On the origin and the structure of Latin medical adjectives of the coccygeus type

This paper concerns the issue of the length of vowel e in the final -eus of the Latin medical terminological adjectives of coccygeus type. These adjectives are not associated with ancient Latin nouns and do not have a digraphic combination in the Greek prototype at the junction of the noun base and the adjective suffix: anconeus, coccygeus, laryngeus, phalangeus, pharyngeus. The lexemes were created by anatomists between the 16th and 18th centuries, mostly by Jean Riolan the Younger, James Douglas, William Cheselden, Christian H. T. Schreger. The spelling of these words with the final -.us in the work by Douglas in 1707 was a failed (and faulty) attempt to unify the spelling of Latin medical adjectives with a final -eus. The next try belonged to Cheselden (1713): he writes these lexemes with the final -eus. The artificial origin, the presence of two variants of the spelling (-.us and -eus) and of an identical in spelling Latin morpheme (-ĕus), and the simplification of spelling of Latin medical terms are the reasons why different variants of the appearance of the Latin adjectives of coccygeus type exist: with finals -aeus, -ēus, -ĕus. At the same time, an original Latinized Greek adjective existed — coccygius (from κοκκύγιος, used by Pausanias). The author suggests changing the nomenclature spelling of the adjectives of coccygeus type, bringing them in line with the historical “living” appearance: anconius, coccygius, laryngius, phalangius, and pharyngius. Until this change is carried out, it is recommended to consider ⟨e⟩ in the final -eus as a short vowel stressing the antepenultimate syllable.