Sublingual Region

00:01 The next region we'll look at is the area under the tongue or what we call the sublingual region.

00:09 So here we see the intrinsic muscles of the tongue sitting on the superior aspect of the tongue.

00:17 We also see some of the oral mucosa or the mucosa that lines the oral cavity.

00:23 Medially, we see one of those extrinsic tongue muscles, the genioglossus.

00:29 As well as the geniohyoid, one of the suprahyoid muscles.

00:35 In the inferior lateral aspect, we see the wide flat muscle that we call the mylohyoid muscle.

00:42 And then anteriorly, we have the mandible.

00:47 Posteriorly, we have communications with the submandibular and parapharyngeal spaces.

00:56 In terms of contents of the sublingual region, we see the hyoglossus muscle, which is very closely related to one of our salivary glands, the submandibular gland.

01:12 We see the submandibular gland has this duct to carry its contents out to the oral cavity called the submandibular duct.

01:23 And this submandibular gland is sort of pinching around that other muscle we saw that has a very wide flat shape called the mylohyoid.

01:33 And then beyond that, we have our smaller sublingual gland which is directly under the tongue.

01:40 And there are sublingual ducts that enter directly into the oral cavity.

01:45 And then some of the other ones will join the submandibular duct on its way into the opening of the oral cavity.

01:52 We also have the lingual nerve, which is that branch of the mandibular nerve or cranial nerve V3 coming down to supply the tongue.

02:05 From sort of a posterior lateral view, we can see a different aspect of the submandibular gland here and we can see just how closely it is associated to that mylohyoid, sort of wrapping around the mylohyoid.

02:20 We also see the lingual nerve coming down and innervating the tongue, we see the submandibular duct making its way towards the oral cavity to deliver saliva.

02:31 And then the sublingual gland, which is again a bit smaller than the submandibular gland but located more directly underneath the tongue.

02:40 Here we see the common carotid branching into the external carotid while the internal carotid makes its way to the cranial cavity.

02:49 One of those branches of the external carotid is the lingual artery, which we can see here traveling past the hyoglossus muscle.

02:58 We have the dorsal lingual branch and sublingual branch, as well as the deep lingual branch.

03:07 We also have venous drainage in this area that pretty much mirrors the arterial supply.

03:14 And we see it's coming back to the lingual vein on its way to the common facial vein and eventually into the internal jugular.

03:24 Although there's variation in this area in terms of whether it's all passing deep two or lateral two the hyoglossus muscle.

03:33 In terms of nerves, here's where we see the hypoglossal nerve or cranial nerve XII.

03:40 More superiorly is where we see the lingual nerve or cranial nerve V3.

03:47 And it's coming from a more superior aspect because it actually parallels the inferior alveolar nerve that was coming through the mandibular foramen or canal.

03:57 It also forms a little ganglion here called the submandibular ganglion.

04:04 Now the submandibular ganglion is another area where the cranial nerve VII is hitching a ride with the lingual nerve.

04:13 So here we see the lingual nerve coming down and those fibers that are being provided by cranial nerve V3 are providing general sensation to the tongue.

04:25 But via this little shortcut called the chorda tympani, some branches of cranial nerve VII will join the lingual nerve.

04:33 On its way to provide taste sensation to the anterior two thirds of the tongue.

04:38 But it's also going to provide some autonomic innervation, specifically the preganglionic fibers of parasympathetic fibers are going to go towards the submandibular ganglion.

04:52 And then from there, there are going to be branches that are going to supply the sublingual gland and the submandibular gland.

05:00 And in this way cranial nerve VII, again pretty much hitches a ride to carry out its functions in this area, namely taste sensation to the anterior two thirds of the tongue and parasympathetic innervation to the sublingual and submandibular salivary glands.