Question

A doctor at autopsy noticed the following finding on a cadaver (image showing marbling -- greenish-black discolouration over superficial veins of the skin). Which of the following is true regarding this finding?

• A. It is due to sulphaemoglobin pigment
• B. This change is seen at 24 hours
• C. It is non bacterial
• D. It is associated with lightning case

Hint:

Marbling follows the course of superficial veins due to a pigment formed by bacterial action on haemoglobin.

Answer 1

The Correct Option is A

Postmortem changes -- marbling:
Definition: Greenish-black/brownish network of discolouration along superficial veins, giving a marble-like appearance.

Mechanism:
- Putrefactive bacteria (gut flora) produce $\text{H}_2\text{S}$.
- $\text{H}_2\text{S}$ + haemoglobin (released by haemolysis) --> $\text{sulphaemoglobin}$ (greenish-black).
- This pigment diffuses into and stains the walls of superficial blood vessels.

Timeline:
- Onset: ~24 hours after death (internally).
- Naked-eye visibility: 36--48 hours after death.

Option analysis:
A -- Sulphaemoglobin pigment: CORRECT.
B -- Seen at 24 hours: Incorrect (visible at 36--48 h).
C -- Non-bacterial: Incorrect (bacterial H2S is the cause).
D -- Lightning: Incorrect (lightning causes Lichtenberg figures).
\[\boxed{\text{It is due to sulphaemoglobin pigment}}\]