CRANIAL NERVES II. HITCHHIKING PATHWAYS AND BRANCHES OF VII, IX

                                                                                                                                                                                © 2005 zillmusom

I. REVIEW OF FUNCTIONAL COMPONENTS

 

                        SVE                GVE                GSA                GVA                SVA

 

V                     +                                             +

 

VII, IX              +                     +                     +                     +                     +

 

Note: V is sensory to face and oral and nasal cavity, motor to muscles derived from first branchial arch; leaves brainstem with no parasympathetics autonomics (GVE) or taste fibers (SVA); VII, IX have taste fibers and parasympathetics.

 

II. PARASYMPATHETICS AND TASTE FIBERS OF VII AND IX JOIN BRANCHES OF V

 

            A. Parasympathetics

NERVE

PRE-GANGLIONIC

FIBER IN

POST-GANGLIONIC FIBERS ARISE IN

JOINS

INNERVATES

VII

Greater Petrosal n.

Pterygopalatine ganglion

Zygomatic nerve (V2) to Lacrimal n. (V1) to

Lacrimal gland

VII

Greater Petrosal n.

Pterygopalatine ganglion

 

1) Nasopalatine n. (V2)

2) Nasal branches (V2)

3) Greater and Lesser

Palatine nn. (V2)

Mucous glands of nose and palate

VII

Chorda Tympani

Submandibular

Ganglion

Lingual n. (V3)

Submandibular,

sublingual salivary glands

IX

Lesser Petrosal n.

Otic ganglion

Auriculotemporal n. (V3)

Parotid gland

 

            B. Taste fibers

NERVE

LEAVE BY

JOIN

INNERVATES TASTE BUDS OF

VII

Chorda Tympani

Lingual n. (V3)

Anterior 2/3 of tongue

IX

Lingual branches

direct to

Posterior 1/3 of tongue

X

Superior Laryngeal n.

direct to

Anterior to epiglottis

 

III. FACIAL NERVE  ‑ (Atlas Figs. Pages 812, 813)

 

branches in facial canal

 

                        1. Greater Petrosal Nerve

 

                                    a. Forms nerve of pterygoid canal, ends in Pterygopalatine (sphenopalatine) ganglion

 

                                    b. contains ‑ parasympathetics to lacrimal gland, mucous glands of nose and palate; sensory fibers to nasopharynx.

 

                        2. Stapedial Nerve ‑ motor to stapedius muscle

 

                        3. Chorda tympani

 

                                    a. passes through tympanic cavity, exits via petrotympanic fissure, joins Lingual Nerve (V3)

            

                                    b. contains ‑ taste fibers to anterior tongue (SVA); parasympathetics to submandibular, sublingual glands (GVE).

 

                        4. Posterior Auricular Nerve ‑ joins branches of X; sensory to outer ear, motor to auricular muscles, occipitalis

 

Facial nerve leaves facial canal via stylomastoid foramen, remaining branches motor

 

                        5. Motor branches to stylohyoid and posterior belly of digastric

 

                        6. Branches to muscles of facial expression

 

                                    a. temporal

                                    b. zygomatic

                                    c. buccal - courses lateral to Masseter muscle

                                    d. mandibular

                                    e. cervical

 

IV. GLOSSOPHARYNGEAL NERVE (Atlas Figs. pages 816, 817)

 

                        1. Tympanic Nerve ‑ forms tympanic plexus, sensory to middle ear, mastoid air sinus, auditory tube

 

                        2. Lesser Petrosal Nerve ‑ (often a branch of tympanic plexus)

 

                                    a. passes through middle ear into cranium, out again via foramen ovale, joins V3

 

                                    b. contains ‑ parasympathetics to parotid gland (synapse in otic ganglion)

 

                        3. Carotid branches ‑ to carotid sinus ‑ baroreception (pressure); to carotid body ‑ chemoreception

 

                        4. Nerve to stylopharyngeus muscle ‑ only voluntary motor nerve in IX

 

                        5. Pharyngeal branches ‑ sensory to mucosa of pharynx

 

                        6. Tonsillar branches ‑ to palatine tonsil

 

                        7. Lingual branches ‑ contain taste fibers of posterior 1/3 of tongue

                                                            - contain touch fibers of posterior 1/3 of tongue