Cranial Nerves 2

Question 1

Accessory Nerve:

Answer 1

1) CN11
2) GSE Fibers
3) Spinal Roots
- LMN not formed by fibers from ventral or dorsal roots
- egress from accessory nucleus in lateral aspect of anterior gray column (C1-5)
- Run posterior to dentate ligament & anterior to dorsal roots
4) Cranial Roots
- consists of axons whose cell bodies reside in caudal part of the nucleus ambiguus
- run through jugular foramen w/fibers of CN10 (considered part of CN10)
5) UMN innervation
- ipsilateral mostly
- bilateral some
6) Dentate Ligament
- pia mater
- stabilize the spinal cord to CT (Pia mater)
7) 2 origins
- Accessory Spinal Nucleus (GSE)
- Caudal portion of Nucleus AMbiguus (SVE)

Question 2

Hypoglossal Nerve

Answer 2

1) CN12
2) GSE
3) Povides motor input to all intrinsic and extrinsic muscles of tongue
- Genioglossus
- styloglossus
- Hypoglossus
- EXCEPT PALATOGLOSSUS (CN10)
4) Arises from anterior surface of medulla
- pierce the dura at hypoglossal canal of occipital bone to leave the skull
5) Innervates muscles of neck area
- Thyro-hyoid
- Omo-hyoid
- Sterno-hyoid
- Sternoid-thyroid
- Omo-hyoid (posterior belly)