unit 1.3: postmortem changes

Postmortem changes

refers to a continuum of changes that occur in a dead body following death

Algor Mortis

* Cold Death
* **First demonstrable change** after death is cooling of the body
* **Not a reliable indicator** as to the time of death due to the different temperature of the environment

2 to 2.5 deg F/hr

### Algor Mortis

1st hour

1\.5 to 2 deg F/hr

### Algor Mortis

next 12hrs

1 deg F /hr

### Algor Mortis

next 12-18hrs

Rigor Mortis

**Rigidity** of the body due to **hardening of the skeletal muscles** caused by a series of physiochemical events after death

formation of **locking-chemical bridges between actin & myosin**

### Rigor Mortis

**Lack of ATP** regeneration and increased **lactic** **acidity**

energy dependent breakage of sarcomere contraction

### Rigor Mortis

the glycogen stores are rapidly depleted, preventing ___

Sets **within 2 hrs after** death

### Rigor Mortis

head & neck → small muscles → larger muscles

6-12 hrs

### Rigor Mortis

complete and fully fixed

36-48 hours

### Rigor Mortis

Dissipates

Anti-gravitational Rigor Mortis

### Rigor Mortis

Fixed rigor mortis of the **upper extremities wherein the arms are suspended against gravity** indicating they were previously held in that position during time of death

Livor Mortis or Postmortem hypostasis

* **Blood supply gravitates to the skin vessels** which become toneless and dilate after circulation ceases
* **deep purple-red discoloration** in the skin

Blanching

### Livor Mortis

occurs in gravity dependent areas of the body that come into contact with firm surfaces

20 min after death

### Livor Mortis

Becomes evident as early as ___

Erythrocyte Sedimentation Rate

### Livor Mortis

rate of settling of red blood cells

within 4 hrs

### Livor Mortis

Fully evident

8 - 12 hrs

### Livor Mortis

fixed

Lividity

### Livor Mortis

* Blood settles down in the lowest elevation of the body
* **pink to purple** discoloration
* **blood pooling** in dependent areas of the body

Tardieu Spots

### Livor Mortis

* Auguste Ambroise Tardieu
* **ecchymoses**; subpleural spots of ecchymosis that follow the **death of a newborn child by strangulation or suffocation**
* **purple to black** spots
* rupture of capillaries

Tache noir de la sclerotique

* After death, the **skin and mucosal membranes may desiccate** resulting in a change in color and character of these tissues
* horizontal linear **scleral blackening** along the equator of the globe of the **eye**
* sclera is exposed to drying when the eyelids are incompletely shut
* initially red in appearance and over time becomes black
* **Lips, tip of tongue and scrotum** darken with postmortem drying

mastoid-to-mastoid incision

### Techniques for Autopsy

scalp

I-incision

### Techniques for Autopsy: *Trunk*

straight line incision from chin to pubic symphysis

Y-incision

### Techniques for Autopsy: *Trunk*

starts from the acromion and meets at the xiphoid process and continues up to the pubic symphysis

Modified Y-incision

### Techniques for Autopsy: *Trunk*

made from suprasternal notch to symphysis then extends over clavicle to its center on both sides and passes upwards over neck and behind the ear

To expose:


1. chambers of the Heart
2. inner lungs
3. inner liver
4. urinary bladder cavity
5. GIT lumen

Purposes of Opening Up

Technique of Virchow

### Conventional Techniques for Autopsy

organs removed and dissected **individually**

head → thoracic → abdominal organs

### Conventional Techniques for Autopsy: *Virchow*

order of examination

Technique of Rokitansky

### Conventional Techniques for Autopsy

* **in-situ dissection** in part combined with en bloc-technique
* analysis/study **on site**

Technique of Ghon

### Conventional Techniques for Autopsy

* **en bloc** Technique - only get a portion

Technique of Letulle

### Conventional Techniques for Autopsy

* **en masse** Technique - complete removal

Needle Autopsy

### Conventional Techniques for Autopsy: *Minimally Invasive*

get a sample using a needle

blind biopsies

### Conventional Techniques for Autopsy: *Minimally Invasive*

Multiple percutaneous needle biopsies after death

**Laparoscopic** (abdominal) and **thoracoscopic** (chest)

### Conventional Techniques for Autopsy: *Minimally Invasive*

investigation with tissue sampling

Mini-autopsy

### Conventional Techniques for Autopsy: *Minimally Invasive*

extensive organ sampling or removal via a **limited incision**

CT and MRI

### Conventional Techniques for Autopsy: *Imaging Autopsies*

red vessels, areas with mass, areas with blockage, etc.

3 months after final report

### Suggested Material Retention: *Non-Forensic*

Wet Tissue

10 years

### Suggested Material Retention: *Non-Forensic*

Paraffin blocks, Slides, Reports

3 years

### Suggested Material Retention: *Forensic*

Wet Tissue

indefinitely

### Suggested Material Retention: *Forensic*

Paraffin blocks, Slides, Reports, Gross Photos, Dried Blood stain or frozen tissue for DNA

1 year

### Suggested Material Retention: *Forensic*

Body Fluids & Tissues for Toxicology

**Liver**: 1500-1800gm

heaviest human organ

**Ovary**: 5-7gm

lightest human organ

Right atrium

thinnest heart blah

Left ventricle

thickest heart blah