Of transverse presentations, Celsus says:
Remedio est cervix praecisa; ut separatim utraque pars auferatur. Id unco fit, qui, priori similis, in interiore tantum parte per totam aciem exacuitur. Tum id agendum est ut ante caput deinde reliqua pars auferatur.
‘The treatment is to divide the neck so that each part may be extracted separately. This is done with a hook which, though similar to the last, is sharpened on its inside only, along its whole border. Then we must endeavour to bring away the head first, and then the rest of the body.’
Decapitation has now given way before Caesarean section; but the decapitator, little altered since the days of Celsus, still finds a place in surgical instrument catalogues.
Paul and Aetius both mention division at the neck, but do not describe a special instrument. A ring knife for dismembering the foetus has already been discussed among the cutting instruments; but this seems to be a different variety with a handle, which it is convenient to discuss in proximity to the embryo hook. [Pl. L, fig. 2] shows a knife on this principle in the Bibliothèque Nationale.
Cranioclast.
Greek, πίεστρον, ἐμβρυοθλάστης, θλάστης;
The cranioclast is mentioned by Hippocrates (ii. 701).
Σχίσαντα τὴν κεφαλὴν μαχαιρίῳ ξυμπλάσαι ἵνα μὴ θραύσῃ τῷ πιέστρῳ καὶ τὰ ὀστέα ἕλκειν τῷ ὀστεουλκῷ.
‘Opening the head with a scalpel, break it up with the cranioclast in such a way as not to splinter it into fragments, and remove the bones with a bone forceps.’