Orbit and optic nerve

Author: Nat Pernick, M.D. (see Authors page)

Revised: 11 May 2018, last major update February 2014

Copyright: (c) 2004-2018, PathologyOutlines.com, Inc.

PubMed Search: Orbit [title] optic nerve

Cite this page: Pernick, N. Orbit and optic nerve: general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/eyeorbitgeneral.html. Accessed December 17th, 2018.
Definition / general
  • Orbit contains globe and its fibrous covering (Tenon capsule), lacrimal gland, optic nerve and its meningeal covering, extraocular muscles, cartilaginous trochlea, blood vessels and delicate fibroadipose connective tissue
  • Floor of orbit is roof of maxillary sinus
  • Medial wall of orbit (lamina papyracea) separates orbit from ethmoidal sinuses
  • Proptosis: forward displacement of eyeball (or other organs), due to any disease that increases orbital contents, since orbit is closed medially, laterally and posteriorly
  • Exophthalmos: abnormal protrusion of eyeball
    • Common symptom of orbital disease, although often due to thyroid disease and not biopsied
    • Other common causes of exophthalmos are mucocele from paranasal sinus, hemangioma, inflammatory pseudotumor
  • Optic nerve:
    • Surrounded by meninges; part of central nervous system
    • Not usually biopsied
    • Often has psammoma bodies or drusen (calcified acellular globular concretions of nerve fibers)
    • Site of convergence of one million axons from retinal nerve fiber layer
    • Nerve head accounts for physiologic blind spot in normal visual field
    • Receives blood supply from branches of ophthalmic artery
    • Surrounded on both sides by short posterior ciliary arteries
  • Lamina cribrosa:
    • Site of myelination of optic nerve axons
    • Highlighted with Luxol fast blue or other myelin stains
  • Trochlea:
    • Arc shaped structure through which tendon of superior oblique muscle passes before insertion upon eyeball
    • The only cartilaginous structure in normal orbit
  • Tumors should be reported using formats published for their counterparts elsewhere in body
  • Drainage through submandibular, parotid and cervical lymph nodes through vascular anastomosis
Radiology images

Images hosted on PathOut server:

Normal eye and orbital contents
Missing Image

MR #1 (T1 weighted)

Missing Image

MR #2 (T2 weighted)

Missing Image

MR #3 (T1 weighted) shows coronal section
of orbital contents posterior to globe


Images hosted on other servers:
Missing Image

Optic nerve

Missing Image


Missing Image

Extraocular muscles in orbit

Microscopic (histologic) images

Images hosted on PathOut server:
Missing Image

Intraocular and orbital portions of optic nerve

Missing Image

Cross section of optic nerve parenchyma and meninges

Images hosted on other servers:
Missing Image Missing Image Missing Image

Optic nerve and fovea centralis