Adnexa is a general term that refers to the accessory structures of an organ.
Adnexa have been described with:
- cutaneous/skin adnexa
- hair follicles, sweat glands, nails
- adnexa mastoidea
- structures in the mastoid (posterior) wall of the middle ear, e.g. mastoid antrum, aditus ad antrum, mastoid air cells
- adnexa oculi
- eyelids, lacrimal apparatus
- adnexa uteri (uterus)
In general radiological use, the term is often (incorrectly) used synonymously with the ovary, an adnexal structure of the uterus.
It is an unusual word (for English-speakers) as it has an identical spelling and pronunciation whether used in a singular or plural sense. Therefore the terms 'adnexus/adnexum' for a single adnexa or 'adnexae' for more than one adnexa are incorrect, and should not be used.
The adjectival form for adnexa is adnexal. The term adnexitis is sometimes used for an inflammation of the adnexa uteri.
History and etymology
"Adnexa" derives from the Latin adnectere ("to tie together").