FOCUSED REVIEW AUTONOMIC INNERVATION OF THE EYE AND

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 CNS GANGLION PARASYMPATHETICS - craniosacral - ganglia close to target organ PARASYMP. SYMPATHETICS - thoracolumbar - many ganglia in sympathetic chain smooth muscle, gland

SYMPATHETICS IN THORAX, ABDOMEN: Thoraco-Lumbar T 1 -T 12, L 1(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 T 1, T 2 - Preganglionic neuron in spinal cord at T 1, T 2 - 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 - 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 Pterygo. Palatine Ganglion 2) Post ganglionic fibers distributed (hitchhike) with BRANCHES OF V 1 AND V 2 V 1 LACRIMAL N. Greater Petrosal N. V 2 ZYGOMATIC N. V 2 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 CONSTRICTOR PUPIL M. CIRCULAR SMOOTH MUSCLE; PARA SYMPATHETICS 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 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 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, V 1, V 2, VI; SYMPTOM of Infection in Sinus – ‘BLURRED’ VISION; not affect CN II no direct effect on II INTERNAL CAROTID PITUITARY CAV. SINUS III IV V 1, V 2 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, V 1, V 2, 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) V 1, V 2 Facial pain (pressure on nerves) 3) Sympathetics on Internal Carotid Ptosis (drooping eyelid) Miosis (constricted pupil)

GOOD LUCK!