part of part of overlaps adjacent to camera-type eye orifice upper eyelid lower eyelid palpebral fissure MA:0001266 Wikipedia:Palpebral_fissure UBERON:0001819 SCTID:280576003 rima palpebrarum Orifice separating upper and lower eyelids. In the human adult this measures about 10mm vertically and 30 mm horizontally. It can be reduced in size in fetal alcohol syndrome. In Trisomy 9 the palpebral fissures can be upslanting. [WP,modified]. FMA:59110 inner canthus outer canthus