Major Anatomic Components of the Orbit 1. Osseous Framework 2. Globe 3. Optic nerve and sheath 4. Extraocular muscles
Bony Orbit Seven Bones Frontal bone Zygomatic bone Maxillary bone Ethmoid bone Sphenoid bone Lacrimal bone Palatine bone
Bony Orbit Divisions Orbital roof Orbital floor Medial orbital wall Lateral orbital wall Bones Frontal Sphenoid Zygomatic Maxillary Mandible Lacrimal Ethmoid Palatine
Bony Orbit Supraorbital Foramen Frontal Bone Coronal View
Bony Orbit Frontal Bone Lacrimal bone Maxillary Bone Coronal View
Bony Orbit Frontal Bone Ethmoid Bone Zygomatic Bone Maxillary Bone Coronal View
Bony Orbit Frontal Bone Sphenoid Bone Coronal View
Bony Orbit Frontal Bone Axial View
Bony Orbit Zygomatic Bone Ethmoid Bone Sphenoid Bone Axial View
Bony Orbit Zygomatic Bone Maxillary Bone Axial View
Bony Orbit: X-Ray
Bony Orbit: X-Ray
Orbital Fissures/Foramen Anterior Clinoid Foramen Rotundum Pterygoid (Vidian) Canal Axial View Coronal View
Orbital Fissures/Foramen Anterior Clinoid Foramen Rotundum Pterygoid (Vidian) Canal Axial View Pterygoid Plates Coronal View
Orbital Fissures/Foramen Anterior Clinoid Optic Canal Superior Orbital Fissure Foramen Rotundum Pterygoid (Vidian) Canal Axial View Coronal View
Orbital Fissures/Foramen Optic Canal Anterior Clinoid Superior Orbital Fissure Foramen Rotundum Axial View Coronal View
Orbital Fissures/Foramen Optic Canal Anterior Clinoid Superior Orbital Fissure PPF Axial View PPF = Pterygopalatine fossa Coronal View
Orbital Fissures/Foramen Superior Orbital Fissure IOF Axial View IOF = Inferior orbital fissure Coronal View
Orbital Fissures/Foramen IOF Axial View IOF = Inferior orbital fissure Coronal View
Orbital Fissures/Foramen IOF Axial View IOF = Inferior orbital fissure Coronal View
Orbital Fissures/Foramen Infraorbital Canal Axial View Coronal View
Orbital Fissures/Foramen Infraorbital Canal Axial View Coronal View
Orbital Fissures/Foramen Infraorbital Canal Axial View Coronal View
Extraocular Muscles and CN innervation Superior Rectus: III Inferior Rectus: III Medial Rectus: III Lateral Rectus: VI Superior oblique: IV Inferior oblique: III Levator palpebrae: III
Extraocular Muscles Superior Rectus/ Levator Axial View Lateral Rectus Inferior Rectus Medial Rectus Coronal View
Extraocular Muscles Superior Rectus/ Levator Lateral Rectus Medial Rectus Axial View Lateral Rectus Inferior Rectus Medial Rectus Coronal View
Extraocular Muscles Superior Rectus/ Levator Superior Oblique Axial View Superior Medial Oblique Rectus Coronal View
Extraocular Muscles Superior Oblique Superior Rectus/ Levator Axial View Superior Medial Oblique Rectus Coronal View
Extraocular Muscles Sagittal View
Cranial Nerve II: Optic Nerve Optic Canal Optic Nerve Origin: Globe Course: Orbit, Optic Canal, Optic Chiasm, Tract, Thalamus Not a true Cranial Nerve: Extension of the diencephalon
Optic Canal Anterior Clinoid Optic Canal
Cranial Nerve III: Oculomotor Nerve Origin: Midbrain Course: Cistern (passes between posterior cerebral artery and superior cerebellar artery) Cavernous sinus Superior Orbital Fissure CN III Cerebral Peduncle Orbit Exit Skull base: Superior Orbital Fissure
Cranial Nerve III: Oculomotor Nerve Cavernous Sinus CN III Origin: Midbrain Course: Cistern (passes between posterior cerebral artery and superior cerebellar artery) Cavernous sinus Superior Orbital Fissure Orbit Exit Skull base: Superior Orbital Fissure
Cranial Nerve IV: Trochlear Nerve Origin: Posterior Midbrain Course: Posterior origin Travels anteriorly through cistern Cavernous sinus Superior orbital fissure Orbit Innervation: Superior Oblique Muscle
Cranial Nerve V: Trigeminal Nerve CN V Origin: Pons Course: Cistern Trigeminal ganglion Divides into (3) branches: V1 Ophthalmic, V2 Maxillary, V3 Mandibular V1 and V2 pass through the cavernous sinus before exiting the skull. V3 does not pass through the cavernous sinus
V1:Superior Orbital Fissure Anterior Clinoid Process Optic Canal SOF Superior Orbital Optic Canal Fissure Anterior Clinoid Process
V2: Foramen Rotundum Foramen Rotundum
V2: Inferior Orbital Fissure
V2: Infraorbital Canal/Foramen
V3: Foramen Ovale Foramen Spinosum Foramen Ovale
V3: Foramen Ovale
Cranial Nerve VI: Abducens Nerve Origin: pontomedullary junction Course: Cistern Cavernous sinus Superior orbital fissure Orbit Innervation: Lateral rectus muscle
Lacrimal Gland Lacrimal Gland
Vascular Supply to Orbit Ophthalmic Arteries Superior Ophthalmic Vein
Squamous Portion Zygomatic Process Tympanic Portion Mastoid Portion
Zygomatic Process Tympanic Portion Axial View
Squamous Portion Petrous Portion Axial View Mastoid Portion
Styloid Process Coronal View
External Auditory Canal EAC EAC Coronal View EAC = External Auditory Canal Tympanic Membrane Axial View
Ossicles Malleus Incus Malleus Tympanic Membrane Articulates with the incus Incus Articulates with the malleus and stapes Stapes Stapes Angled Coronal View Tympanic Membrane Articulates with the incus Oval Window
Ossicles Malleus Incus Axial View
Ossicles Malleus Stapes Oval Window Incus Axial View
MRI: Axial View Cochlea CT: Axial View CT: Coronal View
Semicircular Canals Lateral SCC MRI: Axial View CT: Axial View
Semicircular Canals CT: Coronal View Anterior (Superior) SCC Posterior SCC
Semicircular Canals CT: Coronal View Anterior (Superior) SCC Posterior SCC
Cranial Nerves VII: Facial Nerve Origin: Pontomedullary junction Course: 6 Segments Cisternal Intracanalicular Labyrinthine Tympanic Mastoid Extracranial Branches: GPN, Chorda Tympani, Stapedius, Muscles of facial expression
Internal Auditory Canal (IAC) Internal Auditory Canal Internal Auditory Canal
Cisternal and Intracanalicular Vestibulocochlear Nerve Facial Nerve Sup Vestib Nerve Cochlear Nerve Inf Vestib Nerve
Geniculate Ganglion Geniculate Ganglion Greater Petrosal Nerve Tympanic Segment Facial Nerve
Tympanic Segment Facial Nerve Tympanic Segment
Mastoid Segment Facial Nerve Mastoid Segment
Mastoid Segment Facial Nerve Stylomastoid Foramen
CN VIII: Vestibulocochlear Nerve Sensory Nerve Cochlea: Cochlear division (hearing) Vestibular division (balance): Semicircular canals Course: Internal Auditory Canal Cistern Pontomedullary junction
Intracanalicular Facial Nerve Porus Acusticus Anterior Posterior Facial Nerve 7-up, Coke down Cochlear Nerve Superior Vestibular Nerve Inferior Vestibular Nerve IAC