Hypoglossal Nerve

Question 1

Hypoglossal nerve

Answer 1

12th cranial nerve

Question 2

Origin

Answer 2

It is a motor nerve from hypoglossal nucleus in medulla

Question 3

Course

Answer 3

1. Leaves skull through hypoglossal canal
2. Descend inside carotid sheath between ICA and IJV deep to posterior digastric
3. Curves forwards
4. Cross ICA, ECA, and lingual artery loop
5. Enter digastric triangle
6. Pass on Hyoglossus below submandibular gland deep part and it’s duct
7. End in genioglossus by dividing into many branches
8. Just below the skull: joined by branch from C1 to be distributed with its branches

Question 4

Branches

Answer 4

1. All extrinsic muscles tongue
2. All intrinsic muscles tongue
3. Branches from C1

Question 5

All extrinsic muscles tongue

Answer 5

Except Palatoglossus (styloglossus, Hyoglossus, and genioglossus)

Question 6

Branches from C1

Answer 6

1. Meningeal branch
2. Descendens hypoglossi (ansa cervicalis)
3. Thyrohyoid branch
4. Geniohyoid branch

Question 7

Applied anatomy

Answer 7

Injury leads to:
1. Tongue hemiatrophy on affected side
2. On tongue protrusion it deviates to affected side