parotid gland and facial nerve

Question 1

facial nerve nuclei

Answer 1

motor nucleus, solitary nucleus, superior salivatory nucleus

Question 2

motor nucleus supply

Answer 2

muscles of facial expression

Question 3

solitary nucleus supply

Answer 3

taste and visceral sensation

Question 4

superior salivatory nucleus supply

Answer 4

parasympathetic secretomotor to lacrimal gland, nasal and oral cavities, submandibular and sublingual salivary glands

Question 5

where does the facial nerve enter and who does it travel with?

Answer 5

CN VII with the intermediate nerve enters at the internal acoustic meatus with the vestibulocochlear nerve and the labyrinthine artery

Question 6

what would damage to the facial nerve at the site of the internal acoustic meatus cause?

Answer 6

-affect to the muscles of facial expression
-affect the stapedius (muscle in the ear) causing hyperacusis (which is the inability to tolerate high pitches sounds)

Question 7

CN VII course through middle ear

Answer 7

-CN VII and intermediate nerve enters the internal acoustic meatus along with the vestibulocochlear nerve and labyrinthine artery
- the first branch given off is the greater petrosal nerve
- it travels through its bony canal and gives off the nerve to stapedius (muscle in middle ear)
- then exits through the stylomastoid foramen (which between the styloid process and mastoid process)

Question 8

CN VII course (post middle ear)

Answer 8

-CN VII emerges from the stylomastoid foramen where 2 branches are given off-posterior auricular & digastric nerve
-before the main nerve enters the parotid gland where 5 terminal branches arise from a plexus within this gland

Question 9

5 branches of the facial nerve (5 fingaz to the face)

Answer 9

temporal, zygomatic, buccal, marginal mandibular and cervical

Question 10

what is not formed at birth and what is the risk of this

Answer 10

At birth the mastoid process has not formed & CN VII is at risk of compression/injury during forceps delivery leading to paralysis of the facial muscles

Question 11

effect of a central lesion in brain (higher in brain)

Answer 11

would mean the upper half of the face would still be innervated (patient could still wrinkle forehead)
(stroke)

Question 12

effect of peripheral lesion (lower down in brain)

Answer 12

will mean whole of one side of the face is not innervated (patient could not move forehead) – bells palsy
(All fibers of facial nerve effected)

Question 13

which structures are embedded within the parotid gland

Answer 13

• retromandibular vein
  -external carotid artery
  -CN VII
  -parotid lymph nodes

Question 14

parasympathetic innervation (secretomotor innervation to produce saliva) of parotid gland

Answer 14

-Preganglionic fibres from glossopharyngeal nerve (CN IX) travel to the otic ganglion in the tympanic nerve & lesser petrosal nerve
- Postganglionic fibres from the otic ganglion pass to the auriculotemporal nerve (CN V3) that sends branches to the parotid gland

Question 15

sympathetic innervation of parotid gland

Answer 15

-Sympathetic innervation is derived from the superior cervical ganglion & the nerve plexus on the external carotid artery

-This results mainly in vasoconstriction & some reduction in the volume of saliva that leads to dry mouth

(fight or flight reaction)