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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
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
FOCUS ON GENERAL SENSATION (TOUCH, PAIN,
TEMPERATURE) - ALSO TASTE
CONTAINED IN CRANIAL NERVES - V (Trigeminal),
VII (Facial), IX (Glossopharyngeal), X (Vagus)
REVIEW - SENSORY NEURONS
IN SPINAL NERVES
Dorsal root ganglion
Dorsal root
Ventral root
Dorsal root ganglion
Dorsal root
Ventral root
SPINAL
NERVE
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
SENSORY GANGLIA ARE ATTACHED TO CRANIAL NERVES
Cell bodies of sensory neurons in Trigeminal
Nerve are in Trigeminal (Semilunar) Ganglion
TRIGEMINAL
SEMILUNAR
GANGLION
VII,
VIII leave
Internal
Auditory
Meatus
V2
Cell bodies of sensory neurons in
VII (Facial Nerve) in Geniculate
Ganglion
GENICULATE
GANGLION - VII
V1
V3
VII exit skull at Stylomastoid
Foramen
CLINICAL - COMPRESSION OR
DAMAGE TO SENSORY GANGLIA CAN
PRODUCE PAIN OR SENSORY LOSS
TRIGEMINAL NERVE – PRECISE SENSATION (TOUCH,
PAIN, ETC.) TO SKIN OF FACE, FOREHEAD
THREE DIVISIONS
V1 – OPHTHALMIC
DIVISION
BoundaryLateral edge
of eye
V2 – MAXILLARY
DIVISON
Boundary
Lateral edge
of mouth
POSTERIOR
SIDE OF HEAD
AND ALL OF NECK CERVICAL SPINAL
NERVES CERVICAL PLEXUS C2 - C4
DORSAL PRIMARY
RAMI ON POSTERIOR
SIDE
V3 – MANDIBULAR
DIVISION
CLINICAL TEST - PRECISE SENSATION (GSA)
- TWO POINT DISCRIMINATION
CLINICAL TEST OF V1:
SUPRAORBITAL N.
EXCEPTION - SKIN OF OUTER EAR V, VII, IX, X
V1 – OPHTHALMIC
DIVISION
BoundaryLateral edge
of eye
V2 – MAXILLARY
DIVISON
Boundary
Lateral edge
of mouth
V3 – MANDIBULAR
DIVISION
EXCEPTION:
SKIN OF
OUTER EAR
ALSO
1) VII- FACIAL
2) IX GLOSSOPHARYNGEAL
3) X - VAGUS
CLINICAL - BELL'S PALSY (VII) - PARALYSIS OF FACIAL
MUSCLES; IN RECOVERY, PATIENTS COMPLAIN OF EARACHES
TRIGEMINAL NERVE ALSO INNERVATES CORNEA OF EYE
CORNEAL REFLEX V TO VII
CORNEA - on surface
of eye; transparent;
irregularities
astigmatism
CORNEA
HIGHLY
SENSITIVE
TO TOUCH
VII - CLOSE EYELID
V- TOUCH CORNEA
LONG CILIARY NERVES (V1)
- SENSORY TO CORNEA
NOTE: SHORT CILIARY
NERVES (III, CILIARY
GANGLION)
PARASYMPATHETIC
ACTIVATED IN PUPILLARY
LIGHT REFLEX NOT
CORNEAL REFLEX
ORBICULARIS
OCULI
M.
- Palpebral part - Close eyelids
- Orbital part - Buries eyelids, Ex.
sandstorm
CLINICAL TEST - CORNEAL REFLEX TOUCH DETECTED BY V - PRODUCES
BILATERAL CLOSING OF EYELIDS (VII)
TRIGEMINAL NERVE – ALSO INNERVATES STRUCTURES
INSIDE OF HEAD
NASAL
CAVITY
ORAL
CAVITY
NOTE:
CRANIAL
DURA
MATER
IS ALSO
INNERVATED
BY V
(ex. Nervus
Spinosus V3)
TRIGEMINAL (V1, V2) SENSORY TO NASAL CAVITY
OLFACTORY N.
General Sensation (GSA) touch, pain, etc.
- V1 Anterior Ethmoidal
N.
- V2 Nasal Branches
- V2 Nasopalatine N.
V2
V1
PTERYGOPALATINE
GANGLION
NASAL
BR.
ANT.
ETHMOIDAL
N.
CLINICAL - NASAL CAVITY
HAS PRECISE SENSATION;
PAIN IS INTENSE AND
LOCALIZED
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.)
V2 - NASOPALATINE
N.
TRIGEMINAL INNERVATES PARANASAL AIR SINUSES
SENSORY FROM
BRANCHES OF
V1, V2
FRONTAL
SINUSES
ETHMOID
SINUSES
MAXILLARY
SINUSES
Air filled extensions of
Nasal Cavity:
- All Paired
- Develop After birth
- Lined by mucous
membrane
- Drain to Nasal
Cavity
PAIN FROM INFECTED
SINUSES IS ACUTE, LOCALIZED
PARANASAL AIR SINUSES
All usually paired
VIEW: FLOOR OF
ANT. CRAN. FOSSA
WITH BONE
REMOVED
NOSE
A. Frontal separate by
septum, variable
size
C. Ethmoid- also
called air cells
(Ant., Mid.,
Post.)
B. Sphenoid - in
body of
Sphenoid bone
Ethmoid - Blocked Sinus Infection Can Spread to Orbit
FACIAL NERVE - VII MOTOR AND SENSORY
STAPEDIUS - DAMAGE HYPERCOUSIA - sounds
seem too loud
MOSTLY
REMEMBER
MOTOR
MUSCLES OF
FACIAL
EXPRESSION
FACIAL
PARALYSIS sagging face,
loss of nasolabial fold,
inability to close
eyelid
BUCCINATOR
MUSCLE - forms
wall of mouth,
damage difficulty
chewing food,
drips from
mouth
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
CHORDA TYMPANI
GENICULATE
GANGLION - VII
CHORDA
TYMPANI arises in middle
ear, joins Lingual
nerve (from V3)
DAMAGE - Loss of
taste to ant. 2/3 of
tongue; decrease
salivation
LINGUAL NERVE (V3)
Note: POST.
AURICULAR
NERVE precise, touch
to
outer ear Ear pain
in Bell's
palsy
HEAD ALSO HAS VISCERAL SENSORY INNERVATION
PRECISE SENSATION SOMATIC GSA MOSTLY IN V
Nasal
Cavity
IMPRECISE SENSATION PHARYNX AND DERIVATIVES
VISCERAL SENSORY GVA IN 3 CRANIAL NERVES
NASOPHARYNX - VII
Oral
Cavity
OROPHARYNX - IX
LARYNGOPHARYNX - X
Note: Authors disagree on
innervation of nasopharynx
GLOSSOPHARYNGEAL NERVE (IX)
1. Tympanic br. to
MIDDLE EAR
Motor Nerve to
Stylopharyngeus
Tonsillar
Lingual
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
Carotid
7. Lingual branches
Sensory (touch) & taste to
post. 1/3 of tongue
Pharyngeal
br
DAMAGE TO GLOSSOPHARYNEAL NERVE
GAG REFLEX
Carotid
Pharyngeal
branches
IX – GAG REFLEX
IN - IX (Pharyngeal
Sensory branches)
OUT - X - all muscles of
Pharynx (except
Stylopharyngeus), all
muscles of palate (except
Tensor Palati)
IX –CENTRAL LESIONS –
Nucleus solitarius - GVA-9,10: cardiac-pulmonary
areflexia; loss of chemobaro-sensory afferents in
the carotid sinus/body
(Carotid branch IX)
SENSORY INNERVATION OF TONGUE
TOUCH - PRECISE TO ANT. 2/3
TASTE
IMPRECISE TO POST. 1/3
ANT. TO EPIGLOTTIS X- VAGUS - IMPRECISE
POST. 1/3 OF TONGUE
IX - GLOSSOPHARYNGEAL IMPRECISE
ANT. 2/3 OF TONGUE
V3 - LINGUAL N.
PRECISE TOUCH
ANT. TO
EPIGLOTTIS X- VAGUS
IMPRECISE
PRECISE
SENSATION
POST. 1/3 OF
TONGUE IX - GLOSSOPHARYNGEAL
ANT. 2/3 OF
TONGUE
VII - CHORDA
TYMPANI
MOTOR - ALL MUSCLES INNERVATED BY XII HYPOGLOSSAL – TONGUE
DEVIATES TOWARD SIDE OF HYPOGLOSSAL LESION (GENIOGLOSSUS)