Lining of the anal canal immediately inferior to the pectinate line and extending for about 1.5 cm to the anal verge; it is devoid of hair and sebaceous and sweat glands, and so is not true skin, although it is squamous epithelium; it is pale, smooth, thin, and delicate, and shiny when stretched; it is especially vulnerable to abrasion (as from coarse toilet paper) and chemical irritants (soaps), and is amply provided with tactile and nociceptive (i.e., pain, itch) endings innervated by the inferior rectal (pudendal) nerve.
