1. FOCUSED REVIEW - SENSORY INNERVATION OF THE HEAD - TOUCH, PAIN, TEMPERATURE AND TASTE Mini review of topics not clearly remembered Goal - under 30 minutes 'No sinner was ever saved after the first 20 minutes of a sermon' - Mark Twain

2. REVIEW - SENSORY INNERVATION OF THE HEAD - TOUCH, PAIN, TEMPERATURE TASTE REVIEW CRANIAL NERVES - MANY CRANIAL NERVES ARE MOTOR MOTOR XII - Hypoglossal - muscles of tongue XI - Accessory - motor to sternocleidomastoid, trapezius IV - Trochlear - eye muscle - Superior Oblique VI - Abducens - eye muscle - Lateral Rectus MOTOR AND AUTONOMIC III - Oculomotor - many eye muscles and Lev. Palp. Sup. + Parasympathetics (constrictor pupil, ciliary muscle) OTHER CRANIAL NERVES PROVIDE SPECIAL SENSES I - Olfactory nerve - smell II - Optic nerve - vision VIII - Vestibulo-cochlear nerve - hearing, balance

3. REVIEW - SENSORY NEURONS IN SPINAL NERVES Components and Structures 1. Dorsal root of spinal nerve - contains afferent (sensory) axons. 2. Dorsal root ganglion - cell bodies of all sensory neurons (somatic and visceral) are located at dorsal root ganglia; look like swellings attached to dorsal root. 3. Ventral root of spinal nerve - contains efferent (motor) axons Dorsal root Ventral root SPINAL NERVE Dorsal root ganglion FOCUS ON GENERAL SENSATION (TOUCH, PAIN, TEMPERATURE) - ALSO TASTE CONTAINED IN CRANIAL NERVES - V (Trigeminal), VII (Facial), IX (Glossopharyngeal), X (Vagus)

4. SENSORY GANGLIA ARE ATTACHED TO CRANIAL NERVES Cell bodies of sensory neurons in Trigeminal Nerve are in Trigeminal (Semilunar) Ganglion Cell bodies of sensory neurons in VII (Facial Nerve) in Geniculate Ganglion V1 V2 V3 GENICULATE GANGLION - VII TRIGEMINAL SEMI- LUNAR GANGLION VII, VIII leave Internal Auditory Meatus VII exit skull at Stylomastoid Foramen CLINICAL - COMPRESSION OR DAMAGE TO SENSORY GANGLIA CAN PRODUCE PAIN OR SENSORY LOSS

5. CLINICAL TEST - PRECISE SENSATION (GSA) - TWO POINT DISCRIMINATION V1 – OPHTHALMIC DIVISION V2 – MAXILLARY DIVISON V3 – MANDIBULAR DIVISION TRIGEMINAL NERVE – PRECISE SENSATION (TOUCH, PAIN, ETC.) TO SKIN OF FACE, FOREHEAD Boundary- Lateral edge of eye Boundary Lateral edge of mouth THREE DIVISIONS POSTERIOR SIDE OF HEAD AND ALL OF NECK - CERVICAL SPINAL NERVES - CERVICAL PLEXUS - C2 - C4 DORSAL PRIMARY RAMI ON POSTERIOR SIDE CLINICAL TEST OF V1: SUPRAORBITAL N.

6. EXCEPTION: SKIN OF OUTER EAR ALSO 1) VII- FACIAL 2) IX - GLOSSO- PHARYNGEAL 3) X - VAGUS CLINICAL - BELL'S PALSY (VII) - PARALYSIS OF FACIAL MUSCLES; IN RECOVERY, PATIENTS COMPLAIN OF EARACHES V1 – OPHTHALMIC DIVISION V2 – MAXILLARY DIVISON V3 – MANDIBULAR DIVISION EXCEPTION - SKIN OF OUTER EAR V, VII, IX, X Boundary- Lateral edge of eye Boundary Lateral edge of mouth

7. NOTE: SHORT CILIARY NERVES (III, CILIARY GANGLION) PARASYMPATHETIC ACTIVATED IN PUPILLARY LIGHT REFLEX NOT CORNEAL REFLEX TRIGEMINAL NERVE ALSO INNERVATES CORNEA OF EYE ORBICU- LARIS OCULI M. - Palpebral part - Close eyelids - Orbital part - Buries eyelids, Ex. sandstorm LONG CILIARY NERVES (V1) - SENSORY TO CORNEA V- TOUCH CORNEA VII - CLOSE EYELID CORNEA - on surface of eye; transparent; irregularities astigmatism CORNEA HIGHLY SENSITIVE TO TOUCH CLINICAL TEST - CORNEAL REFLEX - TOUCH DETECTED BY V - PRODUCES BILATERAL CLOSING OF EYELIDS (VII) CORNEAL REFLEX - V TO VII

8. NASAL CAVITY ORAL CAVITY NOTE: CRANIAL DURA MATER IS ALSO INNERVATED BY V (ex. Nervus Spinosus V3) TRIGEMINAL NERVE – ALSO INNERVATES STRUCTURES INSIDE OF HEAD

9. General Sensation - (GSA) touch, pain, etc. - V1 Anterior Ethmoidal N. - V2 Nasal Branches - V2 Nasopalatine N. TRIGEMINAL (V1, V2) SENSORY TO NASAL CAVITY OLFACTORY N. PTERYGO- PALATINE GANGLION V1 ANT. ETHMOIDAL N. V2 - NASOPALATINE N. V2 NASAL BR. Other nerves 1.Olfactory N. - SMELL - in Olfactory Area 2. branches of Facial N. (VII) - PARASYMPATHETICS to Mucous Glands of nose - GVE - from Pterygopalatine Ganglion (hitchhike with branches of V2 (Nasal, Nasopalatine N.) CLINICAL - NASAL CAVITY HAS PRECISE SENSATION; PAIN IS INTENSE AND LOCALIZED

10. Air filled extensions of Nasal Cavity: - All Paired - Develop After birth - Lined by mucous membrane - Drain to Nasal Cavity TRIGEMINAL INNERVATES PARANASAL AIR SINUSES FRONTAL SINUSES ETHMOID SINUSES MAXILLARY SINUSES PAIN FROM INFECTED SINUSES IS ACUTE, LOCALIZED SENSORY FROM BRANCHES OF V1, V2

11. A. Frontal - separate by septum, variable size C. Ethmoid- also called air cells (Ant., Mid., Post.) B. Sphenoid - in body of Sphenoid bone All usually paired PARANASAL AIR SINUSES VIEW: FLOOR OF ANT. CRAN. FOSSA WITH BONE REMOVED NOSE Ethmoid - Blocked Sinus Infection Can Spread to Orbit

12. FACIAL NERVE - VII - MOTOR AND SENSORY MUSCLES OF FACIAL EXPRESSION FACIAL PARALYSIS - sagging face, loss of naso- labial fold, inability to close eyelid STAPEDIUS - DAMAGE - HYPERCOUSIA - sounds seem too loud MOSTLY REMEMBER MOTOR BUCCINATOR MUSCLE - forms wall of mouth, damage - difficulty chewing food, drips from mouth

13. FACIAL NERVE (VII) - SENSORY INNERVATION TO HEAD SENSORY FIBERS IN FACIAL NERVE - Chorda Tympani - - taste to ant 2/3 of tongue - parasymp.to Submandibular, Sublingual salivary glands - Gleek GENICULATE GANGLION - VII CHORDA TYMPANI - arises in middle ear, joins Lingual nerve (from V3) Note: POST. AURICULAR NERVE - precise, touch to outer ear - Ear pain in Bell's palsy DAMAGE - Loss of taste to ant. 2/3 of tongue; decrease salivation CHORDA TYMPANI LINGUAL NERVE (V3)

14. HEAD ALSO HAS VISCERAL SENSORY INNERVATION Nasal Cavity Oral Cavity IMPRECISE SENSATION - PHARYNX AND DERIVATIVES - VISCERAL SENSORY GVA - IN 3 CRANIAL NERVES NASOPHARYNX - VII OROPHARYNX - IX LARYNGOPHARYNX - X Note: Authors disagree on innervation of nasopharynx PRECISE SENSATION - SOMATIC GSA - MOSTLY IN V

15. 3. Carotid branches Sensory – Carotid sinus - blood Pressure Carotid Body - CO2 in blood 4. Motor Nerve to Stylopharyngeus 5. Pharyngeal Branches Sensory to oropharynx 6. Tonsillar Branches Sensory to palatine tonsil 7. Lingual branches Sensory (touch) & taste to post. 1/3 of tongue Tonsillar Lingual Pharyngeal br Carotid 1. Tympanic br. to MIDDLE EAR GLOSSOPHARYNGEAL NERVE (IX) Motor Nerve to Stylopharyngeus

16. DAMAGE TO GLOSSOPHARYNEAL NERVE IX –CENTRAL LESIONS – Nucleus solitarius - GVA-- 9,10: cardiac-pulmonary areflexia; loss of chemo- baro-sensory afferents in the carotid sinus/body (Carotid branch IX) IX – GAG REFLEX IN - IX (Pharyngeal Sensory branches) OUT - X - all muscles of Pharynx (except Stylopharyngeus), all muscles of palate (except Tensor Palati) Carotid Pharyngeal branches GAG REFLEX

17. SENSORY INNERVATION OF TONGUE MOTOR - ALL MUSCLES INNERVATED BY XII HYPOGLOSSAL – TONGUE DEVIATES TOWARD SIDE OF HYPOGLOSSAL LESION (GENIOGLOSSUS) TASTE ANT. TO EPIGLOTTIS - X- VAGUS POST. 1/3 OF TONGUE - IX - GLOSSO- PHARYNGEAL ANT. 2/3 OF TONGUE VII - CHORDA TYMPANI ANT. TO EPIGLOTTIS - X- VAGUS - IMPRECISE POST. 1/3 OF TONGUE IX - GLOSSO- PHARYNGEAL - IMPRECISE ANT. 2/3 OF TONGUE V3 - LINGUAL N. PRECISE TOUCH PRECISE SENSATION IMPRECISE TOUCH - PRECISE TO ANT. 2/3 IMPRECISE TO POST. 1/3