Azzam Daniel, Cypen Sanja, Tao Jeremiah
Gavin Herbert Eye Institute, University of California, Irvine, School of Medicine, Irvine, CA
Gavin Herbert Eye Institute, University of California - Irvine
The orbital cavity drains via a system of venous blood vessels referred to collectively as the ophthalmic veins. The primary ophthalmic veins are the superior ophthalmic vein (SOV) and inferior ophthalmic vein (IOV). Accessory veins include the medial ophthalmic vein and middle ophthalmic vein, which occur in approximately 40% and 1% to 20% of the population, respectively. The ophthalmic veins anastomose with the facial venous system and drain into the cavernous sinus and intracranial veins (Figure 1). Of the ophthalmic veins, the SOV is the largest caliber with the greatest diameter. It originates in the anterior medial orbit from the junction of the supraorbital, supratrochlear, and angular (a branch of the facial vein) veins medial to the superior rectus muscle insertion and posterior to the trochlea. The SOV then travels posteriorly in a diagonal manner (from medial to lateral) coursing inferior to the superior rectus muscle and superior to the optic nerve and ciliary nerves. Once it reaches the lateral edge of the superior rectus muscle posteriorly, the SOV traverses the superior orbital fissure outside of the annulus of Zinn and drains into the cavernous sinus. The IOV originates as a venous plexus between the globe and the inferior rectus muscle near the anteromedial portion of the orbital floor. The IOV often splits into two branches: one exits the orbit via the inferior orbital fissure to drain into the pterygoid venous plexus while the other exits via the superior orbital fissure to empty into either the SOV or the cavernous sinus directly. The cavernous sinus, a component of the dural venous sinus pathway, drains via the superior and inferior petrosal sinuses and the sigmoid sinus into the internal jugular vein.
眼眶通过一组统称为眼静脉的血管系统引流。主要的眼静脉是眼上静脉（SOV）和眼下静脉（IOV）。附属静脉包括眼内侧静脉和眼中间静脉，分别出现在约40%和1%至20%的人群中。眼静脉与面静脉系统吻合，并引流至海绵窦和颅内静脉（图1）。在眼静脉中，眼上静脉管径最大、直径最宽。它起源于眶内侧前部，由眶上静脉、滑车上静脉和角静脉（面静脉的一个分支）在直肌上缘内侧、滑车后方汇合而成。然后，眼上静脉以对角线方式（从内侧到外侧）向后走行，位于直肌下方、视神经和睫状神经上方。到达直肌后外侧缘时，眼上静脉穿过Zinn环外的眶上裂，引流至海绵窦。眼下静脉起源于眶底前内侧部分眼球与下直肌之间的静脉丛。眼下静脉常分为两支：一支经眶下裂出眶，引流至翼静脉丛；另一支经眶上裂出眶，直接汇入眼上静脉或海绵窦。海绵窦是硬脑膜静脉窦通路的一个组成部分，通过岩上窦、岩下窦和乙状窦引流至颈内静脉。
