Neurovasculature of the orbit
After completing this study unit you will be able to:
- Identify the arteries and branches which supply structures of the orbit.
- Name the veins and tributaries that drain the orbital region.
- Describe the nerve supply of the orbit.
The orbits are bony cavities of the viscerocranium which house the extraocular muscles, lacrimal apparatus eyeball and adipose tissue.
The ophthalmic artery provides the main arterial supply to the orbit with minor contributions from the external carotid artery. Originating as a branch from the internal carotid artery, the ophthalmic artery travels through the optic canal to enter the orbit. Within the orbit, it gives off numerous branches which supply surrounding structures.
Similar to its arterial supply, the principal drainage system of the orbit is by the ophthalmic veins. The superior and inferior ophthalmic veins receive blood from the roof and floor of the orbit and drain into the cavernous sinus of the cranial cavity or pterygoid plexus of veins of the infratemporal fossa.
Facilitating vision, movements of the eye, tear production and general sensation are the nerves of the orbit which include the optic nerve (CN II), oculomotor nerve (CN III), trochlear nerve (CN IV), abducens nerve (CN VI) and autonomic nerves. The ophthalmic (V1) and maxillary branches (V2) of the trigeminal nerve (CN V) also supply branches which innervate structures of the orbit.
Find out more about the many neurovasculature structures of the orbit by watching the videos below!
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Take a closer look at the neurovasculature of the orbit in the galleries below.
Arteries and veins of the orbit
Nerves of the orbit
Long and short posterior ciliary arteries
Muscular branches of ophthalmic artery (anterior ciliary arteries)
Central retinal artery
Anterior and posterior ethmoidal arteries
Medial palpebral arteries
Dorsal nasal artery
Superior ophthalmic vein
Tributaries: nasofrontal vein, anterior and posterior ethmoidal veins, lacrimal vein, vorticose veins, ciliary veins, central retinal vein, episcleral veins
Drains into: cavernous sinus
Inferior ophthalmic vein
Drains into: superior ophthalmic vein/ cavernous sinus/ pterygoid plexus of veins
Central retinal vein
Drains into: cavernous sinus but may join the superior ophthalmic vein
Drains into: ophthalmic veins
Drains into: pterygoid plexus of veins
|Cranial nerves||Optic nerve (CN II)
Oculomotor nerve (CN III)
Trochlear nerve (CN IV)
Ophthalmic branch of trigeminal nerve (V1)
Maxillary branch of trigeminal nerve (V2)
Abducens nerve (CN VI)
|Oculomotor nerve (CN III)||
Superior branch of oculomotor nerve
Inferior branch of oculomotor nerve
Branch of oculomotor nerve to ciliary ganglion
|Ophthalmic nerve (V1)||
Posterior ethmoidal nerve
Anterior ethmoidal nerve
Long ciliary nerves
Branch of nasociliary nerve to ciliary ganglion
|Maxillary nerve (V2)||
Zygomaticotemporal nerve (Communicating branch of zygomaticotemporal nerve to lacrimal nerve)
Peripheral parasympathetic ganglion which relays parasympathetic impulses from the oculomotor nerve to target structures. The ciliary ganglion also transports sympathetic impulses from the internal carotid plexus and sensory impulses from the nasociliary nerve.
Short ciliary nerves
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