Postmortem Lividity (Livor Mortis)

Postmortem lividity — also called livor mortis, hypostasis, postmortem staining, suggillation, vibices, or "darnings of death" — is the bluish-purple discolouration of the dependent parts of a dead body caused by the gravitational pooling of stagnant blood after circulation ceases. It is one of the most reliable early postmortem changes and a darling of NEET PG examiners, particularly for its colour in various poisonings and its use in estimating the time since death (TSD) and detecting postmortem displacement of the body.

Definition & basic concept

When the heart stops, blood is no longer propelled through the vasculature. Under gravity, the still-fluid blood (and the red cells it carries) gradually sinks into the dependent, capacious, low-pressure vessels (venules and capillaries) of the lowest parts of the body. The skin overlying these engorged vessels takes on a reddish-blue to purple hue. This is lividity.

Two adjacent terms are tested:

• Hypostasis = the internal counterpart — pooling of blood in the dependent parts of internal organs (lungs, intestinal loops, occipital brain, dependent kidney). Visceral hypostasis can be mistaken for disease (e.g., "hypostatic congestion" of lung bases simulating pneumonia, or posterior gastric wall staining mimicking poisoning).
• Postmortem staining = the external skin discolouration (synonymous with lividity in common usage).

High-yield: Lividity is due to capillo-venous distension by stagnant blood — NOT due to haemorrhage. It is an intravascular phenomenon, which is the key feature distinguishing it from a bruise (contusion), which is extravascular.

Distribution — where it appears and where it does NOT

Lividity develops in the dependent parts, but with one crucial exception: areas subjected to pressure / contact remain pale because the underlying capillaries are compressed and cannot fill with blood. This pattern of contact pallor is itself an examination point.

• In a body lying supine (most common): lividity appears over the back, nape of neck, buttocks, and back of limbs. It is absent over the scapulae, buttocks (ischial tuberosities), shoulder blades, calves, and any part pressing against the floor, and absent under tight clothing (collar, belt, bra straps → "white line" / pressure marks).
• In a body lying prone: lividity is seen over the face, front of chest and abdomen.
• In hanging (vertical suspension): lividity gravitates to the lower limbs (feet, legs), forearms, and hands, and the genitals — the classic "glove and stocking" distribution. This is a frequently asked fact.
• In drowning: lividity is often over the head, neck, and upper chest because the body tends to float face-down with the head dependent.

High-yield: Pressure pallor over the buttocks and shoulder blades in a supine body, and the "glove-and-stocking" pattern in hanging, are favourite single-best-answer cues.

Time course — appearance, fixation & medicolegal value

The timing is the single most examined quantitative aspect. Memorise the sequence.

Stage	Time after death	Feature
First appears	30 min – 1 hour (commonly quoted)	Faint mottled patches
Becomes confluent / well-developed	4 hours	Distinct, deep colour
Maximum / fully developed	6 – 8 hours	Deepest intensity
Fixation begins	~6 hours	Stain no longer fully shifts
Fixation complete	8 – 12 hours (up to 12)	Colour permanent on pressure & repositioning

Two practical tests examiners love:

1. Blanching on thumb pressure — Before fixation, firm pressure with the thumb empties the distended capillaries and the spot blanches (turns pale), returning to colour when released. After fixation, pressure does not blanch.
2. Shifting on repositioning — If the body is turned within the first ~6 hours, lividity shifts to the new dependent area. Between ~6–12 hours, the original lividity persists and secondary (new) lividity also develops in the new dependent area → dual lividity. After ~12 hours, lividity is fixed and does not shift.

High-yield: Lividity that does NOT correspond to the body's current position = the body was moved after death (after fixation). This is the cornerstone of using livor mortis to detect postmortem displacement.

Why fixation occurs: Two mechanisms are described — (a) rupture/leakage of stagnant blood out of distended, autolysing capillaries into surrounding tissue, and (b) early postmortem clotting and increasing blood viscosity preventing the blood from shifting. The older "fixation = vessels rupture" explanation is the classically taught one.

Stepwise medicolegal interpretation of livor

Approach: Inspect distribution → press with thumb (blanches? → < 6 h; no blanch? → fixed, > 8–12 h) → note pressure pallor pattern → compare lividity site with body position → mismatch → body was moved.

Colour of lividity — the highest-yield table

The colour of postmortem lividity points to the cause of death / poison. This is asked almost every year. Learn it cold.

Colour of lividity	Cause / Mechanism
Bluish-purple / blue-violet	Normal (deoxygenated venous blood)
Cherry-red / bright pink	Carbon monoxide (CO) poisoning — carboxyhaemoglobin (COHb)
Bright cherry-red / pink	Cyanide (HCN) poisoning — cytochrome oxidase blocked → blood stays oxygenated (oxyHb)
Bright red / pink	Cold exposure / hypothermia and refrigeration of the body (re-oxygenation through skin); also bodies kept in a fridge
Cherry-pink/red	Drowning (cold water + dilution)
Chocolate-brown / brownish	Methaemoglobinaemia — nitrites, nitrates, potassium chlorate, aniline, nitrobenzene, phenacetin
Bronze / brownish-bronze	Clostridium perfringens septicaemia
Dark / deep blue (markedly)	Asphyxial deaths (hanging, strangulation, suffocation), congestion
Greenish	Hydrogen sulphide (H₂S) poisoning — sulphaemoglobin; also early decomposition

High-yield: Both CO and cyanide give a cherry-red lividity — but CO is the classic "cherry-red," while cyanide gives a bright pink/brick-red hue (blood remains arterialised because tissues cannot use oxygen). Cold storage/refrigeration also turns lividity pink/red and can mimic CO — a known trap.

High-yield: Chocolate-brown lividity → think methaemoglobinaemia (nitrites, nitrobenzene, aniline, potassium chlorate, dapsone).

Mnemonic for cherry-red lividity — "Cherry pickers Catch Cold Cyanide & CO": Cold/refrigeration, Cyanide, Carbon monoxide all give cherry-red/pink.

Lividity vs Bruise (contusion) — must-know differential

Differentiating postmortem lividity from an antemortem bruise is a perennial question because both look like bluish discolouration.

Feature	Postmortem Lividity	Bruise (Contusion)
Location	Dependent parts	Anywhere (site of impact)
Margin	Diffuse, ill-defined	Well-defined, can be patterned
Elevation	Not raised	Often swollen/raised
Blood location	Intravascular (in vessels)	Extravascular (in tissues)
On incision	Blood washes away with water; vessels engorged	Clotted blood in tissues; does not wash away
Pressure (early)	Blanches	Does not blanch
Epidermal damage	Absent	May be present
Colour change over time	Static (until decomposition)	Goes through bruise colour sequence
Tissue reaction	None	Vital reaction (if antemortem) — extravasation, later haemosiderin

High-yield: The decisive bedside test — incise the discoloured area and wash with water. Lividity blood is intravascular and washes off; contusion blood is in the tissues (clotted) and persists.

Lividity vs Decomposition staining

Early decomposition gives a greenish discolouration starting in the right iliac fossa (over the caecum), spreading as marbling. Do not confuse this greenish hue with the greenish lividity of H₂S poisoning; the location and accompanying putrefactive signs (bloating, foul smell, marbling of superficial veins) distinguish decomposition.

Postmortem (Tardieu) spots

When lividity is intense and prolonged (especially in hanging / dependent limbs), capillaries rupture, producing petechial haemorrhages in the dependent skin called Tardieu spots. These are seen on the lower legs/feet in hanging and must not be mistaken for antemortem petechiae of asphyxia.

High-yield: Tardieu spots = postmortem petechial haemorrhages of hypostasis, classically in the legs of a hanging victim; eponym worth remembering.

Factors affecting lividity

• Volume & fluidity of blood — copious in deaths with fluid blood (asphyxia, sudden death); scanty and faint in severe haemorrhage, anaemia, and exsanguination (lividity may be feeble/almost absent).
• Mode of death — deep and rapid in asphyxia and congestive cardiac failure; delayed and patchy in haemorrhagic deaths.
• Skin colour — masked in deeply pigmented individuals.
• Posture / clothing — determine distribution and pressure pallor.

Time since death (TSD) — putting it together

Lividity contributes to early TSD estimation when combined with rigor mortis and algor mortis (body cooling):

Rule of thumb: Lividity beginning → ~1 h; well-developed/confluent → ~4 h; maximum and starting to fix → ~6 h; fixed → 8–12 h.

High-yield: A body found supine but with fixed lividity on the front = body lay prone for the first several hours after death and was then turned supine after fixation → strong evidence of body movement and possible scene tampering.

Clinical / forensic significance — quick summary

1. A sure sign of death (early changes group, with cooling & rigor).
2. Estimates time since death (appearance, intensity, fixation).
3. Indicates body posture / position at and after death.
4. Detects movement of the body after death (mismatched or dual lividity).
5. Suggests the cause of death / poison by its colour.
6. May reveal pressure pallor patterns (ligature, clothing, surface objects).

Complications / pitfalls in interpretation

• Refrigeration trap: Bodies stored in a mortuary fridge develop pink lividity — do not over-call CO poisoning; confirm with blood COHb level (saturation > 50% is fatal; symptoms from ~ 20–30%).
• Visceral hypostasis can simulate disease (hypostatic pneumonia, gastric "poisoning" staining, subendocardial-looking congestion).
• Faint/absent lividity in exsanguination may be misread as a long postmortem interval.
• Tardieu spots may be mistaken for antemortem traumatic petechiae.

Key differentials at a glance

→ Lividity vs bruise (intravascular vs extravascular; washes off vs persists). → Lividity vs decomposition green (dependent purple vs RIF green + putrefaction). → Cherry-red of CO vs cyanide vs cold storage (history + COHb level + smell of bitter almonds in cyanide). → Hypostatic congestion vs true pneumonia/poisoning in viscera.

Recently asked / exam angle

NEET PG, INI-CET and FMGE consistently test:

• Colour of lividity in poisoning — single most common stem. "Cherry-red lividity → CO"; "chocolate/brown lividity → nitrite/nitrobenzene/methaemoglobinaemia"; "bright pink + bitter almond smell → cyanide"; "greenish → H₂S."
• Fixation timing — "Lividity becomes fixed in how many hours?" → 6–12 h (does not shift after ~12 h; thumb pressure no longer blanches).
• Lividity vs contusion — incision + wash-off test; intravascular vs extravascular.
• Distribution in hanging — feet, legs, hands ("glove and stocking"); Tardieu spots on legs.
• Pressure pallor — pale areas over buttocks/scapulae in supine bodies; contact flattening.
• Body displacement — mismatch between lividity site and current position = body moved after death.
• Eponyms/terms — "Tardieu spots," "vibices," "suggillation," "postmortem staining."
• Trap question — refrigerated body with pink lividity should not be misattributed to CO without COHb confirmation.

Rapid revision

• Livor mortis = gravitational pooling of stagnant blood in dependent parts; intravascular, not haemorrhage.
• Appears 30 min–1 h, confluent by 4 h, maximum 6–8 h, fixed 8–12 h.
• Before fixation it blanches on pressure and shifts on repositioning; after fixation it does neither.
• Contact/pressure areas stay pale (buttocks, scapulae, ligature/clothing marks).
• Hanging → glove-and-stocking lividity on legs, feet, forearms; Tardieu spots = postmortem petechiae of the legs.
• Cherry-red lividity → carbon monoxide (COHb); also cold/refrigeration mimic.
• Bright pink/brick-red + bitter-almond smell → cyanide.
• Chocolate-brown lividity → methaemoglobinaemia (nitrites, nitrobenzene, aniline, potassium chlorate).
• Greenish → H₂S (sulphaemoglobin) — distinguish from RIF green of decomposition.
• Bronze → Clostridium perfringens septicaemia.
• Lividity vs bruise: incise + wash — lividity washes off, bruise (clotted, extravascular) persists.
• Lividity mismatched with body position = body moved after death; dual lividity if moved at 6–12 h.
• Lividity is faint/absent in exsanguination, anaemia, deep haemorrhage.
• It is an early, sure sign of death used for TSD, posture, displacement, and cause of death.