Elsevier

Survey of Ophthalmology

Volume 44, Issue 4, January–February 2000, Pages 303-323
Survey of Ophthalmology

Diagnostic and surgical techniques
Anatomy of the Orbital Apex and Cavernous Sinus on High-Resolution Magnetic Resonance Images

https://doi.org/10.1016/S0039-6257(99)00115-0Get rights and content

Abstract

Diseases of the orbital apex and cavernous sinus usually present with involvement of multiple cranial nerves, corresponding to the complex anatomy of the region. In nontraumatic disorders, magnetic resonance imaging is the diagnostic modality of choice. However, its capabilities can be fully used only with thorough knowledge of the complicated topographic relationships in this region. This article describes the imaging anatomy of the cranio-orbital junction and adjacent subarachnoid spaces. High-resolution magnetic resonance images of normal subjects are presented, and the results are compared with findings reported in the literature. The following anatomic structures can be visualized on high-resolution magnetic resonance images: extraocular muscles and corresponding connective tissue, major orbital and cerebral arteries, ophthalmic veins, cavernous sinus, and all sensory and motor cranial nerves of the eye along their intraorbital and intracranial course.

Section snippets

Examination Protocols

Magnetic resonance imaging examinations were performed in eight normal volunteers on a 1.5-T MRI unit (Gyroscan ACS-NT; Philips Medical Systems, Best, the Netherlands). A circular polarized head coil was used for the cavernous sinus and brain stem, and a surface coil with a diameter of 17 cm was used for the orbital apex. Scans 1.2 to 3 mm thick with −0.6- to 0.3-mm interslice gap were obtained in axial, oblique-axial (along the neuro-ophthalmic plane82, 83), coronal, oblique-coronal (along the

Bony anatomy

Cortical bone does not produce a perceptible signal and is seen only indirectly by contrast demarcation to adjacent signal-generating tissue (e.g., brain, cerebrospinal fluid [CSF], muscle, fat, sinus mucosa, etc.). Cancellous bone is visualized indirectly by its fatty tissue content.

The orbital apex is defined as the region between the posterior ethmoidal foramen and the openings of the optic canal and the superior orbital fissure. The posterior ethmoidal foramen is visible on axial and

Sequences and coils

Magnetic resonance imaging demonstrates the anatomy of the orbit and retro-orbital region with superb detail. The best resolution of orbital structures is presently obtained by using standard T1w SE2, 3 or T2w TSE pulse sequences. Conventional T2w and proton density images need too long an acquisition time leading to motion artifacts. For the orbits, local surface coils2, 3 and, whenever possible, phased assay coils should be used. However, since the signal decay in the orbital apex depends on

Anatomic Features Demonstrated by MRI

All major anatomic structures, including the origin of the extraocular muscles27 and the apical orbital connective tissue system, can be demonstrated by MRI.

In the selected pulse sequences, blood vessels usually appear dark (“signal void”), as discussed earlier.52 All important arterial and venous vessels of the orbit can be identified without contrast enhancement.26

It is also possible to delineate the intraorbital and intracranial course of sensory and motor cranial nerves of the orbit on MRI.

Clinical Implications

High-resolution MRI enables exact delineation of space occupying orbital processes in relation to surrounding anatomical structures, thus facilitating planning of surgical procedures. This feature will be essential for computer-assisted surgery using neuronavigation.59

MRI reveals information on blood flow and may differentiate between flowing and stagnant blood in orbital vascular lesions. This is extremely important for treatment planning. Magnetic resonance angiography may provide further

Method of Literature Search

An on-line search of the international literature was conducted by MEDLINE, covering all years from 1966 to 1999, and using the following search words: magnetic resonance imaging (MRI), cavernous sinus, orbital apex. Other sources included original and review articles from our own files, articles cited in the reference lists of other articles, and standard textbooks on orbital imaging and anatomy. An important inclusion criterion was the coverage of anatomic and radiologic rather than purely

Outline

I. Examination protocols

II. Imaging

A. Bony anatomy

B. Extraocular muscle and connective tissue

system anatomy

C. Cranial nerve anatomy

1. Optic nerve and chiasm

2. Motor nerves

a. Oculomotor nerve

b. Trochlear nerve

c. Abducens nerve

3. Sensory nerves

a. Ophthalmic nerve (V.1)

b. Maxillary nerve (V.2)

D. Vascular anatomy

1. Arterial system

a. Internal carotid artery

b. Ophthalmic artery

2. Venous system

a. Veins

b. Parasellar venous plexus (cavernous sinus)

III. Discussion of techniques

A. Sequences and coils

B.

Key to Abbreviations

ACA anterior cerebral artery

ACP anterior clinoid process

AICA anterior inferior cerebellar artery

BA basilar artery

C clivus

CC chiasmatic cistern

CLT cisterna laminae tecti

COI colliculus inferior laminae tecti

COS colliculus superior laminae tecti

CP cerebral peduncle

CRA central retinal artery

CSF cerebrospinal fluid

DS diaphragm sellae

ES ethmoidal sinus

FLB frontal lobe of brain

FN frontal nerve

FV fourth ventricle

G globe

GWS greater wing of sphenoid bone

H hypophysis

ICA internal carotid artery

IH

Acknowledgements

We thank our radiologic technicians for collecting the imaging data, Erika Just for her secretarial assistance, and Peter Mentil and Anton Jaeger for preparing the figures.

The authors have no proprietary or commercial interest in any products or concepts discussed in this article.

This study was supported by the Ludwig Boltzmann-Institute for Interventional Magnetic Resonance, St. Pölten, Austria.

References (84)

  • L.M. Hamed et al.

    Magnetic resonance angiography of vascular lesions causing neuro-ophthalmic deficits

    Surv Ophthalmol

    (1993)
  • M. Hashimoto et al.

    Vascular compression of the oculomotor nerve disclosed by thin-slice magnetic resonance imaging

    Am J Ophthalmol

    (1998)
  • H.L. Hudson et al.

    Graves exophthalmos unrelated to extraocular muscle enlargementsuperior rectus muscle inflammation may induce venous obstruction

    Ophthalmology

    (1991)
  • L.B. Kline

    The Tolosa-Hunt syndrome

    Surv Ophthalmol

    (1982)
  • L.B. Kline et al.

    Computed tomographic evaluation of the cavernous sinus

    Ophthalmology

    (1982)
  • L. Koornneef

    Orbital septaanatomy and function

    Ophthalmology

    (1979)
  • B.L. Lam et al.

    Subarachnoid fluid of the optic nerve in normal adults

    Ophthalmology

    (1997)
  • B. Langer et al.

    MRI of the normal orbit and optic pathway

    Radiol Clin North Am

    (1987)
  • M.F. Mafee et al.

    Optic nerve sheath meningiomasrole of MR imaging

    Radiol Clin North Am

    (1999)
  • I. Mombaerts et al.

    What is orbital pseudotumor?

    Surv Ophthalmol

    (1996)
  • K. Ohtsuka et al.

    Enhanced magnetic resonance imaging in a patient with acute paralysis of the inferior division of the oculomotor nerve

    Am J Ophthalmol

    (1997)
  • K. Ohtsuka et al.

    Vascular compressive abducens nerve palsy disclosed by magnetic resonance imaging

    Am J Ophthalmol

    (1996)
  • C.F. Parsa et al.

    Absence of the abducens nerve in Duane syndrome verified by magnetic resonance imaging

    Am J Ophthalmol

    (1998)
  • J.G. Sacks

    Peripheral innervation of extraocular muscles

    Am J Ophthalmol

    (1983)
  • B.F. Sanchez-Dalmau

    Young boy with progressive double vision

    Surv Ophthalmol

    (1998)
  • K.D. Steinsapir et al.

    Traumatic optic neuropathy

    Surv Ophthalmol

    (1994)
  • A.L. Weber et al.

    Pseudotumor of the orbit

    Radiol Clin North Am

    (1999)
  • F.W. Zonneveld et al.

    Normal direct multiplanar CT anatomy of the orbit with correlative anatomic cryosections

    Radiol Clin North Am

    (1987)
  • S.W. Atlas

    Magnetic resonance imaging of the orbitcurrent status

    Magn Reson Q

    (1989)
  • S.W. Atlas et al.

    Orbit

  • M.A. Bedford

    The “cavernous” sinus

    Br J Ophthalmol

    (1966)
  • M.P. Bergen
  • M.P. Bergen et al.

    The vascular system in the orbitspatial relationships

    Orbit

    (1983)
  • Bilaniuk LT: Magnetic resonance imaging: orbital anatomy, in Newton TH, Bilaniuk LT (eds): Radiology of the Eye and...
  • J.F. Bonneville et al.

    Dynamic CT scanning of the cavernous sinus

  • S.F. Byrne

    Standardized echography of the eye and orbit

    Neuroradiology

    (1986)
  • P. Caliot et al.

    The intraorbital arrangement of the anterior and posterior ethmoidal foramina

    Surg Radiol Anat

    (1995)
  • C.M. Citrin

    High resolution orbital computed tomography

    J Comput Assist Tomogr

    (1986)
  • D.L. Daniels et al.

    Skull base

  • D.L. Daniels et al.

    Orbital apexcorrelative anatomic and CT study

    Am J Roentgenol

    (1985)
  • D.L. Daniels et al.

    Magnetic resonance imaging of the cavernous sinus

    Am J Neuroradiol

    (1985)
  • P. De Potter et al.
  • Cited by (42)

    • Polymicrobial sphenoethmoid sinusitis with orbital apex extension presenting as vision loss

      2020, Otolaryngology Case Reports
      Citation Excerpt :

      Our patient represents the rare case of sphenoethmoid sinusitis with extension into the orbital apex which presented as isolated vision loss. The orbital apex is defined as the region between the posterior ethmoidal foramen and the openings of the optic canal and the superior orbital fissure [3]. This area functions as the craniofacial junction and serves as a conduit for a variety of neural and vascular structures both to and from the orbit.

    • High-Resolution Isotropic Three-Dimensional MR Imaging of the Extraforaminal Segments of the Cranial Nerves

      2018, Magnetic Resonance Imaging Clinics of North America
      Citation Excerpt :

      CN IV.g exits the skull in the superolateral portion of the superior orbital fissure, external to the annulus of Zinn, along with the frontal and lacrimal branches of the ophthalmic division of CN V.1. g,12 eventually innervating the superior oblique muscle. CN VI.f travels through the central portion of the superior orbital fissure along with the CN III.f to enter into the orbit and innervates the lateral rectus muscle.12

    • Quantitative computed tomographic predictors of compressive optic neuropathy in patients with thyroid orbitopathy: A volumetric analysis

      2012, Ophthalmology
      Citation Excerpt :

      Similar to our findings with our recti volumetric analysis, multivariate modeling of recti muscle diameters found only the medial rectus diameter to be independently associated with DON. The orbital apex constitutes the region between the posterior ethmoidal foramen, optic canal, and superior orbital fissure.11 The greater effect of the medial rectus on the development of optic neuropathy may best be explained by the closer proximity at the orbital apex (Fig 8) of the medial rectus muscle to the optic nerve as it enters the optic canal (Fig 9, available at http://aaojournal.org).

    • Clinical anatomy of the superior orbital fissure and the orbital apex

      2008, Journal of Cranio-Maxillofacial Surgery
      Citation Excerpt :

      The superior branch of the oculomotor nerve is the structure closest to the medial rim of the fissure; the trochlear nerve is the closest to the superior rim and the abducens nerve is the closest to the inferior rim (Govsa et al., 1999). Others state that three separate compartments within the fissure can be distinguished: lateral, medial and inferior (Natori and Rhoton, 1994, 1995; Ettl et al., 1997, 2000). The lateral component is consistent with the narrow part of the superolateral fissure and contains the trochlear nerve, the frontal nerve, the lacrimal nerve and the superior ophthalmic vein.

    View all citing articles on Scopus
    View full text