Forensic Medicine 2

Arborescent (tree-like) markings, also known as Lichtenberg figures, are a unique pattern of skin burns caused by lightning. This pattern is a distinctive sign of a lightning strike and is thought to be caused by the rupture of capillaries near the skin‘s surface from the massive electrical discharge. They are not true burns and are usually transient, disappearing within a few hours to a day.

“La facies sympathique” (the sympathetic face) is a rare medico-legal sign observed in some cases of death by hanging. It refers to a unique finding where there is unilateral miosis (constriction of the pupil) and ptosis (drooping of the eyelid) on the side of the face opposite to the ligature knot. This is thought to be caused by pressure from the ligature on the cervical sympathetic nerve, which leads to a localized disruption of the sympathetic nervous supply to the eye. The resulting facial appearance is named “sympathetic” because it resembles the face of a person who has undergone a surgical sympathectomy.

True Vesication (blisters caused by burns in a living person):

Occurs before death (antemortem).

The vesicles contain a protein-rich fluid (exudate) that is a result of the body‘s inflammatory response.

There is an inflammatory zone present at the base of the blister, showing a vital reaction.

False Vesication (postmortem blisters):

Occurs after death.

The vesicles contain gas (not fluid) from decomposition.

There is no inflammatory or respiratory zone because the body‘s vital functions have ceased.

Because all the options describe a genuine difference between the two conditions, “None of the above” is the correct choice.

Tentative cuts are superficial, non-lethal, parallel incised wounds that often precede a deeper, fatal cut. They are almost exclusively seen in suicidal injuries, particularly in cases of wrist or neck slashing. The person tests the sharpness of the weapon or their resolve by making these “hesitation marks” before making the final, fatal wound.

“Pond fracture,” also known as a “ping-pong” fracture, is a type of depressed skull fracture. It gets its name because the soft, pliable skull bone in infants and young children can be indented inwards, much like a ping-pong ball that has been pushed with a finger. The bone “buckles” inwards without a clean break. This type of fracture is common in children, particularly neonates, because their skull bones are still soft and not fully ossified. The injury can occur as a result of birth trauma, either from the mother‘s pelvic bones or the use of forceps during delivery, or from postnatal head trauma. It is very rare in adults due to the rigid nature of their skull bones.

Section 320 of the Indian Penal Code (IPC) defines what constitutes grievous hurt. The section provides an exhaustive list of eight types of injuries that are classified as grievous, including:

Permanent privation of the sight of either eye or hearing of either ear.

Fracture or dislocation of a bone or a tooth.

Permanent disfiguration of the head or face.

Any hurt which endangers life or causes severe bodily pain for 20 days or more.

The other sections are related to different offenses:

b) 354 IPC deals with assault or criminal force to a woman with the intent to outrage her modesty.

c) 321 IPC defines “voluntarily causing hurt.” Hurt is a less severe offense than grievous hurt.

d) 402 IPC is related to property crimes and deals with assembling for the purpose of committing dacoity.

Goose skin or cutis anserina is a postmortem change seen in bodies, particularly those found in cold water. It is a persistent contraction of the erector pili muscles, which are responsible for the small bumps we see when we are cold. This physiological response, which occurs while the person is still alive, becomes fixed after death and is a characteristic sign of death by drowning in cold water.

While it‘s a useful indicator, it‘s important to note that it‘s not a definitive sign of drowning, as it can be seen in other cold-related deaths, but it is most famously associated with drowning due to the immersion of the body in water.

Traumatic asphyxia is a form of mechanical asphyxia caused by prolonged or severe compression of the chest and abdomen. This pressure prevents the chest from expanding, leading to an inability to breathe and a buildup of pressure in the superior vena cava. This is characterized by classic signs like cyanosis of the face, neck, and upper chest, and subconjunctival hemorrhages (tiny red spots in the eyes).

a) Railway accident and b) Road traffic accident: These can involve a person being crushed under a vehicle or between two objects, which is a classic cause of traumatic asphyxia.

d) Stampede in crowd: A stampede can result in people being trampled and crushed, leading to compression of the chest and traumatic asphyxia.

Accidental strangulation is a form of asphyxia caused by compression of the neck. While it is a type of mechanical asphyxia, it is a different mechanism from traumatic asphyxia, which is caused by chest and abdominal compression.

A contrecoup injury is a brain injury where the damage occurs on the side opposite the point of impact. This happens when the head is struck by a force, and the brain, which is floating in cerebrospinal fluid, recoils and strikes the opposite side of the skull. This results in a coup injury (at the site of impact) and a contrecoup injury (on the opposite side).

Why the other options are incorrect:
a) Injury is on the same side: This describes a coup injury, which is the direct brain injury at the site of the head impact.

c) Injury is all over the brain: This describes a diffuse axonal injury, which results from the shearing and rotational forces that twist and tear nerve fibers throughout the brain.

d) None of the above: Since one of the options is correct, this is incorrect.

In a case of death due to starvation, the gall bladder is typically found to be distended with thick, dark, and highly concentrated (inspissated) bile. This is because the person has not been eating, and the gall bladder, which normally releases bile in response to food intake, has been inactive. The bile that continues to be produced by the liver gets stored and concentrated in the gall bladder over a prolonged period, leading to the distended and thick consistency. The other options are incorrect as they would indicate different pathologies. An empty gallbladder would suggest recent food intake, while purulent fluid would indicate an infectious process like cholecystitis.

In freshwater drowning, the cause of death within 4-5 minutes of submersion is ventricular fibrillation, which is triggered by specific changes in the blood. The key factor is the difference in osmotic pressure between the freshwater and the blood.

Haemodilution: Freshwater, being hypotonic to blood, is rapidly absorbed into the bloodstream through the alveoli. This causes a significant increase in the total blood volume.

Overloading of the heart: The increased blood volume returns to the heart, causing the chambers to become severely overloaded, especially the left side of the heart.

Haemolysis: The hypotonic freshwater causes red blood cells to swell and burst (hemolysis). This releases a massive amount of intracellular potassium (K +) into the bloodstream.

Ventricular fibrillation: This sudden, large increase in extracellular potassium disrupts the electrical rhythm of the heart, leading to ventricular fibrillation and rapid death.

Postmortem rigidity, or rigor mortis, is the stiffening of muscles after death. It follows a predictable sequence known as Nysten‘s Law. Rigor mortis first appears in the smallest muscles that are nearest to the brain, because their smaller size means their energy reserves (ATP) are depleted more quickly.

The order of onset is typically:

Eyelids and facial muscles

Neck and jaw muscles

Upper limbs

Trunk

Lower limbs

Postmortem lividity, also known as livor mortis, is the reddish-purple discoloration of the skin that occurs after death. It is a result of blood settling in the lowest, dependent parts of the body due to gravity. The medicolegal importance of postmortem lividity lies in the information it provides about the deceased person, but it does not indicate the cause of death itself in a general sense. While the color and pattern of the lividity can provide clues about the cause of death (e.g., cherry-red lividity in carbon monoxide poisoning or intense lividity in asphyxia), it does not establish the cause of death elsewhere. It‘s a sign of blood pooling, which can occur regardless of why a person died.

Time since death: The appearance and fixation of postmortem lividity can help estimate the time of death. It typically appears within 1-2 hours after death and becomes fixed after 8-12 hours, meaning it no longer shifts when the body is moved.

Manner of death: The pattern of lividity can help investigators determine if the death was a suicide, homicide, or accident. For example, in a hanging, lividity would be found in the lower limbs.

Position of the body at death: The location of lividity indicates the position of the body after death. If a body is found on its back with lividity on the front, it suggests the body was moved after death, which is a key piece of evidence in a homicide investigation.

Fingerprint patterns are formed during fetal development and are a permanent feature of an individual. However, certain diseases and injuries that affect the deep layers of the skin (the dermal papillae) can cause permanent damage to these patterns.

Leprosy is a chronic infectious disease that can cause severe nerve damage and skin lesions. The long-term inflammation and destruction of the dermal papillae in the fingers of a person with leprosy can lead to the permanent effacement of their fingerprints.

Eczema and scabies are skin conditions that can temporarily alter fingerprints, but the damage is usually reversible. Once the condition is treated, the skin heals and the original fingerprint pattern returns.

Scalds can cause blistering and peeling, which may temporarily obscure fingerprints. However, unless the burn is severe (third-degree) and causes deep scarring that damages the dermal papillae, the fingerprint ridges will regenerate.

In forensic pathology, the normal rate of a body‘s cooling after death (algor mortis) is estimated to be approximately 1.5°F per hour under standard conditions. This is the rate at which the core body temperature drops toward the ambient temperature.

It‘s important to note that this is a general rule of thumb, and the actual rate of cooling can be affected by numerous factors, including:

Ambient temperature: A colder environment will cause the body to cool faster.

Body size and fat content: Larger bodies and bodies with more fat cool more slowly.

Clothing: Clothing acts as insulation and slows the rate of cooling.

Air movement: Wind or drafts increase the rate of heat loss.

Tache noir (French for “black spot”) is a post-mortem sign that appears as a reddish-brown to black band or spot on the sclera (the white part of the eye). It is caused by the drying and desiccation of the exposed sclera when the eyelids are not fully closed after death. The exposed tissue becomes covered in dust and dried epithelial cells, and the color change is due to the oxidation of hemoglobin. It typically begins to appear a few hours after death and is an early indicator of the post-mortem interval.

Suffocation is a form of asphyxia caused by the obstruction of air flow to the lungs. This obstruction can be internal or external.

a) Choking: An internal obstruction of the airway, usually by a foreign object or a piece of food.

b) Gagging: An obstruction of the mouth and nose by an external object, such as a cloth.

c) Smothering: An external obstruction of the mouth and nose by something soft, like a pillow or a hand.

Throttling is a form of asphyxia by strangulation, not suffocation. It involves direct compression of the neck by a hand or hands, which obstructs the flow of air and blood.

The diatom test is a forensic method used to determine if a person died from drowning. Diatoms are a type of microscopic algae with hard, silica cell walls. The principle behind the test is that if a person drowns, they will inhale water, and any diatoms in that water will be carried into the lungs and then absorbed into the bloodstream. These diatoms can then be found in distant organs like the liver, kidneys, and bone marrow.

If diatoms are found in these organs, it suggests that the person was alive and had a functioning circulation when they were in the water, as the heart would have to pump the diatoms from the lungs throughout the body.

If a body is placed in water after death, diatoms might be found in the lungs but not in other organs.

In death by hanging, the primary cause of death is typically not asphyxiation from the compression of the trachea. Instead, the pressure from the ligature on the neck causes a large amount of injury to the carotid arteries and jugular veins. This leads to a sudden and massive reduction in blood flow to the brain, which causes unconsciousness and death very quickly, usually within seconds. The compression of the carotid arteries is the main cause of the rapid loss of consciousness and the subsequent death. While the trachea is also compressed, it is often not completely occluded, and the struggle to breathe is not the primary cause of death in most cases.

Foamy liver is a finding at autopsy caused by post-mortem changes. It is a sign of putrefaction, which is the decomposition of a body by microorganisms. The microorganisms, particularly gas-forming bacteria, proliferate in the liver and produce gases that form bubbles within the liver tissue, giving it a characteristic foamy or spongy appearance.

a) Arsenic poisoning causes a variety of signs at autopsy, including gastroenteritis and a fatty liver, but not a foamy appearance due to gas.

c) Mummification is a form of decomposition in which a body dehydrates in dry conditions. This process does not involve the gas-forming bacteria that cause a foamy appearance.

d) Aconite poisoning is typically characterized by symptoms like numbness, vomiting, and cardiac arrhythmias, not a foamy liver.

Extensive bruising of the neck muscles and subcutaneous tissues (ecchymosis) is a characteristic finding in death by throttling. Throttling involves the manual compression of the neck by a hand or hands, which causes significant local injury to the deep structures of the neck, including the muscles, blood vessels, and soft tissues. This manual compression crushes the tissues and ruptures small blood vessels, leading to extensive bruising.

a) Hanging: In hanging, the neck is compressed by a ligature. The injury is typically a well-demarcated furrow with limited bruising of the underlying tissues. The cause of death is often carotid artery compression rather than crushing of the neck muscles.

b) Strangulation: This is a broader term for neck compression by a force other than the person‘s own body weight. It can be caused by a ligature, a hand (throttling), or another object. While it can cause bruising, the term “throttling” specifically describes the manual compression that leads to extensive bruising.

d) Burking: This is a form of homicide that involves a combination of suffocation (smothering the mouth and nose) and compression of the chest and abdomen. It does not involve significant injury to the neck.

Dribbling of saliva is considered the most specific sign of hanging. It occurs because the pressure of the ligature on the submandibular salivary gland and the neck muscles blocks the salivary duct, leading to saliva drooling out of the corner of the mouth on the side opposite the ligature knot. Since this happens as a vital reaction while the person is still alive, it is a key indicator of antemortem hanging.

Tardieu spots: These are pinpoint hemorrhages that can be seen in the skin of the face, neck, and upper chest. They are a sign of asphyxia, but they are not specific to hanging and can be seen in other forms of asphyxial death, such as strangulation.

Ligature mark: While a ligature mark is always present in a hanging, it is not specific to antemortem hanging. A ligature mark can also be created postmortem, and its characteristics (e.g., bruising, depth) are what determine if it was formed while the person was alive.

Fracture of the thyroid cartilage: This is an important sign of death by hanging, but it is not the most specific. It is more common in hanging deaths of older individuals and can also be seen in cases of manual strangulation or throttling.

“Cafe coronary” is a forensic term used to describe a sudden death that occurs while a person is eating, due to asphyxia. It is commonly seen in individuals who are intoxicated, either by alcohol or sedatives. Intoxication impairs a person‘s chewing and swallowing reflexes, making it more likely that a large, poorly chewed piece of food will become lodged in the larynx, causing complete airway obstruction.

Aseptic autolysis, or sterile autolysis, is a post-mortem process where a body decomposes due to the action of its own enzymes without the involvement of bacteria. This occurs when the body is in a sterile environment, most commonly when a fetus dies in the uterus after the umbilical cord has been severed but before birth. The fetus is protected from bacteria by the amniotic sac, and its tissues break down due to its own cellular enzymes, a process called maceration.

Adipocere: This is a waxy substance formed from the breakdown of body fat in a moist, cool environment. It is not an aseptic process.

Putrefaction: This is the most common form of decomposition and is caused by the proliferation and action of bacteria. It is the opposite of an aseptic process.

Mummification: This is the drying and shriveling of a body in a hot, dry environment. It is caused by the rapid dehydration of tissues, which prevents bacterial growth. It is not a process of autolysis.

Death from judicial hanging is caused by a fracture and dislocation of the upper cervical vertebra, which leads to a fatal transection of the spinal cord. This is the intended and most rapid mechanism of death. This is distinct from other forms of hanging (e.g., suicidal hanging), where death is often due to asphyxia or cerebral ischemia from vascular compression.

Asphyxia and occlusion of the airway are the primary causes of death in short-drop or suicidal hanging, where death is slower and more painful.

Vasovagal shock is a possible mechanism in short-drop hangings but is not the main cause of death.

Coma is a state of unconsciousness, which would precede death but is not the ultimate cause of death.