An inkjet printhead assembly includes an elongate ink supply body. The body defines a plurality of ink supply channels. An elongate cradle defines a plurality of rows of apertures and can be fast with the body so that ink within the ink supply channels can pass through respective rows. A plurality of printhead segments each includes a carrier. Each carrier defines a plurality of rows of ink supply passages arranged so that the ink supply passages can be placed in alignment with respective apertures when the carrier is cradled within the cradle. Each printhead segment further includes an elongate ink ejection printhead mounted to the carrier in fluid communication with the ink supply passages.