Croup And Tail

Croup And Tail

Croup And Tail  | Form follows function. When one delves into the nuance of one part of a dog’s body, it is amazing how complex what seems to be a simple anatomical part can be. It seems there are as many differing types of tails as there are breeds. Bobtail, bushy, curled, gay, docked, otter, plumed, ringed, screwed, snap, squirrel, teapot handle, wheel, rat, saber, sickle, terrier, flag, tapered, rocker, bent, clamped, kinked, crooked, half moon, knotted, twisted—and these were just through the standards of the first four Groups! Luckily for us the normal mechanics are basically the same for any breed, so that is what we will discuss today.

The Croup

The three fused sacral vertebrae (see Figure 1. A–Sacrum) and the first four-to-five tail vertebrae (see Figure 1. B–Coccygeal Vertebrae) form the muscular area just above and around the set-on of the tail, which is defined as the croup. This group forms a slightly curved area, which is easily found upon physical examination (see Figure 2. Sacrum Side View). The structure of the sacrum (the three fused vertebrae) works as one unit, as there is no movement possible between them. The sacrum forms the anchor for the hind limb assembly where the transverse processes (the wings) of the sacrum join to the pelvis via a cartilaginous joint on both sides (see Figure 3). This very firm joining allows the direct transfer of the drive generated by the hind limbs to the spine (vertebral column).

Croup And Tail
Figure 1. Pelvic Girdle. A–Sacrum, B–Coccygeal Vertebrae, C–Hip Socket (Acetabulum), D–Pin Bone (Ischial Tuberosity)
Croup And Tail
Figure 2. Sacrum Side View A–Sacral Wing, B–Crest, C–Intermediate Crest, D–First Tail (Caudal) Vertebra

Whereas the angulation of the croup depends upon the curve of the sacral and tail vertebrae, the angulation of the pelvis depends upon the angulation formed at the sacroiliac joints, where the sacrum articulates with the iliac of the pelvis.

The function of the croup is to determine the set-on of the tail. The sacrum (sacral vertebrae) and the first several coccygeal (tail) vertebrae form the croup (see Figure 4 A). The angulation of the croup determines the tail set. If the croup is flat (horizontal) or level, the tail set will be high. If the croup is gently rounded, it becomes a continuation of the backline and the tail usually continues on the level of the spine, carried horizontally to the ground. If the croup is angled downward, the tail set will be low. The steeper the downward angle, the lower the tail set will be on the dog. The angulation of the croup is entirely dependent upon the curvature of the individual sacral and tail vertebrae.

Whereas the angulation of the croup depends upon the curve of the sacral and tail vertebrae, the angulation of the pelvis depends upon the angulation formed at the sacroiliac joints, where the sacrum articulates with the iliac of the pelvis. The pelvic girdle is formed by three primary, symmetrical bone pairs. On each side are (1) the ilium, (2) the ischium, and (3) the pubis bones (see Figure 4). The pelvic bones are joined directly to the three fused sacrum vertebrae by the sacroiliac joint. The angle in which the pairs of bones are attached to the sacrum is called the pelvic girdle slope. This angle varies from dog to dog. It is very important to know that the angulation of the croup and the angulation of the pelvis are INDEPENDENT of each other. Most often, the angles of the croup and pelvis are similar—a dog with a flat croup most often tends to also have a flat pelvis. But it is also possible for a dog to have a flat croup with a high tail set, and yet have a steep pelvis. This actually occurs quite frequently in my breed, the Pembroke Welsh Corgi, with its flat croup and high tail set, and yet the pelvis is steep and therefore, in motion, the dog cannot follow through behind.

The Tail

The tail is formed by a line of coccygeal vertebrae, usually twenty in number, which gradually become smaller toward the end of the tail. The first vertebra of the tail is about as wide as it is long. From this vertebra, the body of each following vertebra gradually lengthens to about the middle of the tail, and then the following vertebrae shorten toward the end of the tail.

Croup And Tail
Figure 3. Sacroiliac Joint of Sacrum to Pelvis
Croup And Tail
Figure 4. Pelvic girdle showing pelvic slope and croup (darker area) from the side.

As to the function of the tail, one may often look to the tail to determine the mood of the dog; happy, aggressive, stressed, etc. Dogs communicate with body language and the tail is no exception. A tail held high and wagging back and forth usually means a happy dog. A low, wagging tail may mean the dog is insecure or worried. A tail held horizontally to the ground may depict interest in something, and a tucked tail may mean the dog is unsure of the situation, is frightened, or is indicating submission. A dog with a tail held upright and rigid may be feeling challenged or threatened.

Not only does the dog use his tail to demonstrate his feelings, the tail is also used to spread the dog’s personal scent wherever he has been. Each dog has his own unique scent excreted from the anal glands, which can be widely spread by the motion (wagging) of the tail. The tail may also be used as a counterbalance to the weight of their body when in motion. Many dogs learn to use the tail to do just that in tight turns or when crossing narrow areas when working in search and rescue or competing in agility. Many breeds seem to be using their tail as a rudder, especially when working in water retrieving—whether it be waterfowl or bumpers. When watching the sighthounds running down the lure, it is often a lovely sight to see a long tail streaming out behind the dog. However, having lived with a tailless breed for over 45 years, I have never seen a Corgi suffer from the lack of a tail when working livestock or zipping around an agility arena—or even when swimming. I believe that any dog, even if born with a tail, can learn to adjust without one.

The many muscles and nerves associated with the tail of the dog are also associated with the rectum, the anus, and the pelvic diaphragm, and they contribute to bowel control and movement. So, there you have it. The tail is the end of this tale!

If you have any comments or questions, or to schedule a seminar on structure and movement, contact me via

  • My involvement with the world of showing dogs began in 1969 with the purchase of my first show dog, a German Shepherd Dog. In the mid-seventies I began breeding and showing Pembroke Welsh Corgis under the Jimanie prefix and have finished a championship on a Pembroke Welsh Corgi on the average of one a year for the last 45+ years - almost all were breeder/owner handled to their titles. In 2010, I formed a loose partnership with two long-time friends, Denise Scott and Linda Stoddard, and we now breed and show under the Trifecta prefix. I am a breeder/owner/handler and still breed and show. Over the years I have owned and shown dogs mostly from the Herding and Sporting Groups plus a few toy breeds. I started out showing dogs from the Herding Group, but as a hunter, I always had a “bird dog” and thus also showed Brittanys, Pointers, Golden Retrievers and Irish Setters over the years. I have finished dogs in several other breeds from the Sporting and Toy groups. I started my judging career in 1988 with AKC approval to judge German Shepherds, Cardigan and Pembroke Welsh Corgis. I judge the Herding, Sporting and Toy groups and several of the Non-Sporting breeds, as well. I have been fortunate enough to have judged dogs all over the US and Canada and also in Finland, Norway, Sweden, Jamaica, New Zealand, Australia, Ireland, China, the Philippines, Mexico and the United Kingdom. In 2011, I was accorded the supreme honor of being asked to judge the Welsh Corgi League show in the UK and in previous years both the Cardigan and Pembroke Nationals in the US. I have also had the honor of having judged many National and Regional Specialties for breeds I did not breed, own or show from the sporting, herding and toy groups throughout the years, an assignment I always enjoy! Some of the highlights of my judging career have been judging at Westminster Kennel Club in 2006, doing the Herding Group at the Rose City Classic in Portland which was shown on Animal Planet and the national specialties for Clumber Spaniels, Field Spaniels, Australian Shepherds, Miniature American Shepherd, Bouviers (Canada) and the Top Twenty competition for the Golden Retriever Club of America as well as both of the Corgi national specialties in the US and Pembrokes in Canada and the Welsh Corgi League show mentioned above. I make my living as an artist, mostly through the design of counted cross-stitch and needlepoint but also through paintings and sculpture as well as jewelry. I have recently begun authoring and producing DVDs on the canine, mostly dealing with structure and movement. Last, but certainly not least, I’ve been married to Jim Hedgepath since 1972 and am the mother of two and the grandmother of four. Thank you for the honor of being invited to judge your dogs.

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