Hyoid Apparatus Flashcards
What anterior rami contribute to the cervical plexus?
The anterior rami of C1-C4.
What is the structure of the cervical plexus?
It forms nerve loops (like the ansa cervicalis) and branches which come off of those loops.
Where is the cervical plexus found?
Anteromedial to the levator scapula and the middle scalene, deep to the sternocleidomastoid.
Where do the cutaneous branches pass?
They pass posteriorly before looping and going to the skin. They are superficial.
Where do the motor branches pass?
They pass anteromedially, and are deep.
What are two motor branches of the cervical plexus?
The phrenic nerve and the ansa cervicalis.
What does the ansa cervicalis supply?
It supplies the omohyoid, the sternohyoid, and the sternothyroid.
What are the two loops of the ansa cervicalis?
The superior loop and the inferior loop.
What makes up the superior loop of the ansa cervicalis?
C1-C2. It hitchhikes on CN XII (hypoglossal nerve) for a while.
What makes up the inferior root of the ansa cervicalis?
C2-C3.
What innervates the thyrohyoid?
C1 fibers that travel with CN XII independent of the superior root. It is the only infrahyoid muscle not innervated by the ansa cervicalis.
Where do the cutaneous branches of the cervical plexus arise?
At the nerve point of the neck.
Where is the nerve point of the neck located?
On the middle/posterior border of the SCM.
What do the cutaneous branches supply?
They supply the skin of the neck, the superolateral thoracic wall, the scalp between the ear, and the external occipital protuberance.
What are the cutaneous nerves of the cervical plexus?
- Lesser occipital nerve (C2)
- Great auricular nerve (C2-C3)
- Transverse cervical nerve (C2-C3)
- Supraclavicular nerve (C3-C4)
