Neck Anatomy – Organisation of the Neck – Part 1

So this is a tutorial on the organization
of the neck. I’m going to talk a little bit about the anatomical triangles of the neck,
the anterior and posterior triangles. And then I’ll go on to talk about the fascial
compartments. I’ll also talk a little bit about the different structures that pass through
the anatomical triangles, but I’ll go on to more detail on other tutorials on this. So we’re looking at an anterior view of the
neck. You can see this thin muscle here. This is the platysma muscle. This is contained
in the superficial fascia of the neck. So I’ll get rid of these and show you the different
triangles. If I just zoom a little bit more, I got rid
of the platysma muscle, which lies in the superficial fascia and then you can see this
big muscle here, which runs from the mastoid process down to attach onto the sternum and
also onto the clavicle. So it’s got two attachments, a sternal and a clavicular attachment, then
it’s also attached to the mastoid process up here. So this is the sternocleidomastoid
muscle named because of its attachments. The anterior triangle of the neck is defined
by few boundaries — the inferior border of the mandible forms the superior border of
the triangle, the midline forms the medial border and the anterior border of the sternocleidomastoid
muscle forms the lateral border of the triangle. So the triangle is this here, the midline,
inferior surface of the mandible. So you’ve got the inferior surface of the
mandible forming the superior border. You’ve got the anterior border of the sternocleidomastoid
forming the lateral border and the midline of the neck which runs right down here forms
the medial border. So that’s the anterior triangle of the neck. So as you can see here, there are several
structures which run in the anterior triangle of the neck. I won’t go into huge detail on
what these are, but I’ll just quickly go through them. You can see this bone here. This is the hyoid
bone. This bone is important because it forms the attachment for many muscles which make
up the floor of the mouth and it provides attachments for the tongue muscles and it’s
involved in swallowing. So this is the hyoid bone here. Muscles above it are called the suprahyoid
muscles and these run in the anterior triangle. And you’ve got these muscles below the hyoid
bone, so these are the infrahyoid muscles. These infrahyoid muscles are also called strap
muscles because of their appearance. I guess they look like a strap, so these are the strap
muscles. Below the strap muscles, we’ve got the thyroid
gland. We’ve got the larynx here and the trachea. We’ve also got the parathyroid glands behind
the thyroid. And then also, you’ve got these vessels, which
obviously run in the anterior triangle. You’ve got the common carotid and its branches, so
the external and internal carotid. You’ve got the internal jugular vein running through
the anterior triangle. And then you’ve also got nerves. So for instance, the vagus nerve
and recurrent laryngeal nerves run through the anterior triangle. That’s the anterior triangle. Just to recap,
it’s formed by the anterior border of the sternocleidomastoid, the inferior margin of
the mandible and the midline of the neck. So the posterior triangle lies just behind
the anterior triangle. It’s formed by the posterior border of the sternocleidomastoid,
the middle portion of the clavicle and the anterior border of the trapezius muscle, this
big muscle at the back (the big, powerful muscle there). The apex of the posterior triangle is this
bit of occipital bone just behind the mastoid process here. You can see the triangle formed
by the anterior margin of the trapezius, the middle portion of the clavicle and then the
posterior border of the sternocleidomastoid with its apex just behind the mastoid process. So again, the posterior triangle of the neck
contains a lot of important structures. I’m not going to go through all of them, but just
a few so…


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