Figure 4: Diagram of the Trabecular Meshwork (TM) in control and glaucoma. The arrows indicate the direction of the aqueous humor, form the anterior chamber toward Schlemm´s canal trough the different regions. Aqueous humor flows through the intercellular spaces and crosses the inner wall of the Schlemm´s canal via two different mechanisms, the intercellular route and the transcellular route. The resistance of aqueous humor flow increases progressively from the anterior chamber to Schlemm´s canal as intercellular spaces narrow. In addition, in glaucoma the spaces are reduced by the collapse of the cells due to the high pressure, and the secretion of fibrillar material to the extracellular space by the subendothelial cribriform and juxtacanalicular cells. VersionfromLlobet et al. News Physiol Sci (2003) 18: 205-209.