Highmore, Nathaniel (1613–1685), British surgeon. Highmore is remembered for his studies in anatomy. In 1651 he published a treatise on human anatomy that was noteworthy for its sound treatment of the circulation of the blood. This treatise also contains his description of the air cavity of the maxilla, now known as the maxillary sinus or antrum of Highmore. The cavity had been discovered previously and had actually been illustrated by Leonardo da Vinci. Highmore is also known for his description of the incomplete partition that divides the scrotum into two sacs each containing a testis.