Dogs’ tails serve many important functions. They are important for balance. They are crucial for communication. And, for sillier dogs, they are playthings to chase.

Because tails are so expressive, you might be alarmed when your dog’s normally up-and-wagging tail goes limp. Could it be broken? And how would such an injury occur?

Trauma to the tail is, in my experience, the most common cause for a tail to dangle limply from its base. In these instances, strains and muscle injuries are more common than broken tails. For instance, many dogs use their tails to help them paddle when they swim. If a dog engages in an especially big day of watersports, he may wake up with a really sore tail the next day. This condition, which I affectionately call swimmer’s tail (a term that is not an official medical diagnosis), lasts a couple of days and usually resolves on its own with rest.

I also have seen dogs strain their tails after whipping them especially vigorously. Not long ago, I treated a dog who had been sprayed in the face by a skunk. It caused no real harm, but the poor dog did a super-fast 180 in response, and as he whipped his body around, he managed to strain his tail. After a skunk bath and a few days of rest, he was much better.

Although broken tails aren’t as common as the less serious injuries discussed above, they do occur. The tail consists of segments of bone connected to each other through a series of flexible joints, and “broken” tails can occur if one of the bones is fractured, or if one or more of the joints is dislocated. These sorts of injuries involve more serious trauma. A puppy may have its tail stepped on, a tail may be caught in a closing door or run over by a bicycle or rocking chair, the dog may be struck by a car or bitten by a larger animal, or — most perniciously — the dog may be the victim of a person who yanked hard on its tail.

Broken tails can be diagnosed through palpation and X-rays. The bad news is that treatment options are limited — it is not possible to place a cast on a tail. The good news is that most broken tails, especially dislocations that are not near the base (which are the most common type, in my experience), require no treatment other than painkillers while they heal. They usually heal without intervention, often leading to a kink in the tail that is permanent but not painful. For more serious fractures, especially near the base of the tail, surgical bone plating may rarely be available. Unfortunately, severely traumatized tails often require amputation.

The problems outlined above are not the only reasons for a tail to go limp. Bite wounds, lacerations, and infections can cause sudden loss of use. Problems with the anus or the anal glands also may contribute. Neurological disorders can affect the tail, and generalized body weakness may manifest through a limp tail.

Any dog that suddenly stops using its tail should see a vet. In most cases the problem won’t be serious, but without a physical exam it won’t be possible to know where a more troubling issue is developing.

Got a question only a vet can answer? Ask Dr. Barchas in the comments.