Pore: Simple perforation of any skeletal structure. Pore diameter is greater than thickness of the structure.
Carcass: Part of wall on intervallum side.
OW: Outer wall.
SW: Single wall.
Regular repartition: Pores covered the whole wall.
Irregular repartition: Pores covering partially the wall.
Vertical intervallar structures: Longitudinal and often radial structures inside the intervallum (septa, taeniae...).
Intervallum: Space enclosed between the walls.
Carcass perforations: outer wall or single wall (OW/SW) | |_ Repartition of carcass pores (OW/SW) | |_ Repartition types of carcass pores (OW/SW) {Irregular repartition , Independant from the vertical intervallar structures , isn't included in the term}