Dog Expertise

By Paolo Tartaro and Francesco di Paola Nuzzo
- Source: Magazine All About Chihuahua n° 6

We came to the description, as announced in the fifth issue of AAC, of the two regions of the trunk: the loins and the croup, recalling that they have a fundamental importance in the transmission of the movement.
We will analyze, in terms of dog-science, the lumbar and sacral vertebrae, uneven and short bones, that are the anatomical bone basis of the two regions.

The lumbar vertebrae are seven and are classified as uneven and short
The length and width of the body of these bone segments gradually increases from first to last.
The spinous process of lumbar vertebrae shows greater strength than the other vertebrae, with an inclination opposite to that of the cranial spinous process of the dorsal tract This inclination is not random but due to reasons of static and dynamic. The transverse processes are inclined skull ventral.
After the description of these vertebrae, before embarking on the study of the lumbar region, we shift our attention to what the standard requires in relation to this particular part of the trunk that must be strong and muscular.
The characteristics required in this part of the trunk may lead us to marginal considerations for the breed in question, because the chihuahua is a non-work breed, work for which it would be necessary strength and endurance, as reported by the FCI standard # 218 / 10.21.2009 ( Utilization: Companion dog - Without working trial)
We require these characteristics of strength in this region because also the chihuahua makes movements on the spot, regressive and progressive, the latter are considered work (we will describe these in future issues of AAC).
Analysing accurately the lumbar region, we will discover the importance of these qualities required by the standard to full-fill this work.
The anatomical basis of the loins are the seven lumbar vertebrae and the lumbar muscles of the region.
The loins are sometimes inaccurately called "region of the kidney." In fact, the kidney is an organ and not a region. The kidneys, however, are located on the underside of this region, specifically in the abdominal cavity.
The lumbar region is considered a bridge between the croup and the back that joins the front with the rear, an excessive length, as for any bridge too long, has a negative effect on strength.

Obviously, therefore, that the loins, in Chihuahua, as in all other breeds, must be solid, that is short and flexible, but not oscillating in motion
The short loin offer greater resistance and strength to movement and. long loins do not favor the motor impulse to the front and, consequently, it can sometimes be observed in the hind uncoordinated movement with the rest of the trunk.
Absolute value of the renal region is a good width, because this shows that this portion of the muscles are well developed, not only in length but in width, so the transverse processes of the seven lumbar vertebrae are well developed and it is important, because on them the insertion of the muscles of the region. takes place.
The upper profile of the lumbar region in Chihuahua should be slightly bent to facilitate relaxation and contraction in motion, the loins are in harmony with the back and rump, with no interruptions
In zoo-technical checks often the term long kidney is used when the trunk is too long. Do not be superficial in assessing the underlying causes of the long loins (or long kidney).
One reason is the increased development in the longitudinal direction of the body of the individual vertebrae, while remaining seven in number, this evidently causes the elongation of the region
It may happen, what happens to the neck of the giraffe, seven cervical vertebrae are present, as in Chihuahua,, but the giraffe neck is much longer just because of the particular length of the vertebral bodies.
The kidney may appear (but not be) long when the chest is underdeveloped in depth.

As mentioned in the previous issue of AAC (.... The greater the distance between the ribs, the greater the depth of the chest, decisive for the length of the trunk ...) inter-costal spaces determine the length of the side.
We have to deny, through some scientific sources and through breeding experience, that a long loin, not necessarily helps birth giving, or a numerous birth.
Many standards, including that of Chihuahua, attest that it is justified a little more length in of the kidney for reproductive reasons in females. With the knowledge that the uterine horns during pregnancy are also to occupy the hypo-gastric region, in any-case a short kidney must be sought, regardless of sex.
An optimum loin can fill other defects of the trunk while you hardly will find strength points to compensate for the lack of an optimum loin

Sacral vertebrae & croup
The three sacral vertebrae are welded together forming a single bone called the Sacred (part of the trunk, which in ancient times it was offered to the gods). It articulates with the last lumbar vertebra cranially, laterally, with the coxal.
The croup is an uneven region situated between the lumbar region and the tail, its anatomical basis is the sacred bone and the two coxal, region of extreme importance, which significantly affects the mechanics of movement.
The coxal (already described in the previous fifth issue of AAC) are the same three bones called Ilium, ischium and pubic welded together, and with the sacred bone they form the pelvis.
The main factors that influence the movement of the croup are its inclination, width and length. The characteristics of the croup are so fundamental that it is comparable to a drive shaft as it is the region that transmits the propulsive impulse movement that emerges from the opening of all corners of the back, affecting all regions of the trunk up to the front and causing the displacement of the trunk forward and upward.


In zoo-technical testing of this specific region, as well as good length, width and angle, the muscle development of the croup is valued, which is crucial because the muscles of this region, in the the phases of gaits and movements are subjected to two motions of great importance: distension and retraction. A long muscle has greater contraction and elongation so more power (a subject already discussed in detail in the fourth issue of AAC).
The length of the croup is measured from the tip of the ilium to the ischium.
Sagittal development of the croup can be considered valuable not only in Chihuahua, but in all breeds, because the length of this region acts as a mechanical lever arm of the power resulted from the muscles, facilitating a correct transmission of the movement, pushing and raising the trunk. (Croup long means long muscles and so we will have greater contraction).
Moreover, as shown by the study of the animal science , the length and direction of the coxal are proportional to the length of the muscles, thus promoting greater extension and contraction.
A proper width of the croup expresses a proper development of the bone structure and muscular system of this region, otherwise a close croup denotes inadequate bone and muscle development.
The width of the croup is absolute value, and it is measured between the outer tips of the hips.
The proper development of the transverse diameter of this part of the body requires a wide pelvis, fundamental prerogative in females to facilitate birth giving. Its width should never be greater than its length.
The inclination is certainly the cornerstone for the locomotor system of the dog. In most cases, dogs that have strength, is horizontal, in chihuahuas the upper profile of the croup is nearly at the level of the loin and back.
The Chihuahua described in the standard has the croup wide and strong , nearly horizontal or slightly inclined.
These features (horizontal or slightly inclined) provide high insertion of the tail, and promote faster pace, which is as it appears in the chihuahua breed standard (... long distance, flexible, energetic and active ....)
In dog-science ranking the croup is considered horizontal when when the thigh it is between 15 ° to 25 °, and is considered angled when it is between 35 ° to 45 °.
Keep in mind that the slope of the croup affects all corners of the rear and therefore modifies the motion.
In this sixth issue is even more clear that all the individual regions and subregions are subjected to rules imposed by the anatomy, the static and dynamic, indispensable for reasons of functionality, shape and type.
Every single part of the body is connected to another and depends inextricably on the other. An incorrect region will determine the presence of at least one other incorrect region of the body to rebalance (almost never at all) the system as a whole.
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