**Core Concept**
Haemostasis in scalp wounds is a complex process involving the interaction of various factors, including platelets, coagulation factors, and the scalp's unique anatomy. The scalp has a rich vascular supply and a loose, fibrous structure that can make haemostasis challenging to achieve.

**Why the Correct Answer is Right**
The correct answer is **Epsom salt** (Magnesium sulfate), which is used to promote haemostasis in scalp wounds by inducing vasoconstriction and reducing bleeding. The application of Epsom salt helps to constrict blood vessels, thereby reducing blood flow and promoting clotting. This is particularly useful in scalp wounds where bleeding can be difficult to control.

**Why Each Wrong Option is Incorrect**
**Option A:** **Pressure bandage** is a general method for controlling bleeding, but it may not be effective in scalp wounds due to the rich vascular supply and loose structure of the scalp.
**Option B:** **Topical haemostatic agents** such as thrombin or fibrinogen may not be as effective in scalp wounds as Epsom salt, which has a more direct effect on vasoconstriction.
**Option C:** **Tourniquet** application is not recommended for scalp wounds due to the risk of nerve damage and ischemia.

**Clinical Pearl / High-Yield Fact**
It's essential to note that Epsom salt is not a substitute for proper wound care and may require additional measures to promote healing.

**Correct Answer:** E. Epsom salt