Forensic Medicine

Question 1

How to find out if a bone is human or not?

Answer 1

-Visual identification: Complete bone such as skull
-Precipitin test: Bone fragments (Find out if it is human or animal)

Question 2

Identification of sex from skull (Male vs Female)

Answer 2

1:Parietal and frontal eminence: Prominent vs smooth
2:Superciliary ridges: Prominent vs Less prominent
3: Frontonasal junction: Angular vs smooth
4:Mastoid process: Long vs Short
5:Occipital condyle: Long narrow vs Short broad

Question 3

Identification of sex from sternum

Answer 3

Size: Longer/broader VS Shorter/narrow
Relation between the body and the manubrium: Body x2 length of manubrium VS Less than x2 length of manubrium

Question 4

Identification of sex from hip bone

Answer 4

Iliac crest: More curved VS Less curved
Greater sciatic notch: Narrow and deep VS Wide and shallow
Obturator foramen: Oval vs triangle
Acetabulum: Deep and wide VS shallow and narrow
Iliopectineal line: Sharp VS smooth
Body of pubis: Long and narrow VS short and square
Periauricular sulcus: Shallow and ill-defined VS deep in multipara
Subpubic arch: Inverted V-shape vs Inverted U-shape
Pelvic cavity: Deep and narrow VS shallow and wide

Question 5

Identification from sacrum (Sex)

Answer 5

Shape: Long, narrow and curved VS short, wide and straight
promontory: Projected Vs less projected
Sacroiliac Joint: Reaches the 3rd sacral piece Vs Reaches the 2nd sacral piece
Coccyx: Less movable VS more movable

Question 6

Identification of age from skull

Answer 6

1-Dimension (HC is 13 in at full term, length 5in and width 4in)
2-Fontanels: Posterior closes at full term, Anterior at 2 years
3-Sutures:
- Frontal suture: close at 2 years.
- Sagittal suture: close at 25-30 years.
- Coronal suture: close at 40 years.
- Lambdoid suture: close at 50 years.
- Basi-occipital bone unites with basi-sphenoid at 23 years.
4-Mandible: Identification of age from mandible depend on the angle between the body of the mandible and the ramus:
- Infant: the angle is obtuse.
- Middle age: the angle is right.
- Old age: the angle is obtuse and the alveolar margins become absorbed.
5- Teeth:
Milk dentition:
- Central incisor: 6 months.
- Lateral incisor: 9 months
- First milk molar: 12 months
- Canine: 18 months.
- Second milk molar: 24 months.
Permanent dentition:
- First molar: 6 years.
- Central incisor: 7 years.
- Lateral incisor: 8 years
- First bicuspid: 9 years.
- Second bicuspid: 10 years.
- Canine: 11 years.
- Second molar: 12 years.
- Third molar (wisdom tooth): 18-25 years.

Question 7

Ossification centers intrauterine life

Answer 7

-5 months Calcaneus
-7 months Talus
-8 months Lower end of femur
-9 months Cuboid, upper end of tibia and lower end of femur (0.5cm in diameter)

Question 8

Ossification center after birth

Answer 8

-1 year: Head of femur and humerus
-2 year: Lower end of radius, tibia and fibula
-6 year: Lower end of ulna, upper end of radius and medial epicondyle
-12 year: upper end of ulna and lateral epicondyle

Question 9

Upper limb union of epiphysis

Answer 9

Age Union of epiphysis
14 years Trochlea with capitulum of humerus
15 years Trochlea and capitulum with the shaft of humerus
16 years Lateral epicondyle and upper end of ulna
17 years Medial epicondyle and upper end of radius
18 years Metacarpal and phalanges with shafts
20 years Head of humerus and lower end of radius & ulna
23 years Sternal end of the clavicle

Question 10

Union of epiphysis of lower limb

Answer 10

16 years Lesser trochanter of femur
17 years Greater trochanter of femur
18 years Head of femur and lower ends of tibia and fibula
21 years Lower end of femur and upper end of tibia

Question 11

Union of epiphysis of Hip bone

Answer 11

6 years Pubic ramus unites with ischial ramus
15 years Ileum, ischium and pubis unite at the acetabulum (y shaped suture disappears)
21 years Ischial tuberosity
23 years Iliac crest

Question 12

Union of epiphysis of Sternum/hyoid bone and medullary cavity of humerus

Answer 12

1- Sternum: xiphoid process unites with the body at 40 years and the manubrium unites with the body at 60 years.
2- Hyoid bone: the greater cornu unites with the body at 40 years.
3- Medullary cavity of the humerus: it reaches the surgical neck at 30 years and reaches the anatomical neck at 33 years.

Question 13

General characters of negroid skull

Answer 13

1- Persistent frontal suture.
2- Absence of H-shaped suture (the four bones of the skull meet at one point).
3- Flat nasal bridge with wide nasal apertures.
4- Flat palate with prognathism (protrusion of upper jaw).
5- Dolichocephaly (elongation of the antero-posterior diameter of the skull).
6- Small mastoid process.

Question 14

Identification of the dead-

Answer 14

1- Clothes: are examined for tailor’s labels, tears, missing buttons, identity cards, letters, pocket, books… etc.
2- External appearance: color of skin, hair, eyes, shapes of nose, mouth, ears…etc.
3- Sex:
- External examination
- Internal examination: e.g. uterus, ovaries, undescended testis…etc.
- Cell sexing:
Sex chromatin test: female cells show Barr body in the form of chromatin mass attached to the inner surface of the nuclear membrane, but male cell do not show that Barr body.
Davidson body test: white blood cells of females show a thin stalked drum-stick projection in the polymorph nucleus.
4- Age
■ During the first 2 years of life:
a) Milk dentition.
b) Bone.
c) Body weight:
▪ At birth → 3-3.5 kg
▪ At 6 month → 6 kg
▪ At 12 month → 9 kg
▪ At 2 years → 12 kg
■ Between 2-6 years:
d) Body weight: age in years = (weight in kg-8)/2.
e) Ossification centers.
■ Between 6-25 years:
a) Union of epiphysis.
b) Ossification centers.
c) Signs of puberty.
■ Above 25 years:
a) Skull sutures.
b) Sternum and hyoid bone.
c) Signs of senility: grayness of hair, wrinkles of skin, etc…
5- Race: Race can be determined from: color of skin, hair, iris, skull features…etc.
6- Finger print: it is the most accurate method for identification.
7- Social status and occupation may be identified from the clothes or stain on the fingers.
8- Examination for presence of congenital malformation, birth marks, tattoo marks, operations, scars, …etc

Question 15

Ages of medicolegal importance

Answer 15

-6 years: Age of starting education
▪ Eruption of first permanent molar.
▪ Pubic ramus unites with ischial ramus.
▪ Appearance of ossific centers of upper end of
radius, lower end of ulna & medial epicondyle

-7 years: Age of discrimination between right and wrong
▪ Eruption of permanent central incisor
▪ Ossific center occupies 2/3 of the breadth of
lower end of radius

-14 years: Under this age the boy cannot commit the crime of rape
Trochlea units with the capitulum

-15 years: - Age of end of maternal custody.
-Age of getting identity cards.
- Union of y-shaped suture between ileum,
ischium and pubis of hip bone.
- Union of trochlea and capitulum with the
shaft of humerus

-18 years - Legal age of marriage of
male and female
- The age of female consent
in rape.
- Age of getting driving
license.
- Age of governmental
employment.
- Voting in election.
- Criminal responsibility.
- First military call.
In male: union of epiphysis of metacarpal and
phalanges, head of femur and lower ends of
tibia & fibula.
In female: union of epiphysis of head of
humerus & lower end of ulna and radius.

-21 years - Age of full civil rights
- Age of recruitment of military service
In male: union of epiphysis of lower end of
femur and upper end of tibia & ischial tuberosity.
In female: union of sternal end of clavicle,
epiphysis of iliac crest, basi-occiput with basisphenoid.

-30 years - Age for being a member of
people assembly
Closure of sagittal suture but coronal suture is
still open

-35 years - Legal age of being president
As age 30

-60 years - Pension age
Manubrium & the body of sternum

Question 16

Definition and stages of Death

Answer 16

Death is the permanent cessation of vital functions (Cardiac, respiratory and CNS)

1- Somatic death (clinical death) in which there is permanent cessation of cardiac, respiratory and CNS functions.
2- Molecular life (physiological window) is the period between clinical and cellular death.
3- Cellular death (molecular death) in which the tissues and their constituent cells are dead. Cellular death follows the ischemia and anoxia consequent to cardiorespiratory failure. Different tissues die at different rates, depending on their ability to function without oxygen. The cerebral cortex can withstand only a few minutes of anoxia (3-8 min), whereas muscle survive for many hours after the cessation of the circulation.

Question 17

Evidence of molecular life and its medicolegal importance?

Answer 17

• Muscles respond to electric stimulation for 3 hours.
• Motile sperms were found in the epididymis for few days after death.
• Some chemical and enzymatic activities continue after death.
  Medicolegally:
  The period of molecular life is the period where organ transplantation can be done. The viability of the transplantable organs falls after somatic death. The liver must be taken within 15 min., the kidney within 45 min., and the heart within one hour.

Question 18

What is suspended animation

Answer 18

It is a death like state (apparent death) in which there is temporary suspension of heart beats and respiration. It is a state where the vital processes of the body are depressed to a minimum compatible with life. However, respiration is not ceased at cellular level, so resuscitation is still possible. It may occur in severe shock following an accident, electric shock, barbiturate, or narcotic poisoning. It can be induced voluntarily in Yoga practitioners. It cannot be certainly differentiated from death when based on ordinary clinical methods therefore additional tests, as ECG and EEG must be done.

Question 19

Medicolegal importance of Suspended animation?

Answer 19

Prevent premature burial (live burial). It is a general rule that a dead body not transferred from the word to the postmortem room unless 4 hours have been passed since occurrence of somatic death. Also, burial is not allowed before lapse of 8-10 hours.

Question 20

Immediate signs of death?

Answer 20

1-Cessation of circulation: Primary marker of death, confirmed by prolonged auscultation of the chest exclude hearts sounds though, as in life, a thick chest wall may muffle feeble heartbeat and ECG.
2-Cessation of respiration: Respiration is more difficult to confirm, especially in deep coma such as barbiturate poisoning, and prolonged listening with a stethoscope over the trachea or lung fields is necessary. Some procedures such as saucers of water on the chest and feathers before the nostrils are only of historical interest.
3-Signs of brain death:
- Deep irreversible coma and loss of all reflexes.
- No reaction to painful stimuli.
- Muscular flaccidity occurs immediately upon failure of cerebral and cerebellar function. All muscle tone is lost (dropping of jaw and mydriasis).
- Flat electroencephalogram (EEG).
- Signs of brainstem death

Question 21

Signs of brainstem death

Answer 21

Brain stem death is irreversible stoppage of all vital centers in the brain stem which maintain spontaneous breathing and circulation (permanent cessation of brain stem functions). Cortical death does not mean brain stem death, so flat EEG is not diagnostic of brain stem death.

When the higher levels of cerebral activity are selectively lost, either from a period of hypoxia, trauma, or toxic insult, the victim will exist in a vegetative state. In vegetative state, the survival of the brainstem ensures that spontaneous breathing will continue and therefore cardiac function is not compromised. The victim can remain in deep coma almost indefinitely.

Question 22

Diagnosis of brain stem death

Answer 22

1- No corneal and light reflexes.
2- Absent vestibulo-ocular reflex.: Barany’s test (caloric test): No eye movements occur after installation of 5 ml iced water into the ear canal.
3- Absent Cantellis sign (Doll’s eye sign) oculocephalic reflex : Lag of the eye movement as if the gaze is fixed occurs in case of rapid turning of the head.
4- No motor response within cranial nerve distribution.
5- No gag reflex to bronchial stimulation by a catheter passed down the trachea.
6- No respiratory movements occur when the patient is disconnected from the ventilator to ensure that co2 concentration in the blood rises above threshold for stimulating respiration.

Question 23

Early signs of Death

Answer 23

1- Changes in the skin: Pallor and loss of skin elasticity.
2- Changes in the muscles:
- Primary flaccidity: Relaxation of the muscle and loss of the muscle tone, leading to drop of the lower jaw, the joints are flexible and the sphincters relax leading to incontinence in urine and stool.
- Contact flattening of the convex parts e.g. shoulder blades, buttocks and calves due to loss of muscle tone and elasticity.
3- Changes in the eye:
- Loss of the corneal and light reflexes leading to insensitive corneas and fixed non-reactive pupils. Though the iris responds to chemical stimulation for hours after somatic death.
- The intraocular tension decreases rapidly, as it is dependent upon arterial pressure for its maintenance. Normal tension (24 mm Hg) is halved at death (12 mm Hg), falls to as low as an eighth (3mm Hg) in 30 minutes, and was nil by 2 hours after death.
- The cornea soon loses its normal luster and becomes opaque after 2 hours because of accumulation of dust on the mucous film deposited on the cornea and failure of lachrymal moistening but it may remain lustrous in case of asphyxial death due to excessive fibrinolysin that dissolves the mucous film on the cornea.
- Ophthalmoscopic examination shows: pale retina, segmented retinal veins (15min after
death), empty retinal arteries.

Question 24

Factors affecting Postmortem cooling

Answer 24

1- Fat: fatty persons cool slowly (fats act as insulator)
2- Age: newly born and infants cools rapidly due to large surface area in relation to body weight
3- Atmospheric temperature: in hot climate dead body loses heat slower than in cold weather
4- Body temperature at time of death.
5- Posture: an expanded body position loses heat faster than the curled up fetal position
6- Edema delay cooling.
7- Clothing: a naked body cools faster than heavily clothed one.

Question 25

Medicolegal importance of postmortem cooling?

Answer 25

1- It denotes time passed since death.
2- Differentiates between primary flaccidity (hot) and secondary muscle flaccidity (cold)

Question 26

Postmortem staining (Liver mortis/Hypostasis) Definition, Time and site?

Answer 26

Bluish-purple discoloration of the skin in dependent areas of the body due to accumulation of blood in the small vessels of these areas secondary to gravity as a result of cessation of circulation.

Time: Heart stops –> Evident at 30mins-2hrs –> Maximum coloration at 8-12hrs (fixed)

Site: In dependent areas of the body and absent over compressed parts.

Question 27

Medicolegal importance of Postmortem Staining (Liver mortis/hypostasis)

Answer 27

1- It is a sure sign of death.
2- It denotes time passed since death from its extent.
3- It denotes the position of the body after death and whether the body has been moved or not. For example if hypostasis is present in the back, chest and abdomen this indicates change in the position before the lapse of 8 hours (before fixation of hypostasis).
4- Cause of death may suggest from hypostasis by:
- Its extent: well-marked in asphyxia, ill marked in hemorrhage.
- Its color: Pale blue in natural death, Deep blue in asphyxia, Cherry-red color in deaths due to carbon monoxide, cyanide and cold (red asphyxia).
- Its site: In case of hanging, hypostasis occurs in lower limb, forearms and lower part of abdominal wall. While in bodies submerged in water hypostasis is formed in face, shoulder and front of the chest.
5- Hypostasis must be differentiated from bruises.

Question 28

Difference between hypostasis and bruises

Answer 28

▪ During life ▪ After death
▪ At any site ▪ Most dependent part
▪ Swelling ▪ No Swelling
▪ Abrasion in the skin ▪ No abrasion
▪ Show different color ▪ One color
▪ Blood inside tissue ▪ Blood inside blood vessels
▪ Microscopic exam: Show vital reaction ▪ No Vital reaction

Question 29

Rigor mortis definition

Answer 29

Rigor mortis is that state of the muscles in a dead body when they become stiff or rigid with some degree of shortening. The phase of primary relaxation of the muscles continues for about an hour which is followed by stiffening or rigidity. It indicates molecular death of the concerned muscles. It is due to the disappearance of adenosine triphosphate (ATP) from muscle. ATP is the basic source of energy for muscle contraction. After death, generation of ATP stops, though its consumption continues. In the absence of ATP, actin and myosin filaments become permanently complexes and rigor mortis sets in.

Time: 2-4hrs after death, complete at 6-12hrs. Small muscles –> Upper extremities –> Lower extremities.

Question 30

Factors affecting rigor mortis

Answer 30

1- Muscular exertion prior to death will produce a decrease in ATP and speed up the onset of rigor mortis. Some factors that cause a marked decrease in ATP prior to death are violent or heavy exercise, severe convulsions. All of these factors may cause rapid onset of rigor mortis,
2- Age and muscular development:
Its onset may also be very rapid in infants and old people. In emaciated individuals, rigor mortis is very weak, and comes and passes off early.
3- Temperature:
Like any chemical reaction the speed of onset and the duration of rigor are modified by temperature. Any disease or environmental factor that raises body temperature accelerates the onset and offset of rigor mortis.

Question 31

Medicolegal importance of rigor mortis

Answer 31

1- It is a sure sign of death.
2- It denotes time passed since death from its extent and disappearance.
3- It denotes the position of the body after death and whether the body has been moved or not.
4- Cause of death may be suggested from rigor mortis which occurs rapidly in case of death following severe muscular exertion e.g., convulsions occurring in strychnine, tetanus, electrocution
5- Rigor mortis must be differentiated from other causes of muscle stiffening (Cadaveric spasm or Heat/cold stiffening)

Question 32

Medicolegal importance of Cadaveric spasm

Answer 32

• In case of suicide the victim is firmly grasping the weapon. Cadaveric spasm cannot be simulated by placing the weapon in the victim hands.
• In case of drowning the victim is firmly grasping weeds, mud, sand which confirm that he was alive when getting to water (sure sign of drowning).
• In case of homicide the victim may be grasping anything belongs to the assailant.

Question 33

Differences between Cadaveric spasm and rigor mortis?

Answer 33

Time: Antemortem (A.M) VS Postmortem (P.M)
Mechanism: Nervous tension VS Chemical (depletion of A.T.P)
Muscles involved: One group of voluntary muscle VS All muscles voluntary and involuntary
Incidence: Some cases of death VS All cases of death

Question 34

What are cold and heat stiffening ?

Answer 34

• Cold stiffening:
  In extreme cold, temperature below zero, the muscles may harden because the body fluids may freeze. Crepitating sounds are heard on moving the joints. When the body is warmed up, true rigor may supervene.
• Heat stiffening:
  Heat applied to the body also causes stiffness of the muscles, as the proteins of the tissues become denatured and coagulated as in cooking. The degree and depth of change depends on the intensity of the heat and the time for which it was applied. Marked shortening occurs, causing the well-known ‘pugilistic attitude’ of a burned body. This is because of the greater mass of flexor muscles compared with extensors, which forces the limbs into flexion and the spine into opisthotonos. These changes are purely postmortem (i.e., pugilistic attitude is not a sign of antemortem burn)

Question 35

Factors used to determine the time of death

Answer 35

1- Ocular signs.
2- Response of muscle to electric stimulation (electric stimulation cause muscle contraction up to three hours after death).
3- Rate of cooling.
4- Extent of livor mortis.
5- Appearance or disappearance of rigor mortis.
6- Degree of decomposition.
7- Mummification.
8- Adipocere.
9- Other changes: in the blood, cerebrospinal fluid chemical changes, stomach contents and insect activity

Question 36

How can you differentiate between suicidal, homicidal and accidental death? (Circumstantial evidence and the scene of the crime)

Answer 36

1- History:
In suicide: History of failure e.g. (failure in love or in exams) or history of financial troubles. Also, previous attempt at suicide may be present.
In homicide: History of threatening by some enemy is present.
In accident: History of accident
2- A suicide note: In suicidal death, this note is present beside victim’s body with his own handwriting.
3- The condition of the room:
In suicide: no disarrangement of furniture and the door is locked from inside.
In homicide: the disarrangement of furniture is a characteristic feature.
In accident: The condition of the scene differs according to the type of the accident
4- The presence of anything belong to the assailant in homicidal death at the scene of crime e.g. fingerprint, bloodstain, hair, button, suggest homicide.

Question 37

How can you differentiate between suicidal, homicidal and accidental death? (Examination of victim)

Answer 37

1- Victim’s sex:
In suicide: victim is usually male because women are less inclined to physical
violence and not accustomed to use weapon.
In homicide and accident: victim may be male or female.
2- Position of victim’s body:
In suicide: victim is usually present in door, in his room and the door is locked from inside and in front of mirror soiled with blood as in suicide with cut throat.
In homicide and accident: victim may be present anywhere whether indoor or outdoor.
3- Victim’s clothes:
In suicide: victim usually bares the skin.
In homicide and accident: site of tears and blood stain coincide with site of injury.
4- Cadaveric spasm:
In suicide: victim is usually firmly grasping weapon, which carry fingerprints of the victim.
In homicide: victim is usually grasping anything belonging to assailant e.g. button, some hair, a piece of clothing….
In accident: Cadaveric spasm may occur in some types as accidental drowning.
5- Site of blood stain:
It can differentiate between suicidal and homicidal death as in cut throat.
In a suicidal cut throat: the blood is trickling from the neck wound to the front of the victim’s; clothes down
to his feet.
But in the homicidal cut throat, blood is trickling to the back of the victim.
6- Other body injuries:
In suicide: another attempt at suicide e.g. cut on radial artery at the wrist. Also, in suicidal firearm injury, burning and blackening may be present at the tips of the left hand fingers, which were used to fix the weapon’s muzzle to the right temple during shooting.
In homicide: Victim’s body may show defensive wounds e.g. small cuts in palm of hand, abrasion, and bruises

Question 38

How can you differentiate between suicidal, homicidal and accidental death? (Examination of wound)

Answer 38

1- Nature of wound: stab wound is uncommon in accidents.
2- Site of wound: in suicide cut throat, the cut wound is high up in the neck and low down in homicide.
3- Direction of wound: a suicidal stab wound into the heart is directed downward, backwards and inward. While homicidal stabs may take any direction.
4- Number of wounds: multiplicity of wounds suggests homicide or accident.
5- Hesitation marks: (tentative wounds) they are superficial wounds at the beginning of suicidal injuries. They are absent in homicide and in accidents.
6- Foreign body in the wound: broken tip of the knife may be found in the stab wound and help in the identification of the used knife.

Question 39

How can you differentiate between suicidal, homicidal and accidental death? (Examination of the weapon)

Answer 39

1- The presence of weapon: In suicidal cases, the weapon is usually firmly grasped by the victim’s hand and carrying fingerprints of the victim. In homicidal cases, weapon is usually absent, and the assailant in the site of crime to mislead authorities may leave sometimes unused weapon. In an accident, the weapon is present and coincides with the history and circumstances of the accident.
2- Nature of weapon: Suicide choose weapon within his reach, e.g. a soldier may use his own firearm and a butcher may use his knife.
3- Blood or hair on weapon: they must be compared with those of the victim, assailant and suspects.

Question 40

How can you differentiate between suicidal, homicidal and accidental death? (Examination of the suspected assailant (Homicidal))

Answer 40

1- Signs of struggle: assailant clothes are examined for tears or loss of buttons. Also, the body must be examined for abrasions on his face, bites at his hands and their date must coincide with the date of crime.
2- Blood stains on the assailant’s clothes: they must be compared with the victim’s blood group.
3- The fingerprint and the blood group of the assailant must be taken and compared with those found on the victim’s clothes, on the weapon or at the scene of crime.

Question 41

Causes of mechanical asphyxia

Answer 41

Asphyxia is the lack of oxygenation of the tissues due to failure of respiratory processes

1.Impermeable plastic
2.Irresponsible atmosphere
3.Smothering pad.
4.Manual strangulation
5.Ligature strangulation
6.Blocked pharynx/glottis or even trachea
7.Inverted pressure / Pressure on chest

Question 42

Causes of asphyxia

Answer 42

▪ Diseases: e.g., diphtheria.
▪ Poisoning: e.g., morphine (central) or strychnine (peripheral).
▪ Violence → violent asphyxia = mechanical interference with respiration leading to fatal oxygen lack.

Question 43

General signs of asphyxia

Answer 43

A)External signs:
1- Deep blue hypostasis
2- Deep cyanosis
3- Bulging eyes with subconjunctival haemorrhage.
4- Protrusion of tongue.
5- Bloody froth.
B)Internal signs:
1- Congestion of mucous membrane of air passages.
2- Lungs & viscera are congested.
3- Subpleural petechial haemorrhage due to: -
- Anoxia ↑ capillary permeability → blood escape into tissue spaces.
- Mechanical obstruction of venous return of blood →↑capillary pressure to
bursting point.
4- Silvery spots → rupture of air vesicles under pleura (small bright spots).
5- Blood
- Dark (↑ CO2 content)
- Fluid (↑ fibrinolysin)

Question 44

Causes of death in hanging

Answer 44

1- Cerebral anoxia: this occurs due to stretching and narrowing of the carotid arteries.
2- Obstruction of the air passages (asphyxia): usually occurs with typical hanging, due to an upward displacement of the base of the tongue against the posterior pharyngeal wall, occluding the air passage.
3- Sudden cardiac arrest: this may be induced by compression of the carotid sinus and stretching of the vagus, or due to stretching of sympathetic trunks in the neck.
4- Fracture-dislocation of cervical vertebrae: this occurs in judicial hanging which is the method of execution in Egypt, when the body suddenly drops for 2-3 meters and becomes suspended from a noose around the neck, and this result in separation between 2nd, 3rd or 3rd & 4th cervical vertebrae, the upper cervical cord is stretched or torn across, and sometimes the medulla is torn at the border of the pons. Immediate unconsciousness occurs, although heart beats and respiration may continue for p to 10-15 minutes.
5- Delayed death: due to edema of the glottis or acute pulmonary edema, when the victim survived after hanging.

Question 45

Postmortem picture of hanging

Answer 45

A) External signs:
1- External signs of asphyxia (cyanosis, dark blue hypostasis [in the lower limbs, genital organ and may be in the hands], protruded tongue, petechial hemorrhages, bloody froth.
2- Excessive salivation due to pressure of the ligature on the submandibular salivary glands.
3- Ligature mark on the neck: it is due to the pressure of the ligature on the neck, it appears as a pale groove with two thin red lines of congestion or hemorrhage above and below it. The ligature mark of hanging is characterized by the following:
a) Incomplete: It is absent at the point of suspension (in case of fixed noose).
b) Oblique: the highest point of the ligature mark is at the point of suspension.
c) Asymmetrical: the deepest point in the ligature mark is the opposite the point of suspension and tails off and may disappear at the point of suspension.
d) Above the larynx: due to the effect of gravity (i.e. the gravity pull the body downward, causing the ligature to be high up).
4- Hypostasis: in lower limbs, genitalia, lower abdomen, (in postmortem suspension hypostasis simulates suicidal hanging).
B) Internal signs:
1- Internal signs of asphyxia (congestion of the viscera and mucous membranes, dark fluid blood, subpleural petechial hemorrhages…etc.)
2- The hyoid bone may be fractured, if occurred it will be outward fracture due to pressure of the ligature on the ligaments and muscles of the neck.
3- The thyroid cartilage is more susceptible to fracture in hanging.
4- Dissection of the neck shows severe bruising in subcutaneous and deeper tissues, may be rupture of sternomastoid muscles, and the carotid arteries may show transverse tears in the intima.

Question 46

Causes of death in strangulation

Answer 46

1- Asphyxia due to obstruction of the air passage.
2- Reflex cardiac inhibition due to pressure on carotid sinuses.
3- Delayed death may occur from edema of the glottis.

Question 47

Postmortem picture of strangulation

Answer 47

A) External signs:
1- External signs of asphyxia.
2- The ligature mark is characterized by being transverse, symmetrical (the force applied through the ligature is equal all round the neck), complete and usually below the larynx. The mark shows lines of congestion and bruising above and below it in case of anti-mortem strangulation.
3- Signs of resistance e.g., abrasions and bruises on the hands and body.
B) Internal signs:
1- Bruises, congestion, and lacerations of the deeper tissues of the neck at the same level of the ligature mark.
2- Severe congestion of the oropharynx, tonsils, and the root of the tongue above the level of constriction.
3- Fracture of the laryngeal cartilage and may be inward fracture of hyoid bone.

Question 48

Differences between ligature marks of hanging and strangulation

Answer 48

Usually, incomplete VS Complete
Oblique VS Transverse
Asymmetrical VS Symmetrical
Above the larynx VS Usually below the larynx

Question 49

Causes of death in throttling ?

Answer 49

1- Asphyxia due to occlusion of the air passages.
2- Syncope due to pressure on the carotid sinus, resulting in reflex vagal inhibition.
3- Delayed death may occur due to edema of the glottis

Question 50

Post mortem picture of throttling

Answer 50

A) External signs:
1- External signs of asphyxia.
2- Semilunar fingernail abrasions around the neck with bruises, the distribution of the abrasions can tell us whether the assailant right or left-handed when he used single hand for throttling, they can also tell us if he has a missed finger.
N.B.: These signs may be absent if the assailant places a thick towel over the victim’s neck before throttling or the forearm is used instead of hand as in mugging or the assailant’s nails are pared.
3- Signs of resistance e.g., abrasions and bruises on the hands and body.
B) Internal signs:
1- Bruises of the larynx, trachea, supra and infra-hyoid muscles.
2- Inward fracture of hyoid bone (throttling is the most common cause of fracture hyoid bone).
3- Fracture of laryngeal cartilages.

Question 51

Medicolegal importance of examination of hyoid bone

Answer 51

1- Identification of age as the greater cornu unites the body at about 40 years.
2- Differentiation between hanging (outward fracture) and strangulation & throttling (inward fracture).
3- A fracture of hyoid bone must be differentiated from subluxation of the joint between cornu and body (subluxation shows symmetrical and smooth surface with no bruising around but fracture shows asymmetrical with irregular edges and bruising around).
4- In a collection of bones, hyoid bone helps as any other single bone in the body in identification of that collection.

Question 52

Postmortem picture of smothering

Answer 52

A) External signs:
1- External sings of asphyxia.
2- Semilunar fingernail abrasions and bruises around the mouth and nose these abrasions may be absent if a soft pillow is used.
3- Sings of resistance.
B) Internal sings:
1- Bruises and contused wounds on the inner aspect of lips, cheeks and gums.
2- Broken teeth may be seen.

Question 53

External signs of drowning ?

Answer 53

(I) Probable signs:
1- Coolness of the body: the rate of cooling under water is twice the rate of cooling in the air.
2- Goose-skin (Cutis anserina): due to contraction of erector pilae muscles.
3- Washerwoman’s hands: corrugation, paleness and sodden skin of the hands and feet, it occurs 24 hours after submersion.
4- Peeling of the epidermis: the skin of the hands and feet may peel off in the form of gloves due to long submersion. The putrefactive gases which collecting under the skin separate the sodden skin, this occurs after 2 weeks of submersion, the gloves keep the fingerprint of the drowned body, so they facilitate the identification.
5- Hypostasis: involving the upper part of the body (head, shoulders and front of the chest).

(II) Sure sings:
1- Froth from the mouth and nostrils: it is fine, white and odorless, it must be differentiated from the offensive, dark, coarse bubbles of putrefactive froth. The drowning froth is due to mixture of water, air, and mucus during forcible attempts of respiration.
2- Cadaveric spasm: sometimes the victim’s hands are found firmly grasping aquatic weeds, sand, mud, … etc. this indicating that the victim was living before immersion.

Question 54

Internal signs of drowning

Answer 54

1- Air passages:
a) White odorless foam in the respiratory passages.
b) Congested mucosa of the air passages.
c) Presence of foreign bodies (sand, mud, weeds, diatoms, …etc.) in the air passages.
2- Lungs:
a) Pale lungs because water expels blood from the pulmonary capillaries.
b) Over distension and ballooning with rib marks on the surface of the lungs.
c) Tardieu spots and silvery spots on the surface of the lungs.
d) When the lung is cut foam will ooze out from the cut surface.
3- Circulatory system:
a) Obstruction of the pulmonary circulation due to inhalation of water results in distention of the right side of side of the hart and the great veins.
b) More fluid blood in the left side of the heart (hydraemia).
c) Blood chloride imbalance according to whether drowning occurred in salty water (more chloride will be present in the left side of the heart) or in fresh water (less chloride will be present in the left side of the heart).
4- Stomach:
a) Unpalatable water in the stomach (salty or muddy).
b) Foreign bodies such as sand, mud aquatic weeds…etc., may be also found in the stomach.
5- Plankton (diatoms):
They are unicellular organism which may be found in water, may be drawn into the pulmonary capillaries during drowning, and thus may be demonstrated microscopically in the lungs, brain, and kidneys, but the spleen is usually found devoid of plankton because of being contracted in cases of drowning. They are not only a sure sign of drowning, but also can identify the nature of the water in which the body was drowned.

Question 55

Postmortem changes after drowning

Answer 55

1- The rate of cooling of bodies under water is twice as rapid as in case of the bodies in the air.
2- Putrefaction is delayed under water due to low temperature and absence of oxygen; the rate of putrefaction of bodies under water is two times less than that of bodies in the air.
3- Adipocere formation is started in the bodies if it is kept under water for more than 3 weeks.
4- Postmortem wounds in the drowned bodies may be caused by marine animals or by striking to hard objects under water as rocks or propeller of ship.

Question 56

Causes of death of a person fall alive into water

Answer 56

1- Mechanical asphyxia (drowning).
2- Fatal head injury due to striking to a solid object under the water.
3- Reflex vagal inhibition (hydrocution).
4- Hydraemia of the blood with resultant heart failure when drowning occurs in fresh water.