Deep Structures of the Neck

00:01 Now let's take a look at some of the deeper structures of the neck.

00:06 Let's go back to a cross section view where we can again find the carotid sheath contents.

00:12 We have the internal jugular vein a bit laterally compared to the common carotid artery, which is a bit more medial.

00:20 And then we also have the vagus nerve or cranial nerve 10.

00:24 Again, these are all encased in something called the carotid sheath.

00:28 And together we call that the vascular compartment.

00:33 Here we see the internal jugular vein because we've removed the sternocleidomastoid.

00:39 We also see the common carotid artery and the vagus nerve.

00:45 In terms of the carotid, we have the common carotid traveling upward and eventually branching into two or bifurcating.

00:53 It will continue on as the internal carotid into the cranial cavity to provide blood supply to cranial structures such as the brain.

01:02 And right as it does so.

01:04 It forms this widen area called the carotid sinus, which is where we find baroreceptors, which are receptors sensing pressure in the blood.

01:15 We also have the external carotid at this bifurcation point, and that's going to give a lot of branches that will supply the head and neck, such as the superior thyroid artery.

01:29 Further down we see the subclavian artery and its thyrocervical trunk, which is where we find the inferior thyroid artery.

01:41 In terms of veins here we see the internal jugular vein joining with the subclavian vein to form the brachiocephalic vein.

01:50 And we have a similar vein on the left.

01:52 The left brachiocephalic vein.

01:54 Due to the asymmetry of the heart, the left brachiocephalic vein really crosses midline to reach the right side of the heart where the superior vena cava is.

02:04 Therefore, it also mostly crosses over the trachea.

02:08 We also have the cricoid cartilage, and the thyroid cartilage of the larynx.

02:15 Most superiorly we have the hyoid bone to which many muscles attach.

02:22 Sitting here on the trachea is the thyroid gland.

02:26 And it has lateral lobes on either side right and left.

02:29 In the midline a variable pyramidal lobe that point superiorly and in between connecting the lateral lobes is something called the isthmus.

02:41 Here we see superior thyroid veins and middle thyroid veins as well as inferior thyroid veins.

02:51 The superior and middle draining into the internal jugular while the inferior tending to drain into the brachiocephalic.

02:58 And that's in contrast to the arteries, where we only mentioned to where we had the superior thyroid artery coming off the external carotid and the inferior thyroid coming off of the subclavian.