approach fundamentally differs from Virchow's traditional technique which involves a **full dissection and individual organ removal**. *Organs removed en masse* - The **en masse removal technique** (e.g., Ghon or Letulle methods) involves extracting blocks of organs connected by anatomical relationships. - This contrasts with Virchow's method, which emphasizes **individual organ removal** to avoid obscuring localized findings.
Question 5: In a patient suspected to have Rabies, a corneal smear sample was taken. Which of the following is the MOST SENSITIVE investigation for this specimen?
- A. Virus isolation
- B. Immunofluorescence test
- C. Negri body visualization
- D. RT PCR (Correct Answer)
Explanation: ***RT PCR*** - **Reverse transcriptase polymerase chain reaction (RT-PCR)** is the **most sensitive molecular method** for detecting **rabies virus RNA** in corneal smear samples. - It provides **rapid, highly sensitive, and specific** detection of rabies viral nucleic acid, making it the preferred method for antemortem diagnosis from this specimen. - RT-PCR has **higher sensitivity than immunofluorescence** for corneal samples. *Immunofluorescence test* - **Direct fluorescent antibody (DFA) test** can be performed on corneal impression smears and is an established antemortem diagnostic method. - However, its **sensitivity is lower than RT-PCR** for this specific sample type, with higher false-negative rates. - DFA remains the gold standard primarily for **post-mortem brain tissue examination**. *Virus isolation* - Virus isolation is **time-consuming, less sensitive**, and requires specialized biosafety level 3 facilities. - **Corneal smears** have lower viral loads, making isolation less reliable compared to molecular methods. - Not routinely used for rapid diagnosis. *Negri body visualization* - **Negri bodies** are pathognomonic cytoplasmic inclusion bodies found in neurons, particularly in the **hippocampus and cerebellum**. - These can **only be visualized in brain tissue** through histopathological examination (post-mortem). - **Cannot be detected in corneal smears** as they are neuronal inclusions.
Question 6: Method of autopsy in which organs of various systems are removed en masse:
- A. Lettulle (Correct Answer)
- B. Virchow
- C. Rokitansky
- D. Ghon
Explanation: ***Lettulle*** - The **Lettulle method** (or en masse method) involves the removal of organs in large blocks or as a single unit, which helps preserve anatomical relationships. - This technique is particularly useful for studying the **interrelationships between organs** and the spread of disease involving multiple systems. *Virchow* - The **Virchow method** involves the individual removal of each organ, which allows for detailed examination of each organ separately. - This method is straightforward but can disrupt the **anatomical relationships** between organs. *Rokitansky* - The **Rokitansky method** involves *in situ* dissection of organs, with the organs remaining largely in the body during dissection. - This technique is valued for maintaining the **topographical integrity** of organ systems within the body cavity. *Ghon* - The **Ghon method** is a modified block dissection method, focusing on the removal of specific organ blocks. - This often includes the **thoracic and abdominal organs** together, maintaining their anatomical connections.
Question 7: Incisions for medicolegal autopsy include all except?
- A. 'Y' shaped
- B. Modified 'Y' shaped
- C. Modified 'I' shaped (Correct Answer)
- D. 'T' shaped
Explanation: **Modified 'I' shaped** - The **modified 'I' shaped** incision is not a standard or recognized incision for a medicolegal autopsy. - Standard autopsy incisions are designed to provide comprehensive access while maintaining anatomical integrity as much as possible for future viewing or reconstruction. *'Y' shaped* - The **'Y' shaped incision** is a commonly used incision in medicolegal autopsies, starting at the shoulders and meeting at the xiphoid process, then extending to the pubic symphysis. - This incision allows for optimal exposure of the neck, chest, and abdominal organs. *Modified 'Y' shaped* - The **modified 'Y' shaped incision** is a variation of the standard 'Y' incision, often used to avoid cutting through prominent scars or to provide better access in specific cases. - It maintains the general principle of broad exposure while adapting to individual circumstances. *'T' shaped* - The **'T' shaped incision** is another recognized incision, though less common than the 'Y' shape, primarily used for better exposure of the neck and chest in certain circumstances. - It involves a horizontal incision across the upper chest, intersecting with a vertical midline incision.
Question 8: For autopsy, vitreous is preserved in:
- A. Phenol
- B. Fluoride (Correct Answer)
- C. Sulphuric acid
- D. Xylol
Explanation: ***Fluoride (Sodium fluoride)*** - **Sodium fluoride** is the preferred preservative for vitreous humor samples collected during autopsy, especially when testing for **alcohol** and **glucose** levels. - It acts as an **enzyme inhibitor**, preventing post-mortem metabolism of glucose and fermentation of alcohol by microorganisms, thus maintaining the sample's integrity. *Phenol* - **Phenol** is an antiseptic and disinfectant often used in tissue preservation for histological examination, but it is not typically used for vitreous humor to preserve metabolites like glucose or alcohol. - It can interfere with some analytical methods used for vitreous analysis. *Sulphuric acid* - **Sulphuric acid** is a strong acid that would cause significant denaturation of proteins and alteration of the chemical composition of vitreous humor. - It is not suitable for preserving biological samples for most analyses, especially for fragile metabolites such as glucose. *Xylol* - **Xylol** (xylene) is a common solvent used in histology for clearing tissues (removing alcohol) before paraffin embedding, making it unsuitable for direct preservation of body fluids like vitreous humor. - It would dissolve cellular components and denature proteins, rendering the sample useless for chemical analysis.
Question 9: A woman died within 5 years of marriage under suspicious circumstances. Her parents complained that her in-laws used to frequently demand dowry. Under which of the following sections can a magistrate authorize an autopsy of the case?
- A. Section 302 IPC
- B. Section 174 Cr Pc
- C. Section 304 IPC
- D. Section 176 Cr Pc (Correct Answer)
Explanation: ***Section 176 Cr PC*** - This section empowers a **Magistrate to hold an inquiry into the cause of death** in cases of suspicious circumstances, including deaths within seven years of marriage where dowry harassment is alleged. - The magistrate can **order a post-mortem examination** or even a second post-mortem if there are doubts about the initial findings, making it the appropriate section for **magisterial authorization** of autopsy. - In dowry death cases, Section 176 provides judicial oversight and ensures an independent inquiry beyond police investigation. *Section 174 Cr PC* - This section deals with **police inquiry** and report on suicide and suspicious deaths, empowering the **police officer** (not magistrate) to investigate and order an autopsy. - While Section 174 is used for initial police investigation in suspicious deaths, the question specifically asks about **magistrate authorization**, which falls under Section 176. - Section 174 is the procedural provision for police-initiated investigation, whereas magisterial inquiry requires Section 176. *Section 304 IPC* - This section pertains to **punishment for culpable homicide not amounting to murder**. It is a substantive penal provision, not a procedural law. - It deals with the legal consequence of an act after investigation and trial, not with the investigative procedure for conducting an autopsy. - Charges under Section 304 IPC may result from findings after the autopsy, but it doesn't authorize the autopsy itself. *Section 302 IPC* - This section specifies the **punishment for murder**. Like Section 304 IPC, it is substantive criminal law defining a crime and its penalty. - It would be invoked *after* the investigation reveals evidence of murder, not during the initial phase of ordering an autopsy for a suspicious death. - An autopsy authorized under Cr PC sections might lead to charges under Section 302 IPC, but it doesn't authorize the autopsy procedure.
Question 10: Autopsy finding after 24 hours in a case of death due to myocardial infarction is
- A. Coagulative necrosis. (Correct Answer)
- B. Fat necrosis.
- C. Liquefactive necrosis.
- D. Caseous necrosis.
Explanation: ***Coagulative necrosis*** - Coagulative necrosis is the predominant histological finding after **myocardial infarction**, typically occurring within the first 12 hours [1]. - It results in preserved tissue architecture with **cellular outlines** remaining visible, indicating ischemic tissue damage [1,2]. *Liquefactive necrosis* - Commonly associated with **bacterial infections** or brain infarction, it leads to the transformation of tissue into liquid pus, which is not characteristic of myocardial infarction. - It occurs later and is not typically observed in heart tissue within 12 hours post-infarction. *Fat necrosis* - Primarily occurs due to damage to **adipose tissue**, as seen in cases of pancreatitis or trauma, and is not relevant to myocardial injury. - It is characterized by the release of **lipases** and fatty acids, a response not seen in myocardial infarction. *Caseous necrosis* - Often associated with **tuberculosis** or fungal infections, presenting as cheese-like necrotic tissue, it is not a feature of myocardial infarction. - This type of necrosis appears much later and reflects chronic granulomatous inflammation rather than acute ischemic damage. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, p. 552. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Heart, pp. 552-554.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free