Dog Anal Gland PictureThis illustration shows the relative size and position of the anal glands in dogs (often referred to as anal sacs). Note that the anal glands are internal and cannot be seen when viewing the rear end of a dog. When the anal glands become blocked or swollen they can enlarge which creates discomfort for your pet. Your pet may try to relieve this pressure by scooting or licking the area. This illustration shows only one enlarged anal gland but in most cases both anal glands are affected.