Transcript Autonomic_Innervation_of_Eye_and_Orbit_2012

FOCUSED REVIEW: AUTONOMIC
INNERVATION OF THE EYE AND
ORBIT
I. ORBIT - eyelid; lacrimal gland
II. EYE - pupil; lens
AUTONOMIC = VISCERAL NERVOUS SYSTEM
PARASYMP.
EYE
Autonomic Nervous system =
Visceral nervous system involuntary, unconscious part of
nervous system; control smooth and
cardiac muscle, glands and internal
organs: two neuron pathway
Preganglionic
Neuron
SYMP.
Postganglionic
Neuron
smooth
muscle,
gland
CNS
GANGLION
PARASYMPATHETICS - craniosacral - ganglia close to target
organ
PARASYMP.
SYMPATHETICS - thoraco-lumbar
- many ganglia in sympathetic
chain
SYMPATHETICS IN
THORAX, ABDOMEN:
Thoraco-Lumbar
T1-T12, L1(2)
- Preganglionic neuron in
spinal cord, enters
white communicating
ramus and synapses in
sympathetic ganglion
- Postganglionic fiber
leaves via grey
communicating ramus
to innervate target
SYMPATHETICS TO HEAD:
leave cord at T1, T2
- Preganglionic neuron in
spinal cord at T1, T2
- leaves and ascends
sympathetic chain
Clinical: Compression of sympathetic chain in
neck can produce symptoms in head due to
compression of ascending sympathetic
pre-ganglionic fibers
SYMPATHETICS TO HEAD
NERVE PLEXUS
ON
CAROTID
ARTERIES
Second neuron In
Superior
Cervical Ganglia
Joins Plexus on
Internal and
External
Carotid Arteries
(mostly unnamed
branches)
SCG SUPERIOR
CERVICAL
GANGLION
Superior Cervical Ganglion
is located at base of skull, posterior to
Carotid sheath, below Jugular
Foramen, lateral to Retropharyngeal
space;
PARASYMPATHETICS - IN CRANIAL NERVES
III
VII
IX
X
+palate
2) LACRIMAL GLAND innervated by parasympathetics
from CN VII
1) EYELID - Levator Palpebrae Superioris
lifts eyelid - consists of skeletal and smooth
muscle; skeletal muscle - CN III; smooth
muscle from sympathetics
3) in EYE - Pupil - Constrictor - Parasympathetics from CN III
Dilator - Sympathetics
Ciliary muscle - controls lens - Parasympathetics from CN III
MUSCLE OF EYELID: LEVATOR PALPEBRAE SUPERIORIS
LEVATOR
PALPEBRAE
skeletal muscle III
smooth muscle
sympathetics
TARSAL
PLATE
LEVATOR PALPEBRAE SUPERIORIS MUSCLE - ORIGIN FROM
TENDINOUS RING - COMPOSED OF SKELETAL (CN III) & SMOOTH
(SYMPATHETICS) MUSCLE PARTS
DAMAGE INNERVATION PTOSIS = DROOPING EYELID
PTOSIS = DROOPING
EYELID; CAN BE SIGN
OF DAMAGE TO
OCULOMOTOR NERVE
(III) OR
SYMPATHETICS
SKELETAL MUSCLE PART
OCULOMOTOR NERVE PALSY
other symptoms:
- Pupil is dilated - denervate
pupillary constrictor (mydriasis)
- Also affect Eye movements
- Accomodation
SMOOTH MUSCLE PART
SYMPATHETICS - HORNER'S
SYNDROME - Miosis - constricted pupil
- Anhydrosis - lack of sweating
AUTONOMIC PARASYMPATHETICS TO LACRIMAL GLAND
LACRIMAL GLAND - LOCATED IN SUPEROLATERAL ORBIT - OPENS
BY DUCTS (~12) THROUGH CONJUNCTIVA TO SUPERIOR FORNIX TEARS CONSTANTLY PRODUCED
SAC
LACRIMAL
PUNCTUM
- TEARS DRAIN THROUGH LACRIMAL PUNCTA TO LACRIMAL SAC TO
NASOLACRIMAL DUCT TO INFERIOR MEATUS OF NASAL CAVITY
B. LAC. GLAND INNERVATED BY VII- COMPLEX PATHWAY
PARASYMPATHETIC PATHWAY OF VII TO LACRIMAL
GLAND
1) leaves Facial canal and forms N. Of Pterygoid Canal; ends
(synapses) in PterygoPalatine Ganglion
2) Post ganglionic fibers distributed (hitchhike) with
BRANCHES OF V1 AND V2
V1 LACRIMAL N.
Greater Petrosal N.
V2 ZYGOMATIC N.
V2
PTERYGOPALATINE
GANGLION
VII
Clinical - Damage to VII can affect
tear production in lacrimal gland
LACRIMAL GLAND
AUTONOMICS TO SMOOTH MUSCLES OF EYE
DILATOR
PUPIL M.RADIAL
SMOOTH
MUSCLE;
SYMPATHETICS
IRIS - PIGMENTED,
CONTRACTILE LAYER
SURROUNDING PUPIL
IRIS - PIGMENTED
PUPIL
PUPIL
CONSTRICTOR
PUPIL M. CIRCULAR
SMOOTH
MUSCLE;
PARASYMPATHETICS
III
PARASYMPATHETIC MECHANISM OF ACCOMODATION
SUSPENSORY LIGAMENTS OF LENS
ACCOMODATIONTHICKEN LENS FOR
NEAR VISION;
PARASYMPATHETIC
CONTROL- III
(CILIARY GANGLION)
CILIARY
BODYATTACHES
SUSPENSORY
LIGAMENTS
OF LENS
CONTAINS
CILIARY
MUSCLES
CILIARY MUSCLES
CILIARY
MUSCLESSMOOTH
MUSCLES
CONTRACT
PRODUCE
- RELAXATION
OF LIGAMENTS
- THICKENING
LENS
CAVERNOUS SINUS
OPHTHALMIC VEINS
Pituitary
stalk
Cavernous sinuses - in
middle cranial fossa; on
side of the body of the
sphenoid bone; receive
blood from Sup. and Inf.
Ophthalmic veins; drain to
Sup. and Inf. Petrosal
sinuses
Sup. and Inf. Petrosal sinuses on petrous part of temporal bone
SPREAD OF INFECTION FROM FACE TO BRAIN
Anastomoses
of Facial and
Ophthalmic Vv.
- Ophthalmic
veins drain to
cavernous
sinus (venous
sinus inside
skull)
OPHTHALMIC
VEIN
NOSE
FACIAL
VEIN
PTERYGOID VENOUS PLEXUS
CLINICAL: Prolonged infection on face (lateral to nose) produces 'Blurred
vision' (Diplopia); Prolonged infections spread via veins (pressure low, no
valves) through orbit via Ophthalmic Veins to Cavernous Sinus;
- Infections lateral to nose particularly dangerous; also infections from teeth
can spread through pterygoid venous plexus
CRANIAL NERVES AND CAROTID ARTERY PASS THROUGH WALL OF CAVERNOUS SINUS
STRUCTURES PASSING THROUGH WALL OF CAVERNOUS
SINUS - Int. Carotid A., Cranial N.'s III, IV, V1, V2, VI;
SYMPTOM of Infection in Sinus – ‘BLURRED’ VISION; not affect CN II
no direct
effect on
II
INTERNAL
CAROTID
PITUITARY
CAV.
SINUS
III
IV
V1,V2
VI
CAVERNOUS SINUS SYNDROME
CAUSES
1) Aneurysm of the
internal carotid artery in
the cavernous sinus,
2) Infection or venous
thrombus (blood clot) in
cavernous sinus, or by
3) Pituitary tumor
encroaching into sinus.
NERVES EFFECTED
SPREAD OF INFECTION TO
CAVERNOUS SINUS
III, IV, V1, V2, and VI and
Sympathetic fibers to orbit
(travel on Internal Carotid)
CAVERNOUS SINUS SYNDROME SYMPTOMS
1) III
- Ocular palsy (impaired eye
movement)
- Damage III - Dilated pupil (paralyze
constrictor)
- No pupillary light reflex (paralyze
pupillary constrictor)
- No accommodation (paralyze
ciliary muscle)
- Ptosis (drooping eyelid, paralyze
levator palpebrae superioris)
SPREAD OF INFECTION TO
CAVERNOUS SINUS
2) V1, V2
Facial pain (pressure on nerves)
3) Sympathetics on Internal Carotid
Ptosis (drooping eyelid)
Miosis (constricted pupil)
GOOD LUCK!