2 Welcome to the efferent system

3 ANATOMY OF THE ORBIT

4 ANATOMY OF ORBIT Seven bones make up the orbitRoof - frontal bone & the lesser wing of sphenoid Floor – maxilla, zygomatic bone, palatine bone Medial wall - maxilla, lacrimal bone, ethmoid , sphenoid Lateral wall - zygomatic, greater wing of sphenoid Medial walls are parallel, lateral walls form an angle of 900

6 ANATOMY OF EXTRAOCULAR MUSCLES

7 EXTRAOCULAR MUSCLES Six extraocular muscles4 recti- superior, inferior, medial, lateral 2 obliques – superior, inferior Inferior oblique- thinnest Medial rectus – largest

8 EXTRAOCULAR MUSCLES Recti run forward within sheaths , pierce the posterior tenon’s capsule & insert on the anterior sclera at points variably posterior to the corneal limbus – Spiral of Tillaux Tenon’s capsule - connective tissue that surrounds the eyeball & extends to the optic nerve.

9 EXTRAOCULAR MUSCLES Superior obliqueOrigin – Trochlea (pulley like structure) Runs anteriorly in the superior medial orbit to trochlea Tendon reverses direction Inferior oblique – anterior inferior medial periorbita near lacrimal fossa Both obliques insert on the posterior lateral aspect of globe behind the equator

10 EXTRAOCULAR MOVEMENTSDuctions - Monocular eye movements Versions - Movement of both eyes in the same direction Vergences are movements of the eyes in opposite directions Yoke muscles are the primary muscles in each eye that accomplish a given version (eg, for right gaze, the right lateral rectus and left medial rectus muscles)

11 ACTIONS OF EOMS Medial rectusAdducts the eye or moves eye towards the nose Lateral rectus Abducts the eye or moves the eye horizontally to the outside

12 ACTIONS OF EOMS Superior rectus Primary action –elevationSecondary action (globe adducted) – intortion, adduction Inferior rectus Primary action – depression Secondary action (globe adducted)- extortion, adduction

13 ACTIONS OF EOMS Superior oblique Primary action – intortion, abductionSecondary action (globe adducted) – depression Inferior oblique Primary action – extortion, abduction Secondary action (globe adducted)- elevation

14 INNERVATION 3rd cranial nerveSuperior division– levator, superior rectus, medial rectus Inferior division -inferior rectus, inferior oblique 4th cranial nerve – superior oblique 6th cranial nerve – lateral rectus

15 ANATOMY OF THE CAVERNOUS SINUS

16 CAVERNOUS SINUS Complex plexuses of veins in the duraLocated lateral to the sphenoid sinus Extends from the SOF to the apex of the petrous temporal bone Lateral wall of the sinus – III, IV & V1 nerve Internal carotid artery ,VI nerve (lateral) run in the sinus

17 PATHOLOGY

18 DIPLOPIA Reported as double vision or blurred visionDoes diplopia resolve when one eye is covered? Monocular vs binocular Is the diplopia horizontal,vertical or oblique? Is it same in all fields of gaze (comitant) or vary with gaze direction (incomitant) Is it constant, intermittent or variable?

19 DIPLOPIA Monocular- optical – refractive error, cataract, rarely maculopathy Binocular Orbital Mass Muscle Neuromuscular junction Nerve Cavernous sinus

20 ORBITAL MASS Intraconal Primary Cavernous hemangiomaOptic nerve glioma Optic nerve meningioma Rhabdomyosarcoma Orbital varices Metastatic lesions Breast Lung Prostate Neuroblastoma

21 ORBITAL MASS Extraconal Superior orbit (roof/frontal sinus)Dermoid tumor Mucocoele (frontal sinus) Orbital encephalocoele Fibrous dysplasia Lacrimal gland tumors

22 ORBITAL MASS Extraconal Inferior orbit (maxillary sinus/floor)Maxillary sinus mucocoele Fungal sinusitis Primary tumor (benign or malignant) Secondary tumor

23 ORBITAL MASS Extraconal Medial orbit (ethmoid /sphenoid sinus)Rhabdomyosarcoma Carcinoma of sinus Mucocoele

24 ORBITAL MASS Extraconal Lateral orbit (pterygopalatine fossa)Metastasis Pseudotumor of orbit Hemangioma Meningioma Rhabdomyosarcoma Arteriovenous malformations Encephalocoele Fibrous dysplasia Trauma with hemorrhage

25 MUSCLE Mechanical limitation of range of eye movementsThyroid associated orbitopathy Orbital myositis Orbital trauma Post – surgery restriction (cataract extraction) Genetic extraocular myopathy Congenital fibrosis syndrome Neoplastic infiltration Brown syndrome

26 NERVE 3rd cranial nerve Superior division – Levator, superior rectus, medial rectus Inferior division –inferior rectus, inferior oblique 4th cranial nerve – superior oblique 6th cranial nerve – lateral rectus Apex syndrome – CN 2, 3, 4, 6 all together

27 CAVERNOUS SINUS CN 3, 4, 6, V1, and sympatheticsWhen limited to 3, 4, 6 difficult to distinguish cavernous sinus from orbital apex Fifth nerve involvement – facial hypoaesthesia Sympathetic involvement - Horner’s syndrome

28 NEUROMUSCULAR JUNCTIONMyasthenia Gravis Fluctuating /variable ptosis or diplopia, ductional deficits Bilateral orbicularis weakness

35 DUANES RETRACTION SYNDROME TYPE 3Orthophoric in primary Limited abduction and adduction Palpebral fissure narrows and globe retracts on adduction No diplopia despite misalignment 35

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43 EOM METASTASIS FROM BREAST CANCERReview the PMH Orbital signs are not always present with an orbital process

44 ? A. Myasthenia B. 3rd nerve palsy C. TED D. Aberrant Regeneration 44

45 THYROID EYE DISEASE

47 SLEEP TEST – take a nap while you wait for the doctor

49 THANKYOU