By Stephanie Colman

Detecting Canine Anal Sac Problems

The lowdown on problematic canine anal sacs.

Anal sacs are located on either side of your dog’s anus, between the external and internal sphincter muscles. Depending on the dog, they range in size from that of pea to a lima bean. Sebaceous glands within the lining secrete a foul-smelling liquid. Under normal circumstances, the sacs empty on their own during bowel movements via a pair of ducts. This natural, routine emptying serves as a means of olfactory communication and establishing territory. Each dog possesses his own unique scent, which is why ritualized dog-to-dog greetings include copious rear-end sniffing. When a dog presents his rear for information gathering, the muscle movements involved in raising the tail apply pressure to the sac, prompting the release of additional scent.