The frequency and location of specific retinal breaks in a consecutive series of 169 phakic and 121 aphakic primary nontraumatic rhegmatogenous retinal separations categorized into lattice and nonlattice groups was determined. Small horseshoe tears in the oral region of the retina at the posterior vitreous base were responsible for 44.1% of aphakic nonlattice detechments. Aphakic detachments associated with lattice degeneration had a greater relative frequency of associated nonlattice tractional breaks in addition to lattice breaks.