Also from the Dryden translation of Plutarch's Life of Sulla:

http://ancienthistory.about.com/library/bl/bl_text_plutarch_sylla.htm
And the very day before his end, it being told him that the magistrate Granius deferred the payment of a public debt, in expectation of his death, he sent for him to his house, and placing his attendants about him, caused him to be strangled; but through the straining of his voice and body, the imposthume breaking, he lost a great quantity of blood. Upon this, his strength failing him, after spending a troublesome night, he died, leaving behind him two young children by Metella. Valeria was afterwards delivered of a daughter, named Posthuma; for so the Romans call those who are born after the father's death.


No relation between imposthume and Posthuma apparently.

A more modern translation (http://makeashorterlink.com/?A28E510C5) gives abscess.


Bingley


Bingley