Not true about the anal canal is -

The anal canal is not completely lined by squamous epithelium. The part above pectinate line is lined by simple columnar epithelium, the part between pectinate and Hilton's white line is lined by non-keratinized stratified squamous epithelium, and the part below Hilton's line is lined by true skin (stratified keratinized squamous epithelium). The lower part of the anal canal is supplied by pudendal nerve and is supplied by the inferior rectal artery. The anal canal is a site of the portosystemic anastomosis.