A rainwater trench known as the cunette ran down the centre of the dry ditch, parallel to the walls. The side of the ditch opposite the scarp, known as the contra scarpa or counterscarp, was in most cases revetted. Above this was the covered way, a passage on the top of the couterscarp along which the defenders could manoeuvre while protected from the enemy by an embankment.

Troops reached the ditch by means of sally ports, specially designed vaulted passages running from the piazze basse in the bastion flanks.