HN [7: Orbital.2 and Lacrimal Gland]

Frontal ethmoidal suture

Location where the ethmoidal foramina can be seen

Anterior and posterior ethmoidal foramina

Components of the ethmoidal foramina

Anterior and posterior ethmoidal foramina

Serve as surgical landmarks to assess the surgeon’s depth inside the orbit

Anterior and posterior ethmoidal foramina

Exit location of anterior and posterior ethmoidal arteries

Anterior and posterior ethmoidal foramina

Possible routes of entry for infections or neoplasms into the orbital area

Orbital cellulitis

Bacterial infection of the fat and/or muscles around the eye

Orbital cellulitis

Characterized by visible mass or swelling extending around the orbit, ophthalmoplegia, and proptosis

Orbital cellulitis

May spread to adjacent anatomical structures if left untreated

Orbital cellulitis

Typically treated with a broad

Superior orbital fissure

Separates the greater and lesser wings of the sphenoid bone

CN III (Oculomotor nerve), CN IV (Trochlear nerve), CN VI (Abducens nerve), CN V1 (Ophthalmic branch of the trigeminal nerve), sympathetic fibers, superior ophthalmic vein

Structures transmitted through the superior orbital fissure

Frontal ethmoidal suture

Location where the ethmoidal foramina can be seen

Anterior and posterior ethmoidal foramina

Components of the ethmoidal foramina

Anterior and posterior ethmoidal foramina

Serve as surgical landmarks to assess the surgeon’s depth inside the orbit

Anterior and posterior ethmoidal arteries

Pass through the corresponding ethmoidal foramina

Anterior and posterior ethmoidal foramina

Possible routes of entry for infections or neoplasms into the orbital area

Orbital cellulitis

Bacterial infection of the fat and/or muscles around the eye

Orbital cellulitis

Characterized by visible mass or swelling extending around the orbit, ophthalmoplegia, and proptosis

Orbital cellulitis

May spread to adjacent anatomical structures if left untreated

Orbital cellulitis

Typically treated with a broad

Superior orbital fissure

Separates the greater and lesser wings of the sphenoid bone

CN III (Oculomotor nerve), CN IV (Trochlear nerve), CN VI (Abducens nerve), CN V1 (Ophthalmic branch of the trigeminal nerve), sympathetic fibers, superior ophthalmic vein

Structures transmitted through the superior orbital fissure

Annulus of Zinn

Fibrous ring forming the common origin of the four recti muscles of the eye

Annulus of Zinn

Encircles the optic foramen and central portion of the superior orbital fissure

Annulus of Zinn

Superior portion of the superior orbital fissure

Annulus of Zinn

Transmits the trochlear nerve (CN IV) and frontal and lacrimal branches of V1

Oculomotor foramen

Area of the superior orbital fissure encircled by the annulus of Zinn

Oculomotor foramen

Transmits CN III, CN VI, nasociliary branch of V1, superior ophthalmic vein, and sympathetic nerve plexus

Trochlear nerve (CN IV)

Only nerve listed in the superior orbital fissure contents that does not pass through the annulus of Zinn

Inferior orbital fissure

Bounded by the sphenoid, maxillary, and palatine bones

Inferior orbital fissure

Associated with CN V2 and its zygomatic and infraorbital nerve branches

Infraorbital nerve

Travels through the foramen rotundum to the pterygopalatine fossa, then enters the orbit through the inferior orbital fissure and infraorbital groove

Infraorbital nerve

Exits through the infraorbital foramen on the maxilla, approximately 1 cm below the orbital rim

Infraorbital nerve

Provides sensation to the lower eyelid, cheek, upper lip, and upper teeth

Infraorbital nerve injury

Can result in hypoesthesia in the areas supplied by the nerve

Zygomaticofacial, Zygomaticotemporal foramina

Transmit vessels and nerves of the zygoma

Zygomatic nerves

Provide sensation to the cheek and temporal area

Nasolacrimal canal

Extends from the lacrimal sac fossa to the inferior meatus

Nasolacrimal canal

Nasolacrimal duct Passes through

Optic canal

Located at the lesser wing of the sphenoid bone

Optic canal

Transmits CN II (optic nerve), ophthalmic artery, and sympathetic nerves

Optic nerve glioma

Tumorous growth around the optic nerve that causes optic nerve expansion and widening of the optic canal

Ophthalmic artery

Major blood supply to the orbit; branch of the internal carotid artery

Optic canal

Passage through which the ophthalmic artery travels beneath the intracranial optic nerve and through the dura mater to enter the orbit

Branches to the extraocular muscles (EOMs), central retinal artery, and posterior ciliary arteries

Major branches of the ophthalmic artery

Central retinal artery

Supplies the optic nerve and retina

Short ciliary branches

Branches of the posterior ciliary arteries that supply the choroid

Long ciliary branches

Branches of the posterior ciliary arteries that supply the anterior segment of the eye

Superior ophthalmic vein

Major venous drainage of the orbit

Superior ophthalmic vein

Drains through the superior orbital fissure into the cavernous sinus

Superior ophthalmic vein

Starts from the superonasal quadrant and extends posteriorly through the superior orbital fissure into the cavernous sinus

Superior ophthalmic vein

The only structure noted radiographically to course diagonally through the superior orbit

V1

Ophthalmic division of the trigeminal nerve that supplies sensory innervation to the orbit

Frontal nerve

Travels through the superior portion of the superior orbital fissure, penetrates extraconal fat, and supplies the supratrochlear region

Supratrochlear region

Includes the medial forehead, medial canthus, and frontal scalp; supplied by the frontal nerve

Lacrimal nerve

Travels through the superior portion of the superior orbital fissure and supplies the lacrimal region, including the upper eyelid, forehead, and lacrimal glands

Nasociliary nerve

Passes through the oculomotor foramen and enters the intraconal space

Nasociliary nerve

Supplies the supraorbital region

Short ciliary nerves

Formed from the ciliary ganglion and have synapsed to the sclera

Long ciliary nerves

Travel anteriorly to innervate the cornea, iris, and ciliary muscles

V2

Maxillary division of the trigeminal nerve that supplies the infraorbital region

V2

Innervates the lower eyelid, nose, cheek, and upper lip

V3

Mandibular division of the trigeminal nerve

Herpes zoster ophthalmicus

Reactivation of a dormant virus during an immunosuppressed period that follows the distribution of the affected sensory nerve

Herpes zoster ophthalmicus

Nasal involvement usually indicates concomitant intraocular inflammation leading to uveitis

CN III

Oculomotor nerve; main motor nerve to the eye

CN IV

Trochlear nerve; supplies the superior oblique muscle

CN VI

Abducens nerve; supplies the lateral rectus muscle

CN VII

Facial nerve; supplies muscles of facial expression and the eyelids

Orbicularis oculi, Procerus, Corrugator Superciliaris, Frontalis

Muscles supplied by the facial nerve

Parasympathetic innervation

Responsible for accommodation, pupil constriction, and lacrimation

Accommodation

Distance focusing mediated by parasympathetic innervation

Pupil constriction

Light gating mediated by parasympathetic innervation

Lacrimation

Tearing up mediated by parasympathetic innervation

Sympathetic innervation

Responsible for pupil dilation, vasoconstriction, smooth muscle function of the eyelids, and hidrosis

Horner’s syndrome

Denervation of the sympathetic innervation of the face

Horner’s syndrome

Causes ptosis, miosis, and anhidrosis

Ptosis

Drooping eyelid associated with Horner’s syndrome

Miosis

Narrowed pupil associated with Horner’s syndrome

Anhidrosis

Lack of sweating associated with Horner’s syndrome

Horner’s syndrome

May also cause lower eyelid elevation

Lacrimal gland

Located in the shallow depression within the orbital depression of the frontal bone

Lacrimal gland

Divided by the lateral horn of the levator muscle into the orbital lobe and palpebral lobe

Orbital

Lobe of the lacrimal gland that empties into the superior temporal fornix

Palpebral

Lobe of the lacrimal gland found at the superolateral conjunctival fornix when the upper eyelid is everted

6 weeks after birth

When the lacrimal gland becomes functional

Superior cul

de

CN V

Afferent nerve for lacrimation

CN VII

Efferent nerve for lacrimation

Lacrimal drainage system

Prevents tears from overflowing

Punctum

Opening of the lacrimal drainage system measuring approximately 2 mm

Valve of Rosenmüller

Prevents backflow in the lacrimal drainage system

Lacrimal sac, measures approximately 10 mm

Nasolacrimal duct

Measures approximately 10–12 mm and drains tears into the inferior meatus of the nose

Valve of Hasner

Located at the opening of the nasolacrimal duct into the inferior meatus

Inferior meatus of the nose

Where tears drain into the nose, causing sniffles when crying

Superior and inferior puncta → superior and inferior canaliculi → common canaliculus → lacrimal sac → nasolacrimal duct → inferior meatus of the nose

Tear Flow

Dacryocystitis

Inflammation caused by tear and mucus stasis, which leads to bacterial infection

Dacryocystitis

Manifests as tearing, mucopurulent discharge, and a tender medial mass full of pus

Acquired

Dacryocystitis that typically affects the elderly population, especially menopausal females