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

REVIEW - SENSORY INNERVATION OF THE HEAD - TOUCH, PAIN, TEMPERATURE TASTE

REVIEW CRANIAL NERVES - MANY CRANIAL NERVES ARE MOTOR

MOTORXII - Hypoglossal - muscles of tongueXI - Accessory - motor to sternocleidomastoid, trapeziusIV - Trochlear - eye muscle - Superior ObliqueVI - Abducens - eye muscle - Lateral Rectus

MOTOR AND AUTONOMICIII - Oculomotor - many eye muscles and Lev. Palp. Sup. + Parasympathetics (constrictor pupil, ciliary muscle)

OTHER CRANIAL NERVES PROVIDE SPECIAL SENSES

I - Olfactory nerve - smellII - Optic nerve - visionVIII - Vestibulo-cochlear nerve - hearing, balance

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 rootDorsal root

Ventral rootVentral root

SPINAL NERVE

Dorsal root ganglion Dorsal root ganglion

FOCUS ON GENERAL SENSATION (TOUCH, PAIN, TEMPERATURE) - ALSO TASTE

CONTAINED IN CRANIAL NERVES - V (Trigeminal), VII (Facial), IX (Glossopharyngeal), X (Vagus)

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

V1V2

V3

GENICULATEGANGLION - VII

TRIGEMINALSEMI-LUNARGANGLION

VII,VIII leaveInternalAuditoryMeatus

VII exit skull at StylomastoidForamen

CLINICAL - COMPRESSION ORDAMAGE TO SENSORY GANGLIA CAN PRODUCE PAIN OR SENSORY LOSS

CLINICAL TEST - PRECISE SENSATION (GSA) - TWO POINT DISCRIMINATION

V1 – OPHTHALMICDIVISION

V2 – MAXILLARYDIVISON

V3 – MANDIBULARDIVISION

TRIGEMINAL NERVE – PRECISE SENSATION (TOUCH, PAIN, ETC.) TO SKIN OF FACE, FOREHEAD

Boundary-Lateral edgeof eye

Boundary Lateral edgeof mouth

THREE DIVISIONS POSTERIORSIDE OF HEADAND ALL OF NECK -

CERVICAL SPINALNERVES - CERVICAL PLEXUS -C2 - C4

DORSAL PRIMARYRAMI ON POSTERIORSIDE

CLINICAL TEST OF V1:SUPRAORBITAL N.

EXCEPTION:SKIN OF OUTER EARALSO1) VII- FACIAL2) IX - GLOSSO-PHARYNGEAL3) X - VAGUS

CLINICAL - BELL'S PALSY (VII) - PARALYSIS OF FACIAL MUSCLES; IN RECOVERY, PATIENTS COMPLAIN OF EARACHES

V1 – OPHTHALMICDIVISION

V2 – MAXILLARYDIVISON

V3 – MANDIBULARDIVISION

EXCEPTION - SKIN OF OUTER EAR V, VII, IX, X

Boundary-Lateral edgeof eye

Boundary Lateral edgeof mouth

NOTE: SHORT CILIARY NERVES (III, CILIARY GANGLION) PARASYMPATHETIC ACTIVATED IN PUPILLARY LIGHT REFLEX NOT CORNEAL REFLEX

TRIGEMINAL NERVE ALSO INNERVATES CORNEA OF EYE

ORBICU-LARISOCULIM.

- 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 surfaceof eye; transparent; irregularitiesastigmatism

CORNEAHIGHLYSENSITIVETO TOUCH

CLINICAL TEST - CORNEAL REFLEX -TOUCH DETECTED BY V - PRODUCESBILATERAL CLOSING OF EYELIDS (VII)

CORNEAL REFLEX -V TO VII

NASALCAVITY

ORALCAVITY

NOTE:CRANIALDURAMATERIS ALSOINNERVATEDBY V(ex. NervusSpinosus V3)

TRIGEMINAL NERVE – ALSO INNERVATES STRUCTURES INSIDE OF HEAD

General Sensation -(GSA) touch, pain, etc. - V1 Anterior Ethmoidal N. - V2 Nasal Branches- V2 Nasopalatine N.

TRIGEMINAL (V1, V2) SENSORY TO NASAL CAVITYOLFACTORY N. PTERYGO-

PALATINE GANGLION

V1ANT. ETHMOIDALN.

V2 - NASOPALATINEN.

V2NASALBR.

Other nerves1.Olfactory N. - SMELL - in Olfactory Area2. 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

Air filled extensions ofNasal Cavity:- All Paired- Develop After birth - Lined by mucous membrane- Drain to NasalCavity

TRIGEMINAL INNERVATES PARANASAL AIR SINUSES

FRONTALSINUSES

ETHMOIDSINUSES

MAXILLARYSINUSES

PAIN FROM INFECTEDSINUSES IS ACUTE, LOCALIZED

SENSORY FROMBRANCHES OFV1, V2

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

FACIAL NERVE - VII - MOTOR AND SENSORY

MUSCLES OF FACIAL EXPRESSION

FACIALPARALYSIS -sagging face,loss of naso-labial fold,inability to close eyelid

STAPEDIUS - DAMAGE -HYPERCOUSIA - sounds seem too loud

MOSTLYREMEMBERMOTOR

BUCCINATOR MUSCLE - forms wall of mouth, damage - difficultychewing food,drips frommouth

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

GENICULATEGANGLION - VII

CHORDATYMPANI - arises in middle ear, joins Lingual nerve (from V3) Note: POST.

AURICULARNERVE -precise, touch toouter ear -Ear painin Bell'spalsy

DAMAGE - Loss oftaste to ant. 2/3 oftongue; decreasesalivation

CHORDA TYMPANI

LINGUAL NERVE (V3)

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

3. Carotid branchesSensory – Carotid sinus - blood PressureCarotid Body - CO2 in blood

4. Motor Nerve to Stylopharyngeus

5. Pharyngeal BranchesSensory to oropharynx

6. Tonsillar BranchesSensory to palatine tonsil

7. Lingual branchesSensory (touch) & taste to post. 1/3 of tongue

Tonsillar

Lingual

Pharyngeal br

Carotid

1. Tympanic br. toMIDDLE EAR

GLOSSOPHARYNGEAL NERVE (IX)

Motor Nerve to Stylopharyngeus

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 (PharyngealSensory branches) OUT - X - all muscles of Pharynx (except Stylopharyngeus), all muscles of palate (except Tensor Palati)

Carotid

Pharyngeal branches

GAG REFLEX

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 TONGUEVII - CHORDA TYMPANI

ANT. TO EPIGLOTTIS -X- VAGUS - IMPRECISE

POST. 1/3 OF TONGUEIX - GLOSSO-PHARYNGEAL - IMPRECISE

ANT. 2/3 OF TONGUEV3 - LINGUAL N.PRECISE TOUCH

PRECISESENSATION

IMPRECISE

TOUCH - PRECISE TO ANT. 2/3IMPRECISE TO POST. 1/3