The scleral venous sinus (canal of Schlemm) is a circular channel in theeye that collects aqueous humor from the anterior chamber and delivers it into the bloodstream via the anterior ciliary veins.
It is located in the inner part of the sclera close to the sclero-corneal junction junction. In a meridional section of this region this sinus presents the appearance of a cleft, the outer wall of which consists of the firm tissue of the sclera, while its inner wall is formed by a triangular mass of trabecular tissue; the apex of the mass is directed forward and is continuous with the posterior elastic lamina of the cornea. The sinus is lined by endothelium and communicates externally with the anterior ciliary veins.
The canal is essentially an endothelium-lined tube, resembling that of a lymphatic vessel. On the inside of the canal, nearest to the aqueous humor, it is covered by the trabecular meshwork, this region makes the greatest contribution to outflow resistance of the aqueous humor.