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Serratus
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David Genadek
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 Posted: Thu Jul 20th, 2017 03:34 pm
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I have heard from two very credible sources the Serratus is responsible for lifting the base of the neck and opening the shoulders. This seems wrong to me. Firstly the serratus only has the ability to lift the rib cage when a foot is planted. It would seem to me by using the serratus in that manner you would be creating a tension in the front end that would be contrary to the concept of lightness. It seems to me that the base of he neck is lifted and the shoulders are opened by the Longus Coli and scalenus muscle activating the passive dorsal ligament system. What am I missing here?

DrDeb
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 Posted: Thu Jul 20th, 2017 07:05 pm
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David, this is a great question which -- in some form or other, usually less well stated than in your post -- gets asked at nearly every class or seminar I give. There is a great deal of confusion in the horse community about what "lifting the shoulders" or "lifting the withers" means and how it is accomplished.

First let's be clear that what you mean is the lifting of the front end of the ribcage BETWEEN the shoulders, not the lifting of one shoulder or the other, or both shoulders at once. The shoulder-blades in the horse lie slap up against the sides of the front end of the ribcage, so movement of the shoulders is always relative to the ribcage, and vice-versa, movement of the ribcage is always relative to the shoulders. What you are talking about is vertical movement of the ribcage between the shoulders.

The "top" of the ribcage in front is formed by the top surface of the withers, which is to say the row of top surfaces of the several dorsal spines which pertain to the second through about the 8th thoracic vertebrae. The highest part would be third, fourth, fifth. So when a rider perceives that the fore part of the ribcage is lifted between the shoulders, they are saying that the top of the withers rises relative to the top of the shoulder-blades.

The longus colli muscle, which raises the base of the neck, can indeed perform this action. To accomplish it, many of the neighboring muscles must be in a relaxed state; in other words, to accomplish lifting of the withers relative to the shoulder-blades requires co-ordination of function between many muscles -- the longus colli has to be contracting, but at the same time, for example, the rhomboidei (of the neck and of the anterior thorax) have to be shut off. If they are not shut off, they will block the longus colli's ability to raise the base of the neck.

We need to carefully picture "the base" of the neck. What is meant by this term is the declivity, or downward curve, which is naturally built into the vertebrae beginning all the way back at the anticlinal thoracic vertebrae, i.e. at about T16 to T18. The CORE of the vertebral chain, that is, the row of abutting vertebral centra, has a gentle upward arc from T3 through T18 and continuing backward through the lumbars and sacrum all the way to the base of the tail. The shape so formed is like that of a simple archer's bow, the kind you used as a kid at camp. However, the bow-shape in the horse is not lying in there level in most cases, and particularly not in our racing breeds such as the Quarter Horse or the modern American Thoroughbred; instead, it tilts downward toward the front.

This downward-tilted arc is strictly to be distinguished from the shape and orientation of the topline, the skin and fur that someone can stroke along the living horse's back; that contour is not dictated by the row of vertebral centra, but rather by the varying height of the dorsal processes which project upward from the centra. The dorsal processes are like pickets in a picket fence, and the skin contour of the topline is made just as if someone had come along with a chainsaw and trimmed off the tops of the row of pickets so that instead of their tops forming a level line, what you have instead is a gentle undulation which goes DOWN from the top of the withers to a low point more or less in the center of the horse's back. Hence, the topline supported by its "pickets" and the CORE which is formed by the series of abutting, spool-like vertebral centra, make opposite shapes.

What is being discussed here is the CORE only. To reiterate, it arcs but tilts downhill from back to front. When it arrives at T3, the shape of the chain flattens out briefly through T3 and T2, and at T1 it begins to tilt upward. This continues through cervical 7, 6, 5, when again it flattens somewhat at C4, begins to "turn over" at C3 which is continued through C2 and (slightly) C1 and finally the poll joint, the junction between the anterior end of the neck and the skull. 

"To raise the base of the neck" thus means two things: (1) to flatten out the declivity formed between T3 and C5 by pushing the bottom of the declivity up and thereby causing the head to move forward and downward. This is the "neck telescoping gesture" I discuss at length in "Principles of Conformation Analysis."

"To raise the base of the neck" also means (2) to raise the declivity itself, that is the zone between T3 and C5 relative to the shoulders.

Action (1) is primarily accomplished by the longus colli muscle. Action (2) is accomplished by the longus colli plus the cantilevering of the entire thoracic, lumbar, and sacral chain, which is caused by coiling of the loins, i.e. flexion of the rear part of the spinal chain, especially at the lumbo-sacral joint and the last two inter-lumbar joints, which are the "seat", that is the key locus of origin, of collection. When the loins coil, this tensions the (passive) dorsal ligament system, which attaches in front to the upper surfaces of the vertebrae which form the declivity to the base of the neck; and this tensioning acts to lift them upwards from the top. Thus, the action of collection, i.e. originating with the coiling of the loins and culminating in the raising of the base of the neck, is the product of muscular contraction (active) from below, i.e. longus colli and (in back) rectus abdominis and iliopsoas complex PLUS ligamentous and muscular tension (passive pulls) from above.

Now let us examine the serratus, its attachments and what actions it creates both passively and actively. It is important to remember that all muscles, when they are not actively contracting, are functionally ligaments. And wonderful ligaments they are, too, because when they are not contracting, muscles are quite stretchy. Thus, any muscle caught in a moment when it doesn't happen to be contracting can work, in that moment, like a bungee cord. Hence my statement immediately above "....ligamentous AND MUSCULAR tension (passive pulls) from above." The student must be careful of the difference in technical and common usage of the word "tension" in this statement: it is not being used in the common sense of "uptight". To tension a muscle, in the technical sense, no. 1 implies that the muscle is non-contracting, and no. 2 that it is being stretched by the actions of something other than itself, i.e. something that can pull on its ends so as to stretch it. To "tension" a muscle in the technical sense means to stretch that muscle. The whole of the longissimus dorsi, which is the largest and longest muscle in the horse's body, spends 60% of its time being a humongous bungee cord which lies along, and is the major former, of the horse's topline. If the importance of it being allowed to be a passive bungee cord were understood by most trainers, we would see 100% fewer sore backs (both human and equine!).

I would go so far as to say that the MAJOR function of the longissimus dorsi is to act as a bungee cord; its minor function is to make little, tweaky contractions timed to offset the tendency of the pelvis to twist from side to side. Likewise, the MAJOR function of the serrati is to be the upper component of the passively-elastic "thoracic sling". (The lower component is the pectoral muscle complex).

The serrati attach, above, to the inner surface of the upper part of the bony scapula. The attachment for the cervical division is a patch toward the front of the scapula, while that for the thoracic division is a patch toward the back of the scapula. The fibers of the cervical division are arranged as bundles; the bundles arc downward and forward to attach to the lower cervical vertebrae. The fibers of the thoracic division are also bundled, and they run downwards and rearwards to attach to the successive ribs back to somewhere between T11 and T14, depending upon the individual horse.

Given these attachments, and the fact that the anterior part of the thorax hangs down between the shoulder blades and the forelimbs that support them, if the serrati contract bilaterally, they will certainly raise the thorax between the forelimbs.

However, this is exactly what we do not want to have happen, just as having the horse bilaterally contract the longissimus dorsi is something we absolutely never want to see happen in a ridden or driven horse. It is people who have little experience with anatomy, who have never seen a demonstration on a fresh carcass, and who thus have a lot of trouble picturing the biomechanics in action, who make these mistakes. They are akin to the time Hilda Gurney -- who has no qualifications that I know of in biomechanics or anatomy study -- was invited to give a speech on these subjects to the California Dressage Society. She stood up there and told 'em that development, or even hypertrophy, of the trapezius muscle of the neck was a desirable sequel to "correct" dressage training. What caused her to say this was that she had in fact taken a few minutes to open and study a horse anatomy book. There is a fullness that develops in a correctly dressed horse in the region of the trapezius, but which in fact comes from muscular development as well as postural changes that originate much deeper within; whereas hypertrophy of the trapezius, if actually present, comes from quite other and very undesirable practices.

Another example is the widespread idea, also promulgated by the ignoramuses of dressage, is that the rider ought to be trying to "develop the horse's back", meaning get the longissimus dorsi to contract more often, more strongly, and bilaterally. This is completely in error and fatally so, for anyone who wants their horse to eventually actually be able to do flying changes or piaffe. Those who have understood this post to this point will readily see why: those who are naive about how the body works think that ALL muscular action, to be muscular action, must be active action; they do not understand that certainly 60%, and more probably something like 90%, of a muscle's work is done in the non-contracting state when it is being stretched ("tensioned") by something else.

So we come to the serrati, which can only perform their MAJOR function -- which is to act as the elastic sling in which the front end of the horse's thorax is supported -- when they are not contracting. Only when a muscle is not contracting does it have the capability of elastic, bungee-cord-like stretchiness. And it is this stretchiness, this elasticity, that gives the ride itself, the feel of the ride, its delightful lilt and bounce. So again, another naive but very common mistake -- made by educated veterinarians and laymen alike -- is that the source of the hard, pounding ride-feel that some horses give is faulty conformation, i.e. either an upright shoulder or else upright pasterns. To begin with, there is no such thing as a fully vertical shoulder or pastern angle in any normal horse that is sound enough to ride. And second, these structures, especially not the pasterns, are not the source of elasticity. The suspensory ligament complex which invests the ankle joints (and what is really being referred to as being at fault in the horse with "upright" pasterns), if it were dissected off the carcass and laid out flat on a grid and measured, has a total area of perhaps ten square inches. Total. The serrati, however, measure some three square feet of potential "elastic sheeting" per each side of the horse!

Thus it is the horse who CONTRACTS the serrati who gives the rough ride. David, you saw me several times do this demonstration in various classes -- where I lean up against a wall, supporting myself on the palms of my hands, and then bounce against the wall as if I were trotting, first with relaxed serrati (and thus my ribcage able to elastically move up and down between my forelimbs) and then with contracted serrati. When I bounce against the wall with serrati relaxed, there is little to no sound when my "hoofs" strike and it is visibly elastic and soft. When I tighten my serrati, the "hoof" strikes become loud and banging and it is visibly rough and hard.

You were the first to say this, right here in this Forum David, and I have often quoted it since: that is, that very few people recognize that the first thing we have to teach a horse, once he is OK enough with us to let us be up close to him and get on him and steer him around a little, is HOW  to use his body to carry the person's weight. Most horses have to guess because nobody shows them explicitly. Our school most certainly does show them explicitly but that is very rare worldwide. Because the horse usually has to "guess" how he is to function under saddle, just in terms of managing his rider's weight and the changes in balance that having a rider on top implies, he guesses wrong. And one of the commonest wrong guesses that horses make is that they have to clamp their serrati (and pectorals) all the time.

This, then, becomes one of the major jobs that every trainer in our school regularly faces: we have to take these horses that other people have already nearly ruined, and show them that no, you can actually take a step and NOT clamp the serrati, and NOT clamp your longissimus dorsi, and NOT clamp your pectorals, and NOT clamp your diaphragm.

So much for lifting the withers by means of the serrati: lifting the withers is desirable, and certainly, by looking in the anatomy book and thinking about how the serrati are attached, one could get the idea that having the withers lifted by means of the serrati is a desirable idea. But that's naive. Real riding requires understanding what collection is and where it comes from, to wit:

(1) Collection starts from, and is always primarily the product of, coiling of the loins.
(2) Milliseconds later, the coiling of the loins induces the horse to raise the center of the freespan of its back.
(3) The above two actions assist him in raising the base of the neck. Collection is completed by the raising of the base of the neck.

Cheers -- Dr. Deb


David Genadek
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 Posted: Thu Jul 20th, 2017 09:06 pm
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Sigh, Not missing a thing then. Thank you great reply.

Aloha
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 Posted: Thu Jul 20th, 2017 11:50 pm
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DrDeb wrote:

(1) Collection starts from, and is always primarily the product of, coiling of the loins.
(2) Milliseconds later, the coiling of the loins induces the horse to raise the center of the freespan of its back.
(3) The above two actions assist him in raising the base of the neck. Collection is completed by the raising of the base of the neck.

Wonderful reading (and thinking, and having to go look a few things up!)!
Dr. Deb, I hope it is OK to quote the last part of your post. I couldn't help but laugh when I realized that you have described what so many dressage people "talk" about when they refer to riding a horse "back to front". But ask them what they mean and it won't sound anything like what you wrote! Your description is very succinct and easy enough to understand. Not even any latin terms to look up! Should be posted on every arena wall!
Monica

DrDeb
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 Posted: Fri Jul 21st, 2017 02:16 am
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If they would all come and join in our upcoming full-body anatomy class, they would not only hear this description of collection (which I have been giving out in seminars and in print literally since the 1970's), but they would see and actually handle all the component parts in a way just as easy to understand but impossible to forget. Anybody who takes our anatomy class comes out of that class a better and more effective rider and trainer. Please spread the word -- we're signing up for the November class now. Cheers -- Dr. Deb

Sahara
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 Posted: Sun Jul 23rd, 2017 12:17 am
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DrDeb wrote:


"To raise the base of the neck" thus means two things: (1) to flatten out the declivity formed between T3 and C5 by pushing the bottom of the declivity up and thereby causing the head to move forward and downward. This is the "neck telescoping gesture" I discuss at length in "Principles of Conformation Analysis."

"To raise the base of the neck" also means (2) to raise the declivity itself, that is the zone between T3 and C5 relative to the shoulders.

Action (1) is primarily accomplished by the longus colli muscle. Action (2) is accomplished by the longus colli plus the cantilevering of the entire thoracic, lumbar, and sacral chain, which is caused by coiling of the loins, i.e. flexion of the rear part of the spinal chain, especially at the lumbo-sacral joint and the last two inter-lumbar joints, which are the "seat", that is the key locus of origin, of collection.
Cheers -- Dr. Deb




Is it correct to say a horse can perform action 1 telescoping the neck without engaging the loins even though this is not desirable?

I took this photograph recently of my daughter on her 18 year old mare. I believe she is telescoping her neck, however, I cannot tell to what extent, if any, her loins are involved.

Attachment: IMG_7054.PNG (Downloaded 92 times)

DrDeb
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 Posted: Sun Jul 23rd, 2017 03:15 am
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Sahara, I did not say that the horse not very strongly coiling its loins was undesirable; merely that the horse cannot be considered fully collected unless it also coils its loins. A horse can have "more in the neck" at times and still be OK, i.e. for example when at a walk, which ordinarily requires very little in the way of loin-coiling. All that is required is that it NOT hollow its back or extend its loins or brace up anywhere else.

Your photo is a beautiful illustration of a horse arching and telescoping its neck, which action is produced by the contraction of the longus colli muscle which underspans the declivity at the base; while at the same moment there is utter relaxation or "release" of all the muscles along the topline of the horse's neck. This is the proper coordination and it produces results that are certainly beautiful to look at.

I note the draping reins; the horse's head hangs vertical not because your daughter is pulling its nose in but instead because the base of the horse's neck is pushing its poll away from its withers and chest.

You both should be congratulated on correct understanding and practice. It's also great to see a horse (though he might be registered as a so-called "Paint") that has a good percentage of American Saddlebred in him, being given a chance to do ordinary work under saddle, to move in a normal manner, and to offer true collection. The feel these horses give is just wonderful, especially at the canter, so I hope your daughter has been enjoying all of that. Cheers -- Dr. Deb

Aloha
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 Posted: Wed Jul 26th, 2017 09:16 pm
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Yes, I try.

Unfortunately, people in my neck of the woods would rather drop a wad of money on a horse show than their education. They cry poor when told the cost of the class, but then spend even more $$ to go to a horse show to win $2 worth of ribbons. Their scores might go up and their vet bills go down if they improved their horses straightness and collection. And learned how that really happens. Now, if they made your class a requirement to win that first bronze medal, you'd have to franchise yourself! Unfortunately, again, the USDF is not really about education in my opinion, but rather collecting $$ from competition. I know there are those who would argue this. But the only requirements to win all those awards are the scores from test riding, not passing class tests.

The boards I used to post on "upgraded" their systems, so now I can't get on from this computer. I know you understand that frustration. Not buying a new 'puter just to post on a bulletin board. I will try to get the word out next time I'm at the library, where I can log on.

I did mention the class to a friend back east (waving at you in case you are reading this), and hope she might be able to make it this time. She might be able to twist my arm into joining her in that case.

I may be meeting up with the owner of the tack shop where we posted flyers for our classes, next weekend. With your permission, I could print out a few of our flyers with your new class dates with a link to this site for more information. I will remove all other location and contact info. I'm sure she would post them in the store. While I'm at it, wondering if she might be interested in purchasing and selling a few copies of your Workbook #1 in her store. I'm very familiar with her selection and think your book would be a wonderful addition. If I see her, I could let her look at my copy. Let me know what you think. Or feel free to send me an email.

Happy to pass on the word about this class. It's a wonderful opportunity to see what's really under the hood!


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