Strays Anatomy

WHAT ARE THEY?
Anal sacs are small paired pockets located between the internal and external anal sphincter muscles, one on each side of the anus at the 4 and 8 o’clock position.  The sac empties through a short and narrow duct to the surface near the inside edge of the anus.  Each sac is lined with abundant sebaceous (oil) glands and numerous apocrine (sweat) glands.  The secreted substance is a semi-oily, brownish fluid that packs an odor strong enough to gag a maggot!  For unknown reasons some dogs’ anal sacs produce a rather thick, semi-solid material which is much more prone to impacting the sac due to the sac’s inability to pass this semi-solid material through the narrow duct to the outside.  In many of these cases the sac will become infected, cause pain and inflammation and even break through to the skin surface.  The abscessed anal sac may need surgery to provide drainage and curettage of the damaged and infected sac and surrounding tissue.  Antibiotics are indicated in abscessed anal sac disease.

WHAT THEY DO?
One study indicated that anal sac disorders affects about 12% of dogs. There are a number of theories why dogs, cats, skunks, and other mammals have anal sacs and what possible use they may have.  One theory states that anal sac contents, when excreted with the passing stool or by anal sphincter muscle contraction, act as a powerful territorial scent marker somewhat akin to humans posting a No Trespassing sign.  Another theory states that the anal sac material lubricates hard stool, which makes passage easier.  Humans do not have anal sacs.  It’s bad enough that some humans get hemorrhoids, which are dilated, irritated blood vessels at the anus; luckily, dogs do not get hemorrhoids.

CAUSES OF ANAL SAC PROBLEMS
There are no predictable antecedents to painful anal sac disorders.  Infections, obstruction and subsequent overfilling (called impaction), and rupture with drainage through the perianal skin are the most common Anal sac surgery to remove anal sacs from a dogclinical presentations.  Anal sphincter muscle dysfunction, enlarged anal sacs that are not compressed properly by the anal sphincter muscle, hypersecretion from the anal sac lining, obstructed or constricted anal sac ducts all may be predisposing circumstances for anal sac problems.

IMPACTED ANAL SACS
Some dogs may be born with very narrow channels that lead from the sacs to the edge of the anus, therebyPet Foods and Supplies! obstruction the flow of anal sac material.  Acquired damage to the duct can occur when perianal infections, trauma, allergies and inflammation compress or obstruct the narrow channel leading from the sac to the surface.  For unknown reasons some dogs produce a thick or dry material from the sac lining which makes passage of the material through the narrow ducts impossible.

AGE/BREED CONSIDERATIONS
There is no age or sex predisposition to anal sac pathology.  Uncommon in large breeds, infections and impactions are often experienced by small breeds such as Toy and Miniature Poodles, Chihuahuas, and Lhasa Apsos.  Cocker Spaniels, Basset Hounds, and Beagles rank high on the list of breeds affected by anal sac difficulties.

DIET
Some groomers and animal health care workers believe feeding a diet rich in fiber aids in emptying the sacs. The pressure of the firm stool against the colon wall near the anus may help to express the anal sac contents.  Dogs that have an existing problem such as infection or obstructed ducts, though, probably won’t respond to dietary changes; modifying the diet with more or less fiber yields inconsistent benefits.

HOW TO RECOGNIZE A PROBLEM
There is an 88 percent chance the thought of anal sacs will never even occur to you.  However, if your dog is one of the 12 percent that scoots his rear bumper along the carpet, frequently turns to lick or bite at the base of his tail or anal region, or displays discomfort when passing stool, it would be advisable to make an appointment with the veterinarian.  If left untreated, anal sac impactions, infections and abscesses can be a reoccurring nuisance for your dog so be proactive about an evaluation if your dog displays any discomfort in the tail or anal region.

THE ULTIMATE SOLUTION
“Do-it-yourself-anal-sac-expressing” can be done at home once your veterinarian has instructed you.  (Yuck… be careful about contact with anal sac secretions or you’ll be very unpopular with yourself and others!)  Some cases respond to infusion of the sacs with antibiotics in addition to oral medication.  In chronic cases, careful surgical removal of the anal sacs can be curative; the dog never has another annoying bout of anal sac disease.  Be sure to discuss the pros and cons of surgery if chronic problems lead you in that direction.