Eyelids: Located in the front of the orbit and covering the surface of the eyeball, they are divided into upper eyelids and lower eyelids.

Palpebral fissures: between the upper and lower eyelids are called palpebral fissures

Palpebral margin: the free edge (chordus) of the upper and lower eyelids. The front lip has neatly arranged eyelashes; the back lip has a row of pores, which are the openings of the meibomian glands.

Canthus: The connection between the upper and lower eyelids, divided into lateral canthus and medial canthus

eyelid skin

subcutaneous tissue

Muscle layer

Meibomian glands (meibomian glands)

palpebral conjunctiva

Transparent, thin mucosal tissue starting from the eyelid margin and ending at the limbus of the cornea

palpebral conjunctiva

bulbar conjunctiva

fornix conjunctiva

goblet cells

accessory lacrimal gland

Lacrimal gland: secretes tears and is located in the lacrimal fossa above the outer orbit of the eye.

Tear duct: a channel for removing tear fluid, including puncta, canaliculus, and common lacrimal duct

Lacrimal sac: located behind the medial canthal ligament and in the lacrimal sac fossa of the lacrimal bone

Nasolacrimal duct: connects the lacrimal sac above and opens into the inferior meatus downward.

Superior rectus muscle 8mm → oculomotor nerve innervation

Lateral rectus 7mm → abducens innervation

Inferior rectus muscle 6mm → oculomotor nerve innervation

Medial rectus muscle 5mm → oculomotor nerve innervation

Originates from the common tendinous ring at the orbital apex

Superior oblique muscle → arises from the common tendon ring at the orbital apex → innervates the trochlear nerve

Inferior oblique muscle → arises from the inner and lower part of the orbital wall → innervates the oculomotor nerve

artery

vein

Outer five layers + macular area - choroid

Inner five layers - central retinal artery

Avascular in the fovea

cranial nerve

Ciliary nerve root: lateral to optic nerve, retrobulbar anesthesia

sight path

optic nerve

Intraocular segment, intraorbital segment, intraosseous segment, intracranial segment

Square cone-shaped bone cavity: maxilla, zygomatic bone, frontal bone, sphenoid bone, ethmoid bone, lacrimal bone, palatine bone

Orbital depth: 4~5cm

Function: protect eyeballs

Optic foramen: located at the apex of the orbit through which the optic nerve passes

Superior orbital fissure: oculomotor, trochlear, abducens, 1st branch of trigeminal nerve (superior orbital fissure syndrome)

Infraorbital fissure: infraorbital artery, infraorbital nerve, 2nd branch of trigeminal nerve