opening of internal acoustic meatus

internal acoustic opening

[TA]
the inner opening of the internal acoustic meatus on the posterior surface of the petrous part of the temporal bone.

o·pen·ing of in·ter·nal a·cous·tic me·a·tus

(ō'pĕn-ing in-tĕr'năl ă-kūs'tik mē-ā'tŭs)
The inner opening of the internal acoustic meatus on the posterior surface of the petrous part of the temporal bone.