2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part I: Anatomy
Chapter 3: Cranial Nerves: Central and Peripheral Connections
The Cerebral Vascular System
Other Venous Sinuses
Other venous sinuses include the superior sagittal, transverse, straight, sigmoid, and petrosal sinuses. The various components of the venous system are depicted in Figure 3-26. Thrombosis in any portion of the venous sinuses can lead to increased venous pressure and may cause intracranial hypertension with secondary CN VI palsy and papilledema.
Figure 3-24 CNs III–VI exit the midbrain and enter the cavernous sinus.
(Reproduced with permission from Spalton D, Hitchings R, Hunter P. Atlas of Clinical Ophthalmology. 3rd ed. New York: Elsevier/Mosby; 2005:642.)
Figure 3-25 Intracavernous course of the ocular motor nerves. CNs III and IV run in the lateral wall of the cavernous sinus along with CN V1 and CN V2. CN VI runs in close approximation to the carotid artery within the cavernous sinus itself. As the nerves course toward the anterior aspect of the cavernous sinus and the superior orbital fissure, the ophthalmic division of CN V (CN V1) divides into 3 branches: the lacrimal, frontal, and nasociliary nerves. ACP = anterior clinoid process; ICA = internal carotid artery; Inf. Br. = inferior branch; Prox = proximal; Sup. Br. = superior branch.
(Illustrations by Craig A. Luce.)
A, Cerebral venous sinus system. B, Drainage of the cavernous sinus.
(Illustrations by Christine Gralapp.)
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.