From here three bundles emerge: superior and inferior division of the vestibular nerve and the nerve from the posterior semicircular canal (see article: vestibulocochlear nerve (CN VIII) for further details). In addition to the three nerves which enter it, it also contains the vestibular ganglion ( ganglion of Scarpa). See mnemonic for the position of the nerves in the IAC.
inferior: cochlear nerve and inferior vestibular nerve (IVN) the cochlear nerve is situated anteriorly. superior: facial nerve and superior vestibular nerve (SVN) the facial nerve is anterior to the SVN and is separated from it laterally by Bill's bar, a vertical ridge of bone. This horizontal ridge divides the canal into superior and inferior portions: Their position is most constant in the lateral portion of the meatus which is anatomically divided by the falciform crescent. superior vestibular nerve (component of CN VIII). in length if measured from the tragus from the bottom of the concha its length is about 2.5 cm. inferior vestibular nerve (component of CN VIII) The External Acoustic Meatus (meatus acusticus externus external auditory canal or meatus) extends from the bottom of the concha to the tympanic membrane. facial motor root (motor component of CN VII). 
nervus intermedius (sensory component of CN VII). There are five nerves that run through the IAM: labyrinthine artery (usually a branch of the AICA or basilar artery) Porus acusticus internus / Vstup vnitního zvukovodu Meatus acusticus internus / Vnitní zvukovod Fossa subarcuata Apertura externa canaliculi vestibuli Canaliculus vestibuli / Pedsíový kanálek Margo posterior partis petrosae Sulcus sinus petrosi inferioris. 
The canal narrows laterally, and the lateral boundary is the fundus, where the canal splits into three distinct openings, one of which is the facial nerve canal. The margins of the opening are smooth and rounded, and the canal is short (1 cm), running laterally to the bone. The opening of the IAM, the porus acusticus internus, is located within the cranial cavity, near the posterior surface of the temporal bone.
The internal acoustic canal (IAC), also known as the internal auditory canal or meatus ( IAM), is a bony canal within the petrous portion of the temporal bone that transmits nerves and vessels from within the posterior cranial fossa to the auditory and vestibular apparatus.
0 kommentar(er)
