The Orbital Apex the Orbital Apex • Review the Relationship Between the Orbital Apex and Adjacent Structures
Objectives
• Understand the anatomy of the orbital apex The Orbital Apex • Review the relationship between the orbital apex and adjacent structures
Barry Shpizner, MD • Discuss the imaging features of the orbital LIJ Medical Center apex in relation to adjacent anatomic Northwell Health structures New Hyde Park, NY
Bony Anatomy Acknowledgments Orbit • Frontal • Richard Wiggins, MD • Zygomatic • Claudia Kirsch, MD • Maxillary • Lacrimal • Ethmoid • Palatine • Sphenoid
Bony Anatomy Orbital Apex Bony Anatomy
•OPTIC CANAL/OPTIC FORAMEN
•POSTEROR ETHMOID FORAMEN
From Osseous Anatomy of the Orbital Apex David L. Daniels, et. al. AJNR 16:1929–1935, Oct 1995 0195-6108/95/1609–1929 Cavernous Sinus Optic Strut
Superior Orbital Fissure Pterygopalatine Fossa
Inferior Orbital Fissure Optic Canal Optic Strut Superior Orbital Fissure
Inferior Orbital Fissure Annulus of Zinn
Cranial Nerve II Annulus of Zinn Optic Nerve OCULOMOTOR FORAMEN- within annulus OPTIC TRACTS •OPTIC FORAMEN OPTIC CHIASM CN II SEGMENTS ) CN II Ophthalmic artery •Intracranial •Central Superior Orbital Fissure •Intracanalicular CN III •Intraorbital Nasociliary n. CN V1 •Intraocular- CN VI papilla SOF ABOVE ANNULUS CN V1 branches Acquires dural CN IV covering entering Superior ophth. vein optic canal SOF BELOW ANNULUS Inferior ophth. vein
Optic Canal
RICK
Optic Nerve Cranial Nerve III Oculomotor Foramen Oculomotor Nerve NUCLEI- within ventral periaqueductal grey
•Oculomotor n.- motor fibers to extraocular muscles except SO and LR
•Edinger - Westphal n.- parasympathetic fibers via ciliary ganglion produce pupillary constriction and accomodation
Cranial Nerve III Oculomotor Nerve
Exits via interpeduncular cistern
Courses between PCA and SCA
Enters oculomotor cistern
Cavernous sinus
Cranial Nerve III Cranial Nerve III Oculomotor Nerve Enters through SOF Within lateral wall of oculomotor foramen cavernous sinus SUPERIOR DIVISION Superior most nerve •Levator palpebrae •Superior rectus Other cranial nerves within lateral wall INFERIOR DIVISION IV •Medial rectus V1 •Inferior rectus V2 •Inferior oblique •Ciliary ganglion
Cranial Nerve IV Cranial Nerve IV Trochlear Nerve Trochlear Nerve NUCLEUS in periaquductal grey
Fibers decussate and exit dorsal midbrain below inferior Courses within lateral wall colliculus of cavernous sinus
Courses between PCA and SCA First below and more
Enters cavernous sinus anteriorly above CN III
Long intracranial course Above V1 (ophthalmic n.) predisposes to injury from blunt trauma
Cranial Nerve III Cranial Nerve IV Cranial Nerve IV Cranial Nerve V Trigeminal Nerve SENSORY NUCLEI- from face
PROPRIOCEPTION
TOUCH
PAIN AND TEMPERATURE
Cranial Nerve V Cranial Nerve V To Orbit CISTERNAL SEGMENT Prepontine cistern GASSERIAN GANGLION Meckel’s cave OPHTHALMIC NERVE- V1 MAXILLARY NERVE- V2 Cavernous sinus OPHTHALMIC NERVE Superior orbital fissure MAXILLARY NERVE Foramen rotundum Cisternal Meckel’s Cave
Cranial Nerve V1 Cranial Nerve V Ophthalmic Nerve Orbital Branches
OPHTHALMIC NERVE (V1) SUPERIOR ORBITAL FISSURE Above annulus of Zinn • Lacrimal nerve • Frontal nerve – Supratrochlear nerve – Supraorbital nerve Within annulus of Zinn • Nasociliary nerve- Sensation to eye through ciliary ganglion and long ciliary nerves Sensation to nasal cavity and nose through ethmoidal foraminal branches
Cranial Nerve V2 Cranial Nerve V Maxillary Nerve Orbital Branches MAXILLARY NERVE (V2) FORAMEN ROTUNDUM PTERYOPALATINE FOSSA Small branches to/from pterygopalatine ganglion INFERIOR ORBITAL FISSURE • Zygomatic nerve -sensation to face and anastomotic parasympathetic branches to lacrimal gland • Infraorbital nerve- sensation to lower lid, cheek and lip.
Cranial Nerve VI Cranial Nerve VI Abducens Nerve NUCLEUS- within pons ventral to 4th ventricle
CN 7 loops around CN VI nucleus forming a bulge in the floor of ventricle (facial colliculus)
Exits at pontomedullary junction
Cisternal segment ascends to enter Dorello’s canal
Courses through cavernous sinus
Enters orbit through SOF within common tendinous ring Only nerve within the substance of the cavernous sinus
Cranial Nerve VI
Ophthalmic artery Ophthalmic artery Ophthalmic artery •Lacrimal artery •Lacrimal artery •Short posterior ciliary arteries
Ophthalmic artery Ophthalmic artery •Lacrimal artery •Lacrimal artery •Short posterior ciliary •Short posterior ciliary arteries arteries •Posterior ethmoidal artery •Posterior ethmoidal artery •Anterior ethmoidal artery
Summary
Superior ophthalmic vein OCULOMOTOR FORAMEN (WITHIN ZINN) •Lacrimal vein Optic nerve •Short posterior ciliary veins Ophthalmic artery •Posterior ethmoidal vein SUPERIOR ORBITAL FISSURE CENTRAL COMP. • Anterior ethmoidal vein CN III Superior and inferior divisions CN V1 Nasociliary nerve CN VI
Summary
SUPERIOR ORBITAL FISSURE ABOVE ZINN CN V1 Lacrimal and frontal nerves CN IV Superior ophthalmic vein SUPERIOR ORBITAL FISSURE BELOW ZINN Inferior ophthalmic vein branch
INFERIOR ORBITAL FISSURE CN V2 Infraorbital and Zygomatic nerves Inferior ophthalmic vein branch