799 BUILDING A FUNCTIONAL DOG - The Crucial Role Of The Loins
BUILDING A FUNCTIONAL DOG - THE CRUCIAL ROLE OF THE LOINS
Over many years of dog-owning, the greatest joy for me has been to see my dogs galloping, really stretching their legs. I marvel at their remarkable physical coordination as well as savouring their spiritual release. Writer after writer will tell you of 'the powerhouse of the hindquarters' and the importance of the correct amount of bend in the stifle. Not so many will extol the extraordinary balance, synchronized control and anatomical harmony behind such athleticism. The powerhouse of the hindquarters cannot be harnessed if the flexibility of the spine and the transmission of power isn't there too. The link between the fore and hindquarters of the running dog captures the strength of the dog, but it's a link not always appreciated.
"To acquire the perfect silhouette the dog must obviously have sufficient length of loin to avoid the cramped, wheel-back stance which has periodically been quite common. This extra bit of loin is what makes the dog cover a lot of ground and was what Mrs McKay at the Laguna kennels always impressed on me made all the difference between an ordinary whippet and a top-class one." Those words from Bo Bengtson's book on the Whippet represent surprisingly rare coverage of this vital part of a dog's anatomy. Whole chapters have been written on heads and page after page on shoulders; a number of books are devoted to coat colour alone; but the loin is sadly neglected, usually only given a passing reference by sporting authors too. This is both an alarming omission and not a good omen for the breeding of soundly-constructed dogs.
But what is the loin? The Kennel Club definition describes it as the "Region of the body on either side of vertebral column between the last ribs and hindquarters". From that brief imprecise description, it is easy and forgiveable to understate the importance of this part of the canine anatomy. Nearly every breed standard dismisses the loin in a few words; it is rare to read even a mention of the loin in judges's critiques of their show entry. This might be understandable in say a Toy breed, but is a disappointing oversight in hound, terrier or gundog breeds. When I watch judges going over exhibits at shows I am amazed at how little attention is paid to this desperately important part of the canine anatomy.
It is not unusual for those involved in dogs to be fairly hazy about the loin. I can recall standing ringside at a hound-show, with a distinguished judge, and listening to his observations, especially those based on his confusing the hounds' flanks with their loins! A much-respected lurcher breeder once told me that for years he had thought that the groin was another word for the loin. I once sat through a two hour lecture on locomotion in the dog, given by a lecturer from a vet school, and realised that the loin had not been mentioned once. He did refer to muscles like the rectus abdominis, the principal flexor of the spine, the great oblique, which arches the back, flexes the spine or inclines it laterally, and the lumbo-dorsal/thoracolumbar fascia, where the loin is situated.
This distinguished scientist was so used to lecturing to students, undergraduates with a good knowledge of anatomy, that he had forgotten the importance of respectful simplification to an audience which lacked specialist knowledge but contained people just as intelligent, and certainly more perceptive, than he. What he lacked the empathy to explain was that the loins comprise the lumbar area, extending from the end of the rib cage to the start of the pelvis, forming the upper section of the couplings region. The coupling comprises the whole muscular band joining the chest and hindquarters, not just in the loin area. The loins overlie the lumbar vertebrae, can differ in length, flexibility and capability, according to the length of these bones and their substance, as well as to the width of their prominence on each side. This accounts for breed differences, originating in function.
No breed wants sagging loins, giving a drooping backline at the coupling. But requirements vary in breeds from slightly tucked loins, arched loins and a need to be 'light in loins'. The American Kennel Club standard for the American Staffordshire Terrier calls for 'loins slightly tucked'. This demands a waisted appearance from above or a dog 'slightly drawn in loins'. Our standard for the Dachshund expects a slightly arched loin which is short and strong, predictably in such a long-backed breed. The Basenji is expected to feature a short-coupled loin, with a definite waist, perhaps confusing the coupling with the loin. Most Staffordshire Bull Terriers that I see are light in loin, perhaps out of a desire to produce the appreciable waist in an otherwise muscular breed. The loin is not mentioned however in this Breed Standard.
The long dorsal muscle, which extends the spine or bends it to one side, is especially noticeable in the loins, where each vertebral bone carries the weight of the body in front of it, together with the weight of its own body mass. Towards the sacrum, each vertebra is accepting greater total weight than the one before it - the vertebrae enlarge, moving rearwards, throughout the lumbar region. It is not difficult to appreciate therefore the importance to the huge heavy dog, as well as the fast lithe leaping dog, of the loin. Breeders of Foxhounds have long been aware of this importance.
Capt Ronnie Wallace, perhaps the most respected hound breeder of the 20th century, has written on this subject: "It is very nice to see a back bone set in two cushions of muscle so that you could roll a billiard ball down it with no difficulty...you can have either a straight back, or the arched loins known as 'wheel backs'. Either of these may be acceptable, but you must have the right equipment at the back to go with them." He is stressing the mutual support needed between the loins and the hind-limbs. Richard Clapham, the Fell Hound expert, stressed this too, pointing out that the muscles of the loin are connected to those of the hind legs, so that any weakening of the former lessens the hound's ability to use his hind-leg muscles efficiently.
Fifty years ago, Clapham wrote: "The longer the body, the greater is the call upon certain muscles such as the broad dorsal muscle, which begins below the shoulder and spreads over the back and sides of the chest, until it tapers towards the loin. With increased length of loin, the hound is unable to get his hind legs well under his body, and the internal organs being spread over greater length, the strain in a downward direction is likewise increased. Thus, unless the muscles of the big hound are abnormally developed, he suffers from loss of power and endurance." The latter is a vital point; hound breeders acknowledged the impact made by sagging loins on endurance, but also knew the limitations of the hound being too short-coupled. Generally speaking, over-shortness of body, as opposed to shortness of back, carries more disadvantages than a little extra length, which gives more flexibility and easier whelping. A good Bull Terrier demonstrates this point well.
The flexibility needed when say a Greyhound is racing is quite astounding: the hind feet 'overtake' the fore feet, with the loin and the thigh both curved into just about a semi-circle when the hind-limb is stretched forward to its very limit. The elasticity which permits this is astonishing, but the soundness of construction and muscularity of the dog allows it. The loins have no support at all from any bones other than the seven lumbar vertebrae and act as the crucial link, the keystone 'bridge', between the front limbs, from the ribs forward, and the rear limbs - the legs, pelvis and tail. For structural strength, a slight arch here is essential, but too great an arch is a weakness. That is why the gift of 'an eye for a dog' puts one judge in a different class from another. A desirable arched loin can be confused with a roach or sway back.
Down the centuries, the words have been consistent: Berners - 'Backed lyke a beam'; Markham - 'A square and flat back, short and strong fillets'; Cox - 'Arched, broad, supple and showing enormous muscular development'; Stonehenge - 'The loins must therefore be broad, strong and deep, and the measure of their strength must be a circular one'. In his informative book on the Greyhound, H Edwards Clarke writes: "The very first test that any trainer makes of the condition of a greyhound is to run his hand over its back and loins...The first impression by touch should be one of supple firmness, of well-developed muscular tissue of a rubber-like consistency." Like Capt Wallace he sought a little trough or valley along the backbone. He looked for arching of muscle not any arching of the skeleton, a common fault in our show sighthounds, especially in Whippets and Borzois.
Clarke termed the roach or 'camel' back a skeletal malformation, a form of spinal curvature that 'militates against any possibility of smooth-flowing, free-striding movement'. At a championship show a few years ago, I saw a lady exhibitor proudly posing her winning Greyhound for the dog-press photographers despite its very obvious camel back! The somewhat brief breed standard for the Greyhound stresses an arched loin both in the General Appearance and the Body sections; perhaps a few more words on the need for a muscular arch rather than a skeletal arch would be a better guide. The standard of the Borzoi actually demands a back that is boney, free from any cavity and rising in a curve.
The Whippet is expected to feature a definite arch over its loin; the Borzoi however is supposed to possess the highest point of the curve in its back over the last rib, i.e. forward of the loin. Both are sighthounds built for speed. The American standard for the Borzoi calls for a back which is 'rising a little at the loins in a graceful curve'. That is more than a little different from ours and more likely to produce an efficient sighthound. There is a world of difference between a bent skeleton over the last rib and a curve of muscle over the loins, the latter benefiting the dog! The lumbar vertebrae are quite literally the backbones of the loins, lumbus being Latin for loin. Any arch should be over the lumbar vertebrae and not further forward.
In an attempt to appreciate the value of the loin to the dog, I think of the dog as a four-wheel drive rear-engined vehicle with its transmission in the loins. They are an absolutely key feature of the canine anatomy relating to movement. If we prize movement then we must understand the loins. But just try researching the subject even in weighty books on dogs. These may not be the best 2000 words, but may well be the first.