FOCUSED REVIEW: AUTONOMIC INNERVATION OF THE EYE AND ORBIT I. ORBIT - eyelid; lacrimal gland II. EYE - pupil; lens

Autonomic Nervous system = Visceral nervous system - involuntary, unconscious part of nervous system; control smooth and cardiac muscle, glands and internal organs: two neuron pathway AUTONOMIC = VISCERAL NERVOUS SYSTEM EYE PARASYMPATHETICS - cranio- sacral - ganglia close totarget organ SYMPATHETICS - thoraco-lumbar - many ganglia in sympathetic chain CNS Preganglionic Neuron Postganglionic Neuron GANGLION smooth muscle, gland SYMP. PARASYMP.

SYMPATHETICS IN THORAX, ABDOMEN: Thoraco-Lumbar T1-T12, L1(2) SYMPATHETICS TO HEAD: leave cord at T1, T2 - Postganglionic fiber leaves via grey communicating ramus to innervate target - Preganglionic neuron in spinal cord at T1, T2 - leaves and ascends sympathetic chain - Preganglionic neuron in spinal cord, enters white communicating ramus and synapses in sympathetic ganglion Clinical: Compression of sympathetic chain in neck can produce symptoms in head due to compression of ascending sympathetic pre-ganglionic fibers

SYMPATHETICS TO HEAD Second neuron In Superior Cervical Ganglia Joins Plexus on Internal and External Carotid Arteries (mostly unnamed branches) NERVE PLEXUS ON CAROTID ARTERIES 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 +palate III VII IX X

1) EYELID - Levator Palpebrae Superioris lifts eyelid - consists of skeletal and smooth muscle; skeletal muscle - CN III; smooth muscle from sympathetics 2) LACRIMAL GLAND - innervated by parasympathetics from CN VII 3) in EYE - Pupil - Constrictor - Parasympathetics from CN III Dilator - Sympathetics Ciliary muscle - controls lens - Parasympathetics from CN III

LEVATOR PALPEBRAE TARSAL PLATE LEVATOR PALPEBRAE SUPERIORIS MUSCLE - ORIGIN FROM TENDINOUS RING - COMPOSED OF SKELETAL (CN III) & SMOOTH (SYMPATHETICS) MUSCLE PARTS MUSCLE OF EYELID: LEVATOR PALPEBRAE SUPERIORIS DAMAGE INNERVATION PTOSIS = DROOPING EYELID skeletal muscle III smooth muscle sympathetics

OCULOMOTOR NERVE PALSY other symptoms: - Pupil is dilated - denervate pupillary constrictor (mydriasis) - Also affect Eye movements - Accomodation SYMPATHETICS - HORNER'S SYNDROME - - Miosis - constricted pupil - Anhydrosis - lack of sweating SKELETAL MUSCLE PART PTOSIS = DROOPING EYELID; CAN BE SIGN OF DAMAGE TO OCULOMOTOR NERVE (III) OR SYMPATHETICS SMOOTH MUSCLE PART

- 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 AUTONOMIC PARASYMPATHETICS TO LACRIMAL GLAND LACRIMAL PUNCTUM SAC LACRIMAL GLAND - LOCATED IN SUPEROLATERAL ORBIT - OPENS BY DUCTS (~12) THROUGH CONJUNCTIVA TO SUPERIOR FORNIX - TEARS CONSTANTLY PRODUCED

1) leaves Facial canal and forms N. Of Pterygoid Canal; ends (synapses) in PterygoPalatine Ganglion VII PARASYMPATHETIC PATHWAY OF VII TO LACRIMAL GLAND 2) Post ganglionic fibers distributed (hitchhike) with BRANCHES OF V1 AND V2 V1 LACRIMAL N. V2 ZYGOMATIC N. PTERYGOPALATINE GANGLION LACRIMAL GLAND V2 Greater Petrosal N. Clinical - Damage to VII can affect tear production in lacrimal gland

IRIS - PIGMENTED, CONTRACTILE LAYER SURROUNDING PUPIL PUPIL DILATOR PUPIL M.- RADIAL SMOOTH MUSCLE; SYMPA- THETICS CONSTRICTOR PUPIL M. - CIRCULAR SMOOTH MUSCLE; PARA- SYMPATHETICS III AUTONOMICS TO SMOOTH MUSCLES OF EYE PUPIL IRIS - PIGMENTED

CILIARY MUSCLES- SMOOTH MUSCLES CONTRACT PRODUCE - RELAXATION OF LIGAMENTS - THICKENING LENS ACCOMODATION- THICKEN LENS FOR NEAR VISION; PARASYMPATHETIC CONTROL- III (CILIARY GANGLION) CILIARY MUSCLES PARASYMPATHETIC MECHANISM OF ACCOMODATION SUSPENSORY LIGAMENTS OF LENS CILIARY BODY - ATTACHES SUSPENSORY LIGAMENTS OF LENS CONTAINS CILIARY MUSCLES

CAVERNOUS SINUS 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 Pituitary stalk OPHTHALMIC VEINS

Anastomoses of Facial and Ophthalmic Vv. - Ophthalmic veins drain to cavernous sinus (venous sinus inside skull) OPHTHALMIC VEIN 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 NOSE PTERYGOID VENOUS PLEXUS FACIAL VEIN SPREAD OF INFECTION FROM FACE TO BRAIN

PITUITARY CAV. SINUS INTERNAL CAROTID III IV V1,V2 VI 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 CRANIAL NERVES AND CAROTID ARTERY PASS THROUGH WALL OF CAVERNOUS SINUS

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 III, IV, V1, V2, and VI and Sympathetic fibers to orbit (travel on Internal Carotid) SPREAD OF INFECTION TO CAVERNOUS SINUS

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) 2) V1, V2 Facial pain (pressure on nerves) 3) Sympathetics on Internal Carotid Ptosis (drooping eyelid) Miosis (constricted pupil) SPREAD OF INFECTION TO CAVERNOUS SINUS

GOOD LUCK!