Parotid Region Flashcards
parotid region is
anterior to the ear and inferior to the zygomatic arch
parotid gland
largest of the 3 salivary glands with an almost entirely serous secretion
parotid gland is enclosed in
parotid sheath which is derived from investing layer of deep cervical fascia
course of parotid duct
passes horizontally from anterior edge of gland superficially to the masseter before piercing the buccinator and entering oral cavity near upper 2nd molar tooth
name 4 structures embedded in the parotid
- retromandibular vein (from superficial temporal & maxillary) - venous drainage
- ECA (posterior auricular, maxillary, superficial temporal) - arterial supply
- parotid lymph nodes
- CN VII - this does not innervate parotid gland !
arterial supply of parotid gland
from branches of ECA that run through it i.e. posterior auricular, maxillary and superficial temporal
venous drainage of parotid gland
veins that run alongside arteries i.e. maxillary vein, superficial temporal vein which join to form retromandibular vein
parasympathetic innervation of parotid gland
preganglionic - fibres from CN IX travel to otic ganglion in tympanic nerve and lesser petrosal nerve
postganglionic - fibres from otic ganglion pass to auriculotemporal nerve (CN V3) that sends branches to parotid
parasympathetic innervation is responsible for
production of saliva
sympathetic innervation of parotid is from
superior cervical ganglion & nerve plexus on ECA
infratemporal portion of CN VII
the first part of the nerve from where it exits the pons to where it exits the skull
infratemporal portion of CN VII exits as
2 roots:
1. motor root
2. nervus intermedius (sensory root)
the 2 roots of the infratemporal portion of CN VII enter
the internal acoustic meatus and then the facial canal
when the 2 roots of the infratemporal portion of CN VII join they form
the geniculate ganglion
what branch comes off the geniculate ganglion
greater petrosal nerve to supply parasympathetic innervation to the nasal and lacrimal glands
before exiting the skull the facial nerve gives off 2 branches
- nerve to stapedius which supplies motor innervation to the stapedius muscle
- chorda tympani which hitchhikes alongside the lingual nerve to supply taste and sensation to the anterior 2/3 of the tongue
how does facial nerve exit the skull
stylomastoid foramen
extratemporal part of CN VII
2nd part of the nerve from where it exits the skull at the stylomastoid foramen
how does CN VII divide in the extratemporal portion
2 branches given off at the beginning; posterior auricular and digastric. it then enters the parotid to split into 5 main branches
what does the facial nerve form in the parotid gland
the parotid plexus
what are the 5 terminal branches of the facial nerve
- temporal
- zygomatic
- buccal
- marginal mandibular
- cervical
what does the temporal branch innervate
muscles of the temple, forehead, supra-orbital area
what does the zygomatic branch innervate
muscles of the infra-orbital area, lateral nasal area and upper lip
what does the buccal branch innervate
muscles of the cheek, upper lip, corner of the mouth
what does the marginal mandibular branch innervate
muscles of the lower lip and chin
what does the cervical branch innervate
platysma
what is Bell’s palsy and where does it affect
most common type of facial paralysis. in most cases it affects both upper and lower parts of the face and is unilateral
