Spatial Aspect of the Mouse Orbital Venous Sinus

The spatial aspect of the mouse orbital venous sinus and its topographical relation to the venous system of the head were studied in serial sections by light microscopy. The orbital venous sinus was found to extend between the orbital wall and the muscle cone and had a huge invaginated sac, which began from the antero-medial part of the sinus and enveloped most of Harder's gland. The orbital venous sinus received almost all the venous drainage from the eyeball, muscle cone, Harder's gland and conjunctiva, and communicated with the cavernous sinus, pterygoid plexus, superficial temporal vein and facial vein. The mouse orbital venous sinus may correspon d to the human superior and inferior ophthalmic veins. As well as draining blood from the orbital contents, it may play a significant role in producing exophthalmos when on the alert, in absorbing shock from the exterior to the orbital contents, and in promoting secretion from Harder's gland