Facial Nerve (CN VII)

00:01 Cranial nerve VII or the facial nerve is also going to have multiple nuclei reflecting the fact that facial nerve carries out a lot of different types of innovation.

00:13 Here we see the infratemporal course of the facial nerve.

00:18 This is where it's going to go through the internal acoustic meatus along with cranial nerve VIII, as we'll see in a second.

00:26 And it's going to travel through this portion of bone to reach something called the geniculate ganglion.

00:32 At this point, it will go through the facial canal for the most part, to eventually emerge through an opening between the styloid process and the mastoid process called the stylomastoid foramen.

00:45 At the level that geniculate ganglion, it will go off a little tiny branch that's going to form a little anastomosis at the pterygopalatine ganglion with the trigeminal nerve.

00:57 There's also going to be a little tiny branch going off to a very tiny muscle called the stapedius.

01:03 So it's going to be the stapedial nerve.

01:07 There's also a tiny branch that's going to branch off very early called the chorda tympani.

01:12 So called because it's going to pass behind the tympanic membrane to join up with the lingual nerve on its way towards the tongue, where cranial nerve VII can provide some taste sensation to the anterior tongue, as well as parasympathetic innervation of some of the salivary glands.

01:32 The majority of the facial nerve, as we mentioned, will come out the style of mastoid foramen, and it's going to do so right at the level of the parotid gland.

01:43 And it's going to enter in branch essentially within this gland.

01:48 And it's going to give rise to several branches such as the posterior auricular, temporal, zygomatic, buccal, mandibular, and cervical branches.

01:59 It's also going to give rise to branches going off to the gastric muscle, the posterior belly of the digastric muscle and the stylohyoid muscle for which it provides motor innervation.

02:13 In addition to motor innervation, of what's called the muscles of facial expression, there are a lot of visceral efferents and afferents of the facial nerve.

02:24 For example, there's going to be parasympathetic innervation of the lacrimal gland, innervation of the nasal glands, parasympathetic innervation to the sublingual and submandibular glands, as well as special or taste sensation from the anterior two-thirds of the tongue.