Cranial Nerve 7

Question 1

Facial nerve

Answer 1

Emerges from brainstem at ventrolateral aspect of caudal pons, near pontomedullary junction

-Large SVE (motor root) and smaller root called nervus intermedius *GVE, SA, GSA, GVA

Question 2

Intraosseuous course of facial nerve

Answer 2

Traverses internal acoustic meatus and enters facial canal

• travels laterally within facial canal
• medial to tympanic cavity, enlargement - geniculate ganglion
• just beyond ganglion, sharp posterior bend in Cn-7 and then nerve courses inferolateral within facial canal to reach stylomastoid foramen.

Question 3

Branches of facial n as it traverses facial canal

Answer 3

1. Greater petrosal nerve
2. Chorda tympani nerve
3. N to stapedius
4. Sensory branch(GSA) of CN-7 (joins CN10)
   (GCSS)

Question 4

Branches of facial nerve after exiting skull via stylomastoid foramen

Answer 4

5. Posterior auricular nerve
6. Digastric branch
7. Stylohyoid branch
8. Temporal branch
9. Zygomatic branch
10. Buccal branch
11. Mandibular/marginal mandibular branch
12. Cervical branch

Question 5

Greater petrosal nerve

Answer 5

Emerges from geniculate ganglion and travels within temporal bone before passing into middle cranial fossa via hiatus for greater petrosal nerve.
- Passes toward internal opening of carotid canal, unites with deep petrosal nerve (sympathetic fibers)–> nerve of pterygoid canal. (travel along/within cartilage that fills foramen lacerum –> traverse pterygoid canal –> enter PPG

Question 6

Chorda tympani

Answer 6

Emerges within facial canal; travels superior and anterior before passing toward tympanic cavity via posterior canaliculus for chorda tympani.

• Proceeds anteriorly, travels within layers of tympanic membrane and across handle of malleus. Re-enters temporal bone via anterior canaliculus for chorda tympani
• Leaves temporal bone via petrotympanic fissure and enters infra temporal fossa