The post below actually is a much simpler explanation (well I think it is anyway).
But I thought for some who like to see diagrams then this would be good, and I have added another few definitions.

External Hemorrhoid
This is where the hemorrhoid starts below the pectinate line (see left)
Internal Hemorrhoid
Where the hemorroid originates above the pectinate line (again see left)
Prolapsed Hemorrhoid
An internal hemorrhoid that has descended below the pectinate line and protrudes outside.
Strangulated Hemorrhoid
This is a prolapsed hemorrhoid whose blood supply has become blocked by constriction of the anal sphincter. (In other words blocked by the tightness of that part of your bottom).
Thrombosed Hemorrhoid
A Hemorrhoid that contains clotted blood.
Hope that helped those of you who were wondering about the differences. As I’ve said before they all hurt like hell regardless of what medical name you give them.
And when you are looking at a proper, complete, effective and long lasting treatment cure for them, they really are all the same in my book.
Thanks for reading.
Tags: external hemorrhoid, internal hemorrhoid, Types of Hemorrhoid