Pulvino

right|thumb|250px|Pulvino in the Basilica of San Vitale A pulvino (or impost block) is an architectural structural element (dosseret) having the shape of an inverted pyramid cushion, which is placed between the column capital and the arch base.

==Overview== Usually decorated with fretwork or relief ornamental motifs, the pulvino reaches its maximum expression in the Byzantine architecture; some examples can be found in the early Christian architecture of Ravenna. Its particular convex shape gives the pulvino the structural function of concentrating the tensions generated by the loads above it and passing the tensions on the column located below the capital. An example can be seen in the church of San Lorenzo in Florence designed by Filippo Brunelleschi around 1420. There he resorted to additional segments of entablature improperly defined as "Brunelleschian nut". The pulvino in this case created a balanced entablature, on which the round arches are set.