Anatomy of the facial nerve (CN VII) Flashcards
The role of facial nerve
Control facial expression
Salivating
Sensation for parts of skin
Perception of taste
4 types of function of CN VII
Somatic sensory
Special sensory
Branchial motor
Parasympathetic motor
Describe Parasympathetic motor function of CN VII
Lacrimal glands Nasal glands Palatal mucosal Submandibular glands Sublingual glands
Describe special sensory function of CN VII
Taste to anterior 2/3 of tongue
Describe somatic sensory function of CN VII
Small portion of skin at ear & external tympanic membrane
Describe branchial motor function of CN VII
Innervate
- Stylohyoid
- posterior belly of digastric
- Facial expression muscles
Course of facial nerve
Pontomedullary junction
- has a large motor root & small motor root ( nervus intermedius)
(Nervus intermedius carries taste, parasympathetic & somatic sensory fibers)
=> internal acoustic meatus (where nervous intermedius join with motor root)
=> facial canal (medial wall of tympanic cavity)
=> reach geniculate ganglion
(1)
=> becomes greater petrosal nerve
==> parasympathetic innervation to nasal glands, palatine glands, pharyngeal mucous glands, lacrimal glands
(2) Nerves to stapedius - motor innervation
(3) chorda tympani
-> exit stylomastoid foramen
-> anterior 2/3 of tongue
Posterior auricular nerve innervation
(1) Posterior auricular nerve - motor innervation of…..
- occipital belly of occipitofrontalis
- stylohyoid
- posterior belly of digastric muscle
Somatic sensory innervation pathway
Somatic sensory information
- > geniculate ganglion
- > info go to spinal trigeminal nucleus
5 branches of facial nerve
Temporal nerve Zygomatic nerve Buccal nerve Marginal mandibular nerve Cervical nerve
Name of the nucleus of facial nerve. Describe its function
Facial motor nucleus
(1) Dorsal
- Controls muscles of upper face
- Receives innervation from both right & left hemispheres of brain
(2) Ventral
- Controls muscles of lower face
- Receives innervation only from opposite hemisphere
Describe pathway of corneal reflex
Afferent sensory
- Nasociliary nerve
- > ophthalmic nerve V1
- > send info to spinal trigeminal nucleus
efferent sensory
- spinal trigeminal nucleus
- > send info to facial motor nucleus
- > innervate orbicularis oculi
Describe parasympathetic innervation to lacrimal gland of facial nerve
Preganglionic parasympathetic fibers -> superior salivatory nucleus -> nervus intermedius -> greater petrosal nerve -> pterygopalatine ganglion -> postganglionic fibers go to Zygomatic nerve V2 -> Lacrimal nerve -> lacrimal gland ===> tear production
Describe parasympathetic innervation to nasal gland & palatal mucosal salivary glands of facial nerve
Preganglionic parasympathetic fibers -> superior salivatory nucleus -> nervus intermedius -> greater petrosal nerve -> pterygopalatine ganglion => nasal nerves V2 to innervate nasal glands; palatine nerves V2 to innervate palatal mucosal salivary glands
Describe parasympathetic innervation to submandibular gland & sublingual glands of facial nerve
Preganglionic parasympathetic fibers
- > superior salivatory nucleus
- > nervus intermedius
- > chorda tympani
- > join lingual nerve
- > submandibular ganglion
Describe special sensory innervation to submandibular gland & sublingual glands of facial nerve
(1) Sensory info from anterior 2/3 of tongue
- > lingual nerve
- > chorda tympani
- > geniculate ganglion
- > nervus intermedius
- > nucleus of solitary tract
(2) Sensory from taste buds on palate
- > palatine nerves
- > greater petrosal nerve
- > nervus intermedius
- > nucleus of solitary tract
3 branches of extra cranial of CN VII
(1) Chorda tympani
(2) nerve to stapedius
(3) chorda tympani
