...we've got the levator scapulae, which elevates the scapula, runs through the posterior triangle.
You've got scalene muscles which attach to the ribs and originates on the transverse
process of the cervical vertebra.
They're not shown in here, but they're accessory muscles of respiration.
And then you've got vessels.
So you can see the subclavian vein and artery running through the posterior triangle.
You've got the external jugular and the vertebral veins running through the posterior triangle.
And then you've got this plexus of nerves, the brachial plexus, you've got the accessory
nerve, which innervates the trapezius.
Several structures run in the posterior triangle.
I've mentioned before a little bit about the fascial compartments of the neck.
The structures in the neck are organized into packages within layers of fascia.
Fascia is this tough fibrous connective tissue, which wraps around the different structures
and compartmentalizes it.
The different structures are contained in different layers of fascia.
You've got superficial fascia and then you've got the deep fascia.
So the superficial fascia contains the platysma muscle, which was that muscle I removed at
the start, which was that thin strap, sheet-like muscle.
And then you've got the deep fascia, which there are several different layers.
You've got the investing layer, you've got the carotid sheath, the pre-tracheal fascia
and the prevertebral fascia.
I'll just quickly show you a diagram to explain that.
I've got this diagram here.
Sorry about the resolution, but it does explain the fascial compartments.
We're looking at a cross-section of the neck.
This is anterior and this is posterior.
The superficial fascia isn't included on this diagram.
This is just the deep fascia of the neck.
So the superficial fascia would run outside of this and the platysma would be contained
here anteriorly in the superficial fascia.
So we've got the investing fascia, which encloses the entire neck.
You can see how it splits to surround the trapezius muscle posteriorly and anteriorly,
it splits to encapsulate the sternocleidomastoid muscle.
And then you've got these others fascial compartments.
So here, the fascia is all in green.
We're looking at the green areas.
This fascia here is the pre-tracheal fascia and it encloses the viscera of the neck.
It encloses the trachea, the thyroid gland.
It actually encloses the esophagus, which isn't shown on this diagram.
Just anterior to the pre-tracheal fascia, you can see these little oval shapes.
These represent the strap muscles, the infrahyoid muscles.
Then you've got this little circular fascia.
This is the carotid sheath.
This encloses the jugular vein, the carotid artery and the vagus nerve.
So this neurovascular bundle has its own sheath, the carotid sheath.
And then you've got the prevertebral fascia, which actually runs all the way back to enclose
the vertebral column and the muscles associated with it.
So you've got the prevertebral muscles, the anterior, middle and posterior scalene muscles
and the deep muscles of the back which are enclosed by the prevertebral fascia.
So just to quickly recap.
You've got superficial and deep fascia.
Superficial fascia runs outside the deep fascia and encloses the platysma muscle.
And then the deep fascia has four compartments.
You've got the investing layers, which surrounds the entire neck and encapsulates the trapezius
muscle and the sternocleidomastoid muscle.
You've got the carotid sheath, which contains the common carotid artery, the internal jugular
vein and the vagus nerve.
You've got the pre-tracheal fascia, which encloses the larynx, trachea, thyroid gland
and esophagus (the viscera of the neck).
And you've got the prevertebral fascia around the cervical vertebrae and the associated
deep muscles, scalene muscles and prevertebral muscles.
So that's the organization of the neck.