Rhodius (loc. cit.) says the hemispathion is a small variety of the spathion.
An instrument in the Louvre has two blades of this shape at either end of a round handle ornamented with rolling grooves ([Pl. VIII, fig. 8]).
Polypus Knife.
Greek, πολυπικὸν σπαθίον, πολυποδικὸν σπαθίον; Latin, ferramentum acutum modo spathae factum.
Paulus Aegineta (VI. xxv) thus describes the excision of nasal polypus:
‘Holding in his right hand the polypus scalpel, which is shaped like a myrtle leaf and sharp pointed (πολυπικῷ σπαθίῳ τῷ μυρσινοειδεῖ ἀκμαίῳ), we cut round the polypus or fleshy tumour, applying the point of the steel blade (τὴν ἀκμὴν τοῦ σιδήρου) to the part where it adheres to the nose. Afterwards turning the instrument end for end (ἀντιστρέψαντες) we bring out the separated fleshy body with the scoop’ (τῷ κυαθίσκῳ).
This description reminds us very forcibly of Celsus’s account of the operation:
Ferramento acuto modo spathae facto, resolvere ab osse oportet. Ubi abscissus est unco ferramento extrahendus est (VII. x).
These passages, especially that from Paul, show that like the majority of Roman instruments the polypus scalpel was a double instrument, with a sharp-pointed leaf-shaped blade at one end and a scoop at the other. The fact that it was able to work inside the nose shows that it could not have been of any great breadth. Paul says it was able to be used in the auditory canal.
‘If there be a fleshy excrescence it may be excised with a pterygium knife or the polypus scalpel’ (VI. xxiv).