General

Question 1

Ages of MLI and diagnosis (7th intrauterine month, 9th intrauterine months and 2 years)

Answer 1

7th intrauterine month: age of viability after which a preterm infant can live. O.C of talus

9th intrauterine months: Full term baby —> OC of upper end of tibia and lower end of femur

2 years: Legal age of end of infancy period—>Eruption of all milk teeth and OC of lower end of radius

Question 2

Age of MLI in 6, 7 and 14 years

Answer 2

6: admission to school—-> Eruption of first permanent molar

7: Age of discrimination between right and wrong—> Eruption of permanent central incisors and OC of lower end of radius

14: Age of puberty in males; below cannot commit rape—>Fusion of trochlea and capitulum

Question 3

Age of MLI in 15 years old

Answer 3

The person is tried in front of juvenile court—-> Fusion of Y-shaped suture of acetabulum

Question 4

Age of MLI 18

Answer 4

18 in females: union of head of humerus and lower ends of radius and ulna

18 in males: age of marriage, driving license and voting elections—>Union of head of femur, lower ends of tibia and fibula and distal ends of metacarpal bones and phalanges

Question 5

MLI of ages 21

Answer 5

Females: sexual consent and full civil rights—-> fusion of iliac crest and proximal end of clavicle

Males: Full civil rights—> Fusion of epiphyseal ends around the knee joint and ischial tuberosity

60 years: age of pension—> union of manubrium with body of sternum

Question 6

MLI of Finger prints

Answer 6

Finger prints is developed at the 16th weeks intrauterine and remains constant for life.

The pattern is absolutely individual even in uniovular twins.

Question 7

Finger print presence and loss (2nd part of MLI)

Answer 7

Finger prints are present in both epidermis and dermis so they could be detected after peeling of the superficial epithelium that may occur in submersion under water or putrefaction.

Permanent loss to finger prints may occur in Leprosy, amputated fingers, surgical removal, deep burns, deep corrosives or laser.

Transient loss may occur with ionizing irradiation.

Question 8

Discuss the time of eruptions of the 5 milk teeth

Answer 8

First incisor: 6 months
Second incisor: 9 months
Canine: 18 months
First molar: 12 months
Second molar: 24 months

Question 9

Enumerate time of eruption of the 8 permanent teeth

Answer 9

First incisor: 7
Second incisor: 8
Canine: 11
First molar: 9
Second molar: 10
Third molar: 6
Fourth molar: 11
Wisdom tooth: 18-25

Question 10

MLI of hair

Answer 10

1. DNA profiling, estimation of age (pubic hair at puberty) and sex/race ID
2. Identify assailant: hair of victim under nails
3. Wounds: Contusion vs laceration
4. Burns: Scald burns (wet) vs chemical or thermal burns (coma shaped)
5. Sexual offenses: pubic hair of victim may show semen and victim pubic hair may be in pubis of assailant.
6. Poising: in chronic poising of heavy metals, drug is deposited in the hair of the victim (as in napoleon)
7. Hair examination: human hairs different from animal hairs and different from fibers

Question 11

MLI of blood grouping

Answer 11

Civil cases:
1. Identification purposes.
2. Blood transfusion in emergency cases.
3. Before marriage.

Criminal cases:
1- A blood stain on the suspect’s clothes -which is similar to the victim’s blood group- is good evidence against him.
2- In cases of secretions as semen and saliva, grouping may identify the assailant (in S +ve cases).]

II- Disputed paternity:
- O father can never have AB child.
- If both parents Rh-ve, the child is never Rh+ve.
- If both parents M, the child is never N.

III- Hemolytic transfusion reaction

Question 12

Medico Legal Applications of DNA Typing

Answer 12

1. Identification or elimination of crime suspects (with the exception of identical twins, no two individuals have the same DNA).
2. Paternity/family relationship: as it is a definite positive paternity test unlike other tests which are all good negative test.

Sources of DNA In human body

3. Disaster victims’ identification
4. Identification of sex and species.
5. Identification of body remains

Question 13

Give an account on suspended animation

Answer 13

The vital functions of the body are depressed to minimum level compatible with life; to the extent that heart beats & respiratory sounds are not detected by routine methods of clinical examination.

• It may persist from few seconds to few minutes. Thus the doctor has to continue resuscitation until either the person can revive or being sure that he is clinically dead.
• The condition may be either:
• Involuntary as in cases of drowning, electric shock, after anesthesia, or in cerebral concussion, hypothermia .
• Voluntary as in cases of yoga practitioners.

Question 14

Define Persistent vegetative state

Answer 14

Persistent vegetative state describes state of the patient who loses the higher cerebral powers of the brain (state of unaware wakefulness) but the functions of the brainstem functions remain intact, (spontaneous respiration & cardiac function are not compromised).

Question 15

Causes PVS

Answer 15

traumatic (head trauma)
non- traumatic injuries (hypoxic-ischemic encephalopathy), degenerative and metabolic disorders
developmental malformations.

Question 16

PVS characteristic

Answer 16

• Wakefulness without awareness.
• Sleep and wake cycles with circadian rhythm.
• Heads and eyes can follow a moving object or move towards a loud sound.
• Unresponsive to any external stimuli.
• They may grind their teeth, smile, shed tears, grunt or moan without any apparent stimuli.

Question 17

MLI of PVS

Answer 17

The medical care team should work on

(1) prevention of infection as pneumonia, and

(2) maintenance of the patient’s clinical condition by preventing bedsores and providing balanced nutrition

Question 18

MLI of contact flattening

Answer 18

presence of contact flattening in non-dependent sites indicates alteration of the body position after death,

eg. Flattening of buttocks in hanged body indicates postmortem (PM) suspension.

Question 19

Factors affecting the cooling rate: Environmental factors

Answer 19

1 Ambient temperature is the major factor in cooling. A body will not cool in very hot weather.

2 Air movements & humidity accelerate cooling by convection.

3. Water & fluid media: the rate of cooling in cold water is double that of the air.

Question 20

Factors affecting the cooling rate: Individual factors

Answer 20

1. Initial body temperature.
2. Age: infants cool more rapidly because of large surface area/body mass ratio and scanty subcutaneous fat.
3. Posture: A curled body into the fetal position will cool less rapidly than the extended one due to less exposed surface area.
4. Gender & obesity: obese peoples & females cool slower than thin peoples & males (Subcutaneous fat acts as heat insulator).
5. Clothes: Naked bodies cool rapidly than clothed ones. Dry clothes reduce heat loss while wet clothes accelerate cooling.
6. Cause of death: Severe hemorrhage shortly before death causes a more rapid rate of cooling.

• P.M. caloricitv (heating) occurs in conditions in which the body heat may be retained or even increased in the first 2 hours after death, such as:
• Sunstroke & pontine hemorrhage (heat regulation is profoundly disturbed before death).

-Strychnine poisoning & tetanus (great increase in heat production by the muscle contractions).

• Acute bacterial or viral infection

Question 21

MLI of cooling

Answer 21

It denotes the time passed since death.

It denotes the cause of death from rate of cooling.

Differentiation between primary and secondary flaccidity.

Question 22

MLI of hypostasis

Answer 22

1. It is a sure sign of death.
2. It denotes the time passed since death (Post Mortem Interval): The process starts immediately after death, and it becomes pronounced within 3 hours. These patches increase in size and then coalesce together and become fixed in about 8 hours.
3. Its site denotes the position of the body at the time of death. In supine position, hypostasis is observed over the posterior aspects of the body. In prone position, hypostasis is distributed over the anterior aspects of the body. In hanging, hypostasis is observed in the lower limbs; external genitalia and lower parts of the forearms & hands. In drowning, hypostasis is observed in the head; front of the trunk and front of the limbs.
4. It denotes the cause of death from:
   b. Site of hypostasis, as in case of hanging & drowning.
   c. Color of hypostasis which depends on the color of hemoglobin & the mode of death
   - Normally, the color of hypostasis is bluish purple.
   - In severe anemia & hemorrhage hypostasis is light blue.
   - In asphyxia, hypostasis is dark blue due to reduced hemoglobin.
   - In case of red asphyxia (CO, Cyanide & Cold) there is red hypostasis.
   - In case of nitrite poisoning, hypostasis is brown due to formation of met-hemoglobin

d. Extent of hypostasis: More marked in asphyxia and congestion, Ill-defined in hemorrhage and anaemia.

5. Early Hypostasis (during the first 3 hours P.M.) must be differentiated from bruises

Question 23

Discuss the mechanism of rigor mortis (PM rigidity)

Answer 23

It is due to chemical changes involving muscle proteins (actin and myosin).

ATP is responsible for the elasticity & plasticity of the muscles. After death, there is a drop in the muscle ATP level leading to fusion of myosin & actin filaments into a “dehydrated stiff gel” resulting in rigor mortis.

Rigor is initiated when the ATP concentration falls to 85 % of normal and the rigidity of the muscle is maximum when the level declines to 15 %.

Question 24

Factors affecting rigor mortis

Answer 24

1- Temperature:
* In cold weather, delayed onset and offset.
* hot climate : rapid in onset and of short duration (rapid autolysis of ATP).

2- Muscle bulk & age:
* Rigor is more rapid in onset & offset in less developed body musculature. Athletes it is delayed in onset and lasts longer (abundant ATP).

3- Muscle activities before death (cause of death): Convulsions and exertion before death e.g. in electrocution, are usually followed by rapid onset and offset of rigor mortis (depleted ATP).

Question 25

MLI of rigor mortis (PM rigidity)

Answer 25

1- It is a sure sign of death.

2- It denotes the Post Mortem Interval (PMI):Rigor mortis starts 2 hours after death, in the small muscles of the face then the neck, and trunk, followed by the upper extremities then the legs. The last to be affected are the muscles of fingers and toes. It takes 12 hours to cover the whole body, then secondary flaccidity sets in and the muscles start to soften gradually in the same descending order, due to onset of autolysis. Complete body relaxation occurs after 24 hours.

3- The position of the body after death is fixed by rigor mortis.

4- The cause of death is suggested from the time of onset & offset of rigor mortis: see before.

Question 26

MLI of cadaveric spasm (instantaneous rigor)

Answer 26

1. It indicates the muscles in physical activity at the time of death (usually the hands).
2. It indicates the manner of death:
   In suicide: the used weapon is firmly grasped by the victim,
   In homicide: the hands of the victim are found clenching over things belonging to the assailant (hairs or clothes); which helps to identify the assailant.
3. Diagnosis of drowning; the hands of the victim are found grasping sand, mud or sea weeds

Question 27

Compare between Cadaveric spasm and rigor mortis

Answer 27

Question 28

Compare between and secondary flaccidity

Answer 28

Question 29

Factors modifying the rate of putrefaction: Environmental factors

Answer 29

1- Temperature: The optimum temperature is 25- 40 °C at which bacteria flourishes, below 10 °C or above 50 °C bacterial growth is arrested.

2- Medium where the body is disposed: The rate of putrefaction is almost equal after 1 week in air, 2 weeks in water & 8 weeks when bodies are buried in the ground.

3- Moisture: Humidity enhances putrefaction and Dehydration delays putrefaction.

4- Air: Most putrefactive organisms are aerobes so putrefaction is delayed in drowned bodies and sealed coffins.

Question 30

Factors modifying the rate of putrefaction: Individual factors

Answer 30

1- Vascularity: Congested organs & those with high blood content as liver, spleen & gravid uterus putrefy rapidly, while fibrous organs as the prostate & non-gravid uterus are the last organs to putrefy. In drowned bodies putrefaction starts at the head & neck.

2- Age: Newly born & still-born putrefy slowly due to absence of bacteria inside the gut, and also their bodies cool rapidly leading to slowing of putrefaction.

3- Cause of death: Rapid rate; in septicemia. Slow rate; in deaths due to hemorrhage, metallic poisoning as arsenic (dehydration and bactericidal).

Question 31

MLI of Adipocere

Answer 31

It denotes long submersion under water.

It denotes the time passed since death from its extent & texture. It starts at 3 weeks in the subcutaneous fat of cheeks, breasts, buttocks & abdomen, and takes about 6 months to cover the whole body.

It helps personal identification as the changes in the subcutaneous tissues keep features of the face & body contour in a recognizable form.

It may indicate the cause of death since injuries are easily recognizable.

Question 32

MLI of mumification

Answer 32

1. It denotes exposure to hot dry atmosphere.
2. It indicates the time elapsed since death from the extent of dryness and shrinkage of tissues as it starts in lips, nose, fingers and toes after 3 weeks. Complete mummification of a body requires 3-12 months depending on the size of the body and the atmospheric condition.
3. It helps personal identification in some instances, as facial features are preserved.
4. It helps identification of the cause of death since injuries are preserved.

Question 33

Discuss the characteristics of maceration

Answer 33

1. Maceration starts immediately after IUFD (Intra Uterine Fetal Death).
2. After 5-7 days, maceration is fully manifested by: Softening of the dead fetus that it flattens when placed on the table. There is over-mobility of the joints. Over-riding of skull bones with hyperflexion of the spine due to absorption of C.S.F. This may be detected by X- ray on the skull and is known as “Spaulding sign”.

Brown peeled skin.

Gases are NOT formed because maceration is a sterile process.

Question 34

MLI of maceration

Answer 34

1. It indicates IUFD (still birth).
2. It nullifies a false allegation of a live birth baby (inheritance,
   infanticide & induction of abortion).
3. It indicates time of fetal death from its extent.

Question 35

PM eye changes signs and time

Answer 35

-Loss of corneal and light reflexes: @ death

-Segmentation of retinal vessels: 15 min

-IOP is Zero: 2 hrs

-Opacity of the cornea: 2 hrs

-Tache Noire: 3-4 hrs

Question 36

PM primary flaccidity changes signs and time

Answer 36

Flaccid reactive muscles: @ moment of death till rigor mortis

Question 37

PM cooling changes signs and time

Answer 37

1-1.5 °C per hr. till equilibrium with surrounding temperature: Up to 18 hrs

Question 38

PM hypostasis changes signs and time

Answer 38

Patches: at 3 hrs
Fixed: at 8 hrs

Question 39

PM Rigor Mortis changes signs and time

Answer 39

Face and lid muscles: 2hrs

Covering all of the body: 12 hrs

Disappears: 24 hrs

Question 40

PM putrefaction in winter signs and time

Answer 40

Greenish staining of lower abdomen: 2 days

Whole body greenish-black staining: 1 week

Burst abdomen and larvae: 2 weeks

Bones attached by ligaments: 6months

Separate bones: 12 months

Question 41

Adipocere formation signs and time

Answer 41

Start to appear in S.C. fat: 3 weeks

Whole body fats: 6 months

Question 42

Mummification formation signs and time

Answer 42

Start: 3 weeks

Complete body: 3-12 months

Question 43

Maceration signs and time

Answer 43

Fully manifested: 5-7 days after IU death

Question 44

Medico legal Importance of abrasions:

Answer 44

1. Abrasions denote signs of violence and resistance
2. Abrasions take the shape of the causal object, e.g. nail abrasion in smothering and throttling, ligature marks in strangulation and hanging,
3. Site of abrasion occurs exactly at the site of impact eg. Semi lunar nail abrasions around the neck in throttling, and around the mouth and nostrils in smothering.
4. Site of abrasion reflects the sort of the assault eg. Abrasions at the inner aspects of the thighs denote rape.
5. The direction of injury and position of the assailant is detected in case of linear scratches where tags of epithelium are collected at the end of the wound.
6. The age of abrasion indicate the date of the crime from:

First two days: covered by a soft scab.
After three days: covered by dry scab.
After one week: the scab falls leaving a coppery red area.
After three weeks: disappears leaving no scar.

7. Abrasions help to identify the assailant from: Finger nail abrasions may tell whether he is left or right handed or missing a finger.
8. A.M. abrasions should be differentiated from P.M.: A.M. abrasions are characterized by the presence of vital reactions (redness, healing and sepsis). Post-mortem abrasions are due to rough handling of dead bodies.
9. Abrasions help to differentiate between: Cut and contused wounds, Hypostasis and bruises. Inlet and exit wounds in firearm injuries (present around inlet).

Question 45

Medico legal importance of bruises:

Answer 45

1. Bruises denote violence or resistance as in case of rape and murder.
2. Bruises take the shape of the causal object (patterned injury):

Blow with a stick —> two elongated parallel lines (railway bruises).

Human bite —> two curved rows of bruises that may be
accompanied by abrasions.

Animal bite—> two parallel rows of bruises.

Whip mark —►curvilinear bruises twisted around the body.

Pinch —> two identical small rounded bruises.

3. Site of bruises is usually the same site of force application, but sometimes it may shift by gravity, Blow to the forehead may appear as a black eye due to gravitation of blood
4. Age of the bruise coincides with the date of the crime: First bright Red, then Blue, then Green, then yellow; between each color is 2-3 days
5. A.M. bruises should be differentiated from P.M.: A.M. bruises are characterized by presence of swelling, color changes and may be of any size. P.M. bruises may occur after death as trauma crush the capillaries containing fluid blood, but as there is no blood
   pressure; thus the amount of the expelled blood is very small.
6. Bruises should be differentiated from hypostasis

Question 46

Compare between bruising and hypostasis

Answer 46

Question 47

MLI of bite marks

Answer 47

The bite is considered as a print or a cast from the teeth in the form of abrasions and bruises, which helps in identification of the assailant by comparing it with his teeth.

The age of the bite, from the process of healing, could be compared with the date of the assault.

Bite marks are frequently present in sexual crimes, murder or child abuse.

Human bite is distinguished from animal bite

Question 48

Compare between cut and contused wounds

Answer 48

Question 49

Discuss the characters of stab wounds

Answer 49

1. Cleanly cut edges.
2. They are more deep than long.

3.They give an idea about the causal instrument:
Single sharp bladed (knife) -► one acute angle.
Double sharp bladed (dagger) —> two acute angles.
The length of the wound approximately equals the breadth of the weapon unless the wound is enlarged during withdrawal of the weapon. The depth of the wound equals length of the weapon

4. A broken tip of the weapon could be found in the wound; helps in ID
5. They are very dangerous and fatal

Question 50

Discuss defense wounds

Answer 50

These are wounds sustained by the victim to defend himself.

In case of hitting: there will be abrasion or bruises on the outer side of the forearm, back of hands and fingers that may be broken in an attempt by the victim to shield himself.

In kicking: defense bruises occur on the outer side of the thigh as
the victim tries to protect his genital region.

In attacks by knife: The blade may be gripped by the victim, so that cut wounds may occur across the fingers and the palm.

Defense wounds may be of value in differentiating homicide and suicide. But, their absence does not rule out a homicidal attack, for it is possible for the victim to be incapable of defense

Question 51

Characters of Fabricated Wounds

Answer 51

1. Superficial and relatively harmless.
2. In safe sites which are easily accessible to the victim
   .
3. They are inflicted on a bare skin so no corresponding tears of clothes are detected.
4. Non consistency between the findings of examination and the history taken especially regarding the date of the crime and the type of the weapon.

Question 52

Cause of death in wounds (read 43-46)

Question 53

Difference between homicidal and suicidal cutthroat

Answer 53

Question 54

Discuss each type of hymen varieties and mention which ones cause medicolegal issues

Answer 54

Question 55

Describe the features of full term infant

Answer 55

a) Weight about 2500-3500 gm. & 50 cm. length.

b) Umbilical cord is 50 cm, and joins the body mid-way between xiphistermum and symphysis pubis.

c) O.C. at upper end of tibia appear and at lower end of femur (5mm).
d) Testicles in the scrotum.
e) Posterior fontanel is closed.
f) Head circumference is 13 inches.
g) Head hair 3 cm.
h) Nails beyond fingers but just reach the ends of the toes.

Question 56

Thermal injuries in violation of human rights

Answer 56

Doughnut Sign: Forced contact with a bath of hot water spares the bottom of the buttocks, while the surrounding circumferential skin
is scalded.

Zebra Sign: Hip and knee flexion spares skin folds in the groin resulting
in linear areas of normal skin within larger areas of scalded skin resembling zebra stripes.

Stocking and Glove: The entire hand or foot is scalded circumferentially with a clearly defined upper limit of demarcation.

Dry Burn: Caused by hot metallic objects (fork/knife/scissors) —► contact imprints with thick scar formation.

Cigarette burns: Very common, leave a circular mark with a tail if the cigarette is brushed against the skin

Question 57

Discuss the stages of asphyxiation

Answer 57

1 - Stage of dyspnea: .(reversible) : Lack of oxygenation increases the level of reduced hemoglobin resulting in stimulation of the respiratory center.

C/P: Forced respiration with increased rate and depth (dyspnea). 4- Facial congestion and the onset of cyanosis.
Anxiety and confusion.

2-Stage of convulsions (reversible)
Cerebral irritation due to anoxia and hypercarbia.

C/P :
-Increased cyanosis and constricted pupils.
- Generalized convulsions —> increase in blood pressure—* rupture of submucous and subserous capillaries —► appearance of petechial hemorrhages.

Stage of paralysis: irreversible brain damage (coma)
Clinical picture:

Loss of consciousness,
Irregular breathing breathing,
Deepening of cyanosis,
Drop of blood pressure,
Muscle relaxation (evacuation of bladder and vomiting).
Dilated fixed pupils.
Death occurs in about 5 minutes

Question 58

The Classical External Signs of Asphyxia: 6

Answer 58

1. Cyanosis: dark blue discoloration (lips and nails) depends on the absolute amount of reduced hemoglobin
2. Facial edema with petechial hemorrhages.
3. Prominent eye balls (retro-orbital edema) with sub­ conjunctival hemorrhage.
4. Protruded tongue and bloody froth from the mouth and nostrils (rupture of the capillaries in the air passage).
5. Dark blue hypostasis.

Question 59

Post mortem picture of smothering

Answer 59

A. General: Signs of asphyxia and Signs of struggle or resistance

B. Local:
Semilunar nail abrasions and bruises detected at external respiratory orifices which coincide with the number and distribution of the nails (four on the left side and one on the right side if the assailant used the right hand and vice versa if the left hand was used). These findings may be absent if a soft pad or pillow was intervening between the hands and the face.
Bruises and contused wounds in the inner aspect of the lips, cheeks and gums as they were pressed against teeth which may be broken.

Question 60

Mechanism of death in chocking (blocking of internal respiratory canal)

Answer 60

Mechanism of death: either

I. Asphyxia: where airway obstructed by foreign body which may be partial that is completed by laryngospasm or increased mucous secretion, with appearance of external and internal signs of asphyxia.

II. Reflex vagal inhibition (RVI): rapid silent death from vasovagal cardiac arrest (Cafe coronary)

Question 61

Post mortem signs of suffocation

Answer 61

Caused by decrease in atmospheric oxygen as in plastic bag suffocation.

The ‘classic signs’ of asphyxia are almost always absent.

1- It is very rare to find any petechial hemorrhages, as these are mainly due to venous obstruction, which is absent in suffocation.

2- Congestion and cyanosis are often absent, and the autopsy findings are essentially negative.

Question 62

Methods of deaths in throttling

Answer 62

1- Mechanical anoxia is the chief cause of death.
2- RVI (compression of carotid sinus).
3- Cerebral anemia (compression of carotid artery).
4- Delayed edema of the glottis.

Question 63

Post mortem picture of throttling

Answer 63

A. General. External signs of asphyxia.
B. Local

1- Semilunar nail abrasions and bruises on the front and sides of the neck. Their distribution and number help for detecting the identity of the assailant (right or left handed or missing a finger), his position with respect to the victim and whether he used one or both hands.

2- Linear abrasions; due to the movement of the victim’s fingers along his neck in an attempt to release the pressure.

3- Hemorrhage and bruises under the skin and in the muscles of the neck.

4- Internal fracture of greater horn of hyoid bone or subluxation
of the joint
.
5- Damaged larynx and fracture or split of the thyroid cartilage.

Question 64

Post mortem picture of strangulation

Answer 64

A. General: signs of asphyxia.

B. Local

Ligature mark:.
Formed of abrasions and contusions and surrounded by congestion, petechiae and hyperemia
Takes the pattern and size of the ligature; eg.:
- Well defined and deep if a wire or thin cord is used,
- Diffuse and faint if a soft fabric is used,

Transverse and located just below the laryngeal prominence

Complete circle involving the whole circumference of the neck.

The mark may be absent if the ligature is removed immediately
after death.

Question 65

Mechanism of death in hanging

Answer 65

1- Cerebral anemia: The commonest, due to stretch of the carotids and their elongation with subsequent narrowing. This explains the rapid loss of consciousness (victim cannot save himself).

2- RVI: due to pressure on the carotid sinus.

3- Mechanical asphyxia due to backward displacement of the base of the tongue.

4- Tearing of the medulla: following Fracture dislocation of 1st and 2nd cervical vertebrae. Common with “Judicial hanging” due to the long drop of more than two meters.

Question 66

Signs of hanging

Answer 66

A. General
1- Signs of asphyxia.
2- Hypostasis in the lower parts of the body (lower limbs, hands, lower abdomen & genitalia).
3- Engorged genital organs with ejaculation in males.

B. Local

1- Ligature mark, as in strangulation but: Incomplete circle around the neck as it is absent at point of suspension (in fixed Knots), Asymmetrical: deepest opposite the point of suspension and fades gradually upwards to be absent at the site of the knot. Oblique and located high up in the neck above larynx

2- Dribbling of saliva which is an indicator of ante-mortem hanging, due to pressure on the sub mandibular gland

3- Neck muscles show bruises and lacerations.

4- Fracture of hyoid bone and larynx.

Question 67

Compare between strangulation and hanging ligature marks

Answer 67

Question 68

Post mortem picture of traumatic (crush) asphyxiation

Answer 68

It provides the most remarkable demonstration of the ‘classic signs’ of asphyxia.

1- The most classic feature is the blue congestion of the face, neck and upper part of the chest. Together with pallor at the site of compression. There is a distinct line of demarcation between the congested and the pale parts.

2- The conjunctivae are grossly congested and hemorrhagic.

3- There may be local bruises and abrasions from the compressing weight.

4- Other injuries: contusions and abrasions of chest wall, fracture ribs or sternum and rupture of heart or lungs.

Question 69

Cause of death in typical (wet) drowning

Answer 69

1. Mechanical anoxia: filling of air passages with water results in
   deprivation of oxygen and irreversible cortical brain damage.
2. Profound fluid and electrolyte imbalance:

i. in freshwater drowning, there is a massive absorption of water
through the alveolar membranes, which could amount to 70% of the original blood volume within 3 minutes. This leads to hypervolemia and cardiac overload. Also, hemodilution occurs with resultant hemolysis of red cells and potassium release leading to severe hyperkalemia and powerful myocardial toxemia. Death typically takes about 4-5 minutes.

ii. in seawater drowning, the hypertonic medium causes a withdrawal of water from the plasma into the lungs and a rise in plasma sodium concentration. This condition is less deleterious to heart function and explains the longer survival time in seawater immersion (8-12 minutes).

Question 70

B. Atypical, drowning cause of death

Answer 70

1. Laryngeal spasm: in about 20% of cases of drowning leading to a hypoxic death from closure of the airway preventing water entry, the so-called ’dry drowning’, in which, the lungs appear normal in all aspects.
2. Hydrocution or submersion inhibition: death is due to cardiac arrest as a result of vagal inhibition by immersion in cold water.
3. Post-immersion syndrome or near drowning: Death results from cerebral anoxia with irreversible brain damage within half an hour to several days after resuscitation. Also, pulmonary infection (contaminated water) or heart failure (exhaustion) may end fatally from pulmonary edema.
4. Traumatic conditions: e.g. Head injuries when the victim’s head strikes a rock in shallow water leading to death under water or in faulty diving or boat accidents.

Question 71

Discuss the PM picture of drowning

Answer 71

1- Goose skin: due to contraction of erector pilae muscles of hair follicles because of coldness during life and rigor mortis after death.

2- Washer-woman hands Corrugated sodden skin of hands and feet occurs after 24 hours submersion.

3- Peeling of epidermis: especially that of hands and feet in the form of gloves and sockets, due to accumulation of putrefactive gases between dermis and epidermis.

4- Immersion effects on Postmortem changes:
-Cooling: rate of cooling under water is double than that in air.
-Hypostasis: pale in color, and located in the head, neck, shoulders and upper limbs.
-Putrefaction: takes double the time as that in air.
-Adipocere: appears after 3 weeks and completed in 6 months.

Sure signs:
1- Froth: composed of a mixture of air, water &mucous that resulted from the vigorous respiratory movement. It is abundant, whitish, odorless, fine small bubbled foam, present at the mouth and nostrils.

2- Cadaveric spasm: The victim catches firmly sand, mud or sea weeds, denoting life during drowning. The material clenched in the hands indicates the place of submersion.