Parotid gland and Facial Nerve Flashcards
What nerve innervates the parotid?
CNIX - glossopharyngeal
What type of secretions does parotid have?
Serous
What is the venous drainage of the parotid?
The retromandibular vein
Joined from superficial temporal and maxillary vein (match with arteries)
Eventually drains into IJV
What is the arterial supply of the parotid?
The ECA
The terminal branches - superficial temporal and maxillary arteries
What nerve innervates the parotid sheath and overlying skin of parotid?
Auriculotemporal nerve (branch of CNV3)
What is the parasympathetic innervation to the parotid? (preganglionic and postganglionic fibres)
Preganglionic fibres from CNIX travel to otic ganglion in tympanic and lesser petrosal nerve.
Postganglionic fibres from otic ganglion pass to auriculotemporal nerve that sends branches to parotid.
What is the sympathetic innervation of the parotid?
External carotid plexus
Where does the facial nerve exit the skull?
Stylomastoid foramen
What does the temporal branch of the facial nerve supply?
Muscles of the temple, forehead and supra-orbital area.
What does the zygomatic branch of CNVII supply?
Muscles of infra-orbital area, the lateral nasal area and the upper lip.
Orbicularis oris
What does the buccal branch of CNVII supply?
Muscles of the cheek, upper lip and corner of mouth
What does the mandibular branch of CNVII supply?
Muscles of the lower lip and chin
Cervical branch of CNVII supply?
Platysma
Describe the symptoms of Bell’s Palsy
Unilateral paralysis of the facial muscles
Cannot close the eye fully (or at all) - need to protect the eye to prevent eye damage or vision impairment.
Drooping of side of face
Where does the parotid duct travel?
Travels across the parotid gland the pierces the buccinator. Opening of the duct is at the upper 2nd molar.
Where is the parotid region?
Covers the area anterior to ears and inferior to zygomatic arch
Where is the parotid gland located?
In the “parotid bed” - antero-inferior to external acoustic meatus.
What is another name for parotid duct?
Stensens duct
Describe the infratemporal portion of CNVII
Exits pons as 2 roots - motor and (sensory and parasympathetic)
Enter internal acoustic meatus and then facial canal
2 roots fuse and become geniculate ganglion
Greater petrosal nerve branches at this point
Nerve to stapedius
Chorda tympani
Exits through stylomastoid foramen
Describe extratemporal portion of CNVII
Exits skull at stylomastoid foramen
Gives posterior auricular and digastric branch.
Enters the parotid
What is a common complication of parotid surgery or parotidectomy (removal of parotid gland)?
Facial paralysis
Facial nerve injury or bruising
What can happen as a result of damage to the zygomatic branch of CNVII?
Paralysis of orbicularis oculi.
Causes inferior eyelid to fall away from eye.
Lacrimal fluid is the not spread across cornea and eye can be scarred or vulnerable to ulceration.
What are some symptpoms of Bell’s palsy?
Unilateral paralysis of upper and lower parts of the face
How can Bell’s palsy be treated?
Steroids (do not always help)
Sometimes anti-viral prescribed
EYE TREATMENT - eyedrops and patch
Surgical
What nerve can be used for a graft for the facial nerve if damage is likely to occur?
Greater auricular
