Cochleærgren

Cochleærgren is a term encountered in some Nordic-language anatomical writings, used to denote a branch of the cochlear nerve that supplies the cochlea. In standard international anatomy, the structure is described as the cochlear nerve (n. cochlearis), a division of the vestibulocochlear nerve (CN VIII), which carries auditory information from the organ of Corti to the brainstem. There is no universally recognized subdivision named cochleærgren in current Terminologia Anatomica or widely used texts; the term is largely historical or regional and may appear in older literature or localized teaching materials.

When used, cochleærgren is understood as a small, distal branch of the cochlear nerve within the internal auditory canal or the modiolus, contributing to innervation of the cochlear partition. The functional concept is to transmit auditory signals and maintain the cochlea’s tonotopic organization, whereby different frequencies are processed at specific locations along the cochlear spiral.

Developmentally, cochlear nerve fibers arise from spiral ganglion neurons derived from the otic placode; their central axons project to the cochlear nuclei in the brainstem. Clinically, damage to the cochlear nerve, including any informal subdivisions such as a cochleærgren, can contribute to sensorineural hearing loss. Imaging and audiological testing assess the integrity of the cochlear nerve and its connections.

In modern usage, cochlear nerve terminology favors terms such as n. cochlearis and ramus cochlearis or general references to afferents of the organ of Corti, with cochleærgren treated as a nonstandard or historical term.