Orbit

Orbit is the skull's compartment containing the eyeball, extraocular muscles, lacrimal gland, ophthalmic blood vessels, and multiple cranial nerves. The medial and inferior wall of the orbit is particularly thin and fragile* that may play an essential role in the compensatory "emergency" decompression of the orbit in case of direct eye trauma.

  • * Brady S, et al. The diagnosis and management of orbital blowout fractures: update 2001. Am J Emerg Med, 2001;19(2):147-154.
    •
    Icon of crossfade image Aditus orbitalis, or the opening to the orbit
    Opening of orbit
    Anterior opening to the right orbit. Frontal view.
    The list of terms: Aditus orbitalis – Orbital aditus (opening to the orbit)
    Margo supraorbitalis (aditus orbitalis) – Supraorbital margin (of orbital aditus)
    Margo medialis (aditus orbitalis) – Medial margin (of orbital aditus)
    Margo infraorbitalis (aditus) – Infraorbital margin (of aditus)
    Margo lateralis (aditus) – Lateral margin (of aditus)
    Paries superior orbitae – Upper wall of orbit
    Paries medialis orbitae — Medial wall of orbit
    Paries inferior orbitae — Inferior wall of orbit
    Paries lateralis orbitae — Lateral wall of orbit
    Fissura orbitalis superior — Superior orbital fissure
    Fissura orbitalis inferior — Inferior orbital fissure
    Icon of crossfade image Markup for lateral view of zygomatic bone
    Lateral surface of right zygomatic bone
    Medial wall of the orbit.
    In terms of the skeleton, the medial wall of the orbit is the most complex one. Note the orbital process of palatine bone that forms a fraction of the wall, but is a useful anatomical landmark for endoscopic endonasal surgical approach to the orbit's medial wall.*.
    The list of terms: Processus frontalis maxillae – Frontal process of maxilla
    Os lacrimale – Lacrimal bone
    Lamina orbitalis ossis ethmoidalis – Orbital plate of ethmoid bone
    Processus orbitalis ossis palatini – Orbital process of palatine bone
    Corpus ossis sphenoidalis – Body of sphenoid bone
    Foramen ethmoidale anterius – Anterior ethmoidal foramen
    Foramen ethmoidale posterius – Posterior ethmoidal foramen
    Canalis opticus – Optic canal
  • * Gras-Cabrerizo J, Martel-Martin M, et al. Surgical anatomy of the medial wall of the orbit in 14 human cadavers. J Neurol Surg B Skull Base, 2016; 77(6):439–444.
    •
    Icon of crossfade image Lateral wall of the orbit with the terminology comments
    Lateral wall of the orbit
    Lateral wall of the orbit.
    The list of terms: Facies orbitalis ossis zygomatici – Orbital surface of zygomatic bone
    Facies orbitalis alae majoris ossis sphenoidalis – Orbital surface of the greater wing of sphenoid bone
    Foramen zygomatico-orbitale – Zygomatico-orbital foramen
    Fissura orbitalis superior – Superior orbital fissure
    Fissura orbitalis inferior – Inferior orbital fissure
    Icon of crossfade image Upper wall of the orbit with the terminology comments
    Upper wall of the orbit
    Upper wall of the orbit.
    The list of terms: Facies orbitalis ossis frontalis – Orbital surface of the frontal bone
    Facies orbitalis alae minoris ossis sphenoidalis – Orbital surface of the lesser wing of sphenoid bone
    Fossa glandulae lacrimalis – Fossa for lacrimal gland
    Icon of crossfade image Markup for the lower wall of the orbit
    Lower wall of the orbit
    Lower wall of the orbit.
    The list of terms: Facies orbitalis ossis zygomatici – Orbital surface of zygomatic bone
    Facies orbitalis maxillae – Orbital surface of maxilla
    Hamulus lacrimalis – Lacrimal hamulus (hook)
    Canalis nasolacrimalis – Nasolacrimal canal
    Sulcus infraorbitalis – Infraorbital groove
    Canalis infraorbitalis – Infraorbital canal
    Fissura orbitalis inferior – Inferior orbital fissure
    First published: Feb/2020
    Last update: 18/Nov/2020