Heeft mijn paard hoofdpijn?

Over hoofdpijn bij paarden is nog weinig onderzocht en bekend.
Gezien de anatomie van het paard is het aannemelijk dat paarden, net als mensen, last  kunnen hebben van hoofdpijn.

Een van de mogelijke oorzaken van hoofdpijn is problematiek vanuit de hals.
Als eigenaar zijn we niet altijd goed genoeg in staat om pijn bij onze dieren te beoordelen. 
Hierdoor worden veel pijnklachten gemist.
Daarom moeten we extra scherp zijn op de signalen die ons paard geeft.
Signalen die een indicatie kunnen zijn van hoofdpijnklachten zijn;

• verandering van gedrag / chagrijnig doen
• reageren bij aandoen van halster of hoofdstel
• reageren bij aanraken van de hoge hals en oren
• schudden met het hoofd 
• reageren bij aanraking op het hoofd
• knarsetanden
• niet fijn in aanleuning / kantelen van het hoofd
  

Hoofdpijn kan verschillende oorzaken hebben.

Een van de oorzaken is overprikkeling van de uittredende zenuw van de tweede halswervel.

Overprikkeling van de Nervus Occipitalis Major leidt bij mensen tot ernstige (cluster) hoofdpijn. De klachten ontstaan als gevolg van prikkeling door irritatie van de nekgewrichten of (te hoge) spierspanning in de nek.
Het is zeer aannemelijk dat overprikkeling of irritatie van deze zenuw ook bij paarden tot (ernstige) hoofdpijn leidt. 

De tweede cervicale zenuw (C2) treedt links en rechts uit het laterale foramen van de tweede halswervel dicht bij het gewricht tussen de eerste en tweede halswervel.
De dorsale tak vormt de N.Occipitalis Major deze verzorgt de sensorische innervatie van de huid van de kruin regio en zorgt voor de motorische innervatie van de m.obliquus capitis caudalis. 

De ventrale tak splitst en vormt de N.Auricularis Magnus welke de sensorische innervatie van het gebied achter de kaak en het achterste deel van het oor verzorgt en de N.Transversalis cervicalis welke een connectie heeft met de aangezichtszenuw (N.Facialis).

Wanneer de zenuw die vanaf C2 komt, overprikkeld raakt door gewrichts irritatie van het gewricht tussen de eerste en tweede halswervel of door te hoge spierspanning kan er ernstige hoofdpijn ontstaan.

Afbeelding 1 Bron; Popesko Atlas of topographical anatomy

Oorzaken

Irritatie van de gewrichtjes tussen de eerste en tweede halswervel ontstaan door een ongunstige hoofd-hals houding.
Dit wordt vaak benoemd als ‘valse knik’.  Door deze houding ontstaat een ongunstige gewrichts mechaniek wat leidt tot overbelasting en irritatie van de halsgewrichten.

Afbeelding 2 Bron; Internet (bewerkt)

Hangen in het halster.
Wanneer het paard in het halster gaat hangen komt er veel druk achter op het hoofd en de eerste twee halswervels. Dit kan irritatie geven van het gewricht tussen de eerste en tweede halswervel.

Verhoogde spierspanning
Omdat de zenuw na uittreden tussen spieren doorloopt kan een verhoogde spanning van de spieren in de hoge hals maar ook van de M.Brachiocephalicus waar hij tussen de spiervezels doorloopt een overprikkeling geven en dus leiden tot hoofdpijn.
De spierspanning kan lokaal verhoogd zijn door ‘verkeerd’ spiergebruik, overbelasting en andere factoren.

Afbeelding M.Brachiocephalicus Bron; Popesko figure 154

Vallen of ander trauma kan leiden tot schade aan de halswervelkolom en betrokken structuren.

Wat te doen?
Vermoed je dat jouw paard last heeft van hoofdpijn als gevolg van problematiek in de halswervelkolom? Dan is het goed om in overleg met je dierenarts een bewegingsspecialist zoals dierfysiotherapeut, osteopaat of chiropractor in te schakelen.
Wanneer je paard gevallen is of overig trauma is het altijd belangrijk om een dierenarts te raadplegen.

Preventie
Liever nog worden dit soort problemen voorkomen daarom is een regelmatig preventief consult een aanrader, zo kunnen eventuele problemen al in een vroeg stadium herkend en verholpen of voorkomen worden.

Equine connections part 2
The head and neck position of the horse in training
Lieneke Gijsbertsen – Equine Osteopath (ICREO)

Over the last 25 years a lot has changed in the riding and training of the Icelandic horse.
Due to new insights and influences of different riding styles such as classical and english dressage, the way we ride and compete our horses has changed. Nowadays, we want a more round and collected frame in most gaits. In tolt, where we often saw a more hollow shape in the eighties and beginning of the nineties, we now appreciate a more round form with a different head and neck position. This article tries to address the different head and neck positions from a biomechanical perspective and translates this to a practical view on training.

The head and neck position (HNP) can significantly influence the movements and limb loading of the horse. As a rider and trainer, we define the head and neck positions of the horse and therefore are responsible for positive benefits and negative consequences.
For that reason knowledge of anatomy, biomechanics, and well-considered training are crucial in this matter.

Fig 1 : Head and Neck positions illustration by Matthias Haab

The described head and neck positions used in this article are:
HNP1: Free head and neck position
HNP 2: Neck raised, poll high, and bridge of the nose slightly in front of the vertical
HNP 3: Neck raised, poll high, and bridge of the nose slightly behind the vertical
HNP 4: Neck lowered and flexed, bridge of the nose considerably behind the vertical
HNP 5: Neck (extremely) elevated, and bridge of the nose considerably in front of the vertical.

The movements possible in the neck are flexion and extension, lateral flexion, and rotation. Flexion is the downward movement of the head or downward bending of the neck. Extension is the upward movement of the head or upward bending of the neck.
Flexion opens the joints and extension more or less closes the joint. Lateral flexion is the sideways bending of the neck and rotation is the turning of the head/neck. These two are always combined in functional movement.

In freedom the horse uses the head and neck positions for stability in movement. The slower the movements, the larger the range of motion in the neck. As the speed of the gait increases, the neck is held more rigid for stabilization due to co-activation of the neck muscles.

Fig.2 Spine of the horse

The cervical spine is supported by a ligamentous structure called the nuchal ligament.
This ligament consist of two thick cables of ligamentous structure fused together: the funicular part of the nuchal ligament, and a thinner part; the lammelair part of the nuchal ligament.

The nuchal ligament, along with the neck muscles, plays an important role in the biomechanics of the head and neck positions. This strong ligamentous structure is what supports the head and neck. It is attached to the poll, the withers, and continues over the back as the supraspinal ligament, which attaches at the sacrum. When the head goes down, the tension on this ligament increases so that when the horse is grazing the back is supported and lifted.

Fig.3 Nuchal ligament and supraspinal (or supraspinous) ligament.

We can use this leverage system to our advantage, when riding, to open the withers and lift the back.

All head and neck positions, except for position 5, are giving traction on the nuchal ligament.
In reference to biomechanics, this is an important fact.
Tension on this ligament will open the withers and lift the back, but can extend the lower back (lumbar spine). Therefore, if we are riding our horse in a round or lower form, tension on this ligament will open the withers and lift the back (thoracic spine), which would be something we aim for, for instance, in tolt. The FEIF sports regulations describing tolt state that:

“The horse should move in balance, with strong and active back and active hind quarters. The movements of the front part are light and free.”

If we want the front part to be light and free, we want the withers to be open. This will allow the well trained horse to be able to activate his core and thoracic sling muscles so as to lift his trunk between the withers and move freely from his shoulders.

Fig 4. Thoracic sling muscles

Because of the continuation of the ligament over the back to the sacrum, tension on this ligament will also mean that it will pull the lumbar spine into extension, and more or less close the lumbosacral joint (the joint between the lumbar spine and the sacrum).

The lumbosacral joint is the most mobile point of the back, working like a hinge joint for flexion and extension. In flexion it allows the hind legs to move under the horse. When pulled in extension, this will influence the capacity of the hind legs to step under in a negative way.

This mainly happens in head neck positions 3 and 4. In these head neck positions, the lumbar spine is pulled in extension by the supraspinal ligament. Therefore, the muscles of the hindlimbs have to work against this strain to be able to bring the lumbar spine into a more neutral position or towards flexion as needed, to bring the hindlimbs under. Mostly what happens, is that in an overly bent neck position, the strain on the ligaments will be high and as a consequence, the stride of the hind leg will get shorter because the hind legs will not be able to step under.

This is a misinterpretation commonly made, as we learned that riding in a hollow frame could be very harmful to the horse, and we began riding in a continuously more rounded shape. Of course, a rounder shape can open the withers, lift the back and therefore be beneficial for the horse, but in our goal to move away from the hollow frame, maybe we forgot to appreciate a more open frame?

Especially in young horses, the muscles of the hind are not strong enough to bring the hindlimbs underneath against the strain of the ligament, when ridden in a too-round bend position. Our main focus should always be on the hind legs, before we focus on the ideal head neck position.

Fig. 5 tension on the ligaments will facilitate the hind legs to stay behind

As we see in fig.1 HNP 3 and 4 the hind legs are left behind and the limb loading is mainly on the front legs.

In a position like HNP2, we enable the horse to lift the withers with the support of the ligament and neck muscles. Because of the activated neck muscles and the lighter stretch on the ligament, the lumbar spine is able to flex and the hind legs are able to step under without resistance. This is a position we see a lot in the higher tolt competitions. Riding in this position demands the horse to be trained and strong enough to activate his core and thoracic sling muscles so as to lift his thorax between the withers. When the horse isn’t strong enough, this position will push the withers down and shorten the stride length of the front legs (Fig 8). Unfortunately, we see this happening in tolt frequently.

Fig 6. Withers pushed down

In a position of HNP 3, the angle of the trachea is far from ideal. The horse can suffer from lack of oxygen as a consequence.

In a lower frame with longer topline like HNP 4 or a similar frame with the nose on the vertical, the weight of the trunk moves more forward and loads the forelimbs. In a fit horse, this frame can be part of training the thoracic sling muscles and lengthening the back muscles. However, if you have a horse recovering from a front leg injury, you want to avoid this extra load on the forelimbs.

When looking at HNP 5, there is no tension on the neck ligaments and in theory, the hind legs are able to step under, but in an too extended frame, the spine is compressed and the withers are pushed down. This can result in the stride length and timing being influenced in a negative way. Also, the spinous processes and the facet joints in the cervical spine are pushed towards each other in an extended frame, and as a consequence, the risk of back injuries increases.

So what is the right head and neck position?

At this point we might agree that HNP 3 is not favorable for the horse due to a possible lack of oxygen inflow. In young horses we might want to avoid HNP 4 because the hind quarters are not yet strong enough to move against the tension of the supraspinal ligament.

Looking at different head and neck positions, every position, when used at the right moment in training can have a beneficial training advantage. We have to consider that is the training advantage bigger than possible negative side effects. The important thing is to translate the different positions to your horse’s conformation and training goals. Also, we have to keep in mind that we may not want to focus on the head and neck position as a goal, but as a result of an engaged hind leg and collection.

Besides the biomechanical influence of the nuchal and supraspinal ligament, the various muscles of neck and trunk influence the capability of the horse to perform in different head and neck positions. These muscles fatigue quickly in a statical shape. It is advisable is to use varied head and neck positions as opposed to using just one head and neck position.

Want to learn more about this subject? Or feedback on this article?
Feel free to email me; Lienekefysio@gmail.com

References: Back,W & Clayton, H (2001) Equine Locomotion Velde van de, S (2018) De invloed van verschillende hoofdhoudingen op de beweging van het paard. Gomez Alvarez et al (2006)The effect of head and neck position on the thoracolumbar kinematics in the unridden horse. Elgersma et al (2010) A pilot study on objective quantification and anatomical modelling of in vivo head and neck positions commonly applied in training and competition of sport horses

 

 

Equine connections part 1

Lieneke Gijsbertsen – Equine Osteopath (ICREO)

The horse is an incredible athlete capable of amazing performance. Health is a crucial factor for any athlete in order to be able to perform at its maximum capacity.
Health, as described by the World Health Organisation, is a state of complete physical, mental, and social well being, and not merely the absence of disease.
We should always want to take great interest in how we can keep our equine athlete happy and healthy, so he can be on top of his game. As with human athletes, physical activity, athletic performance and recovery from exercise in horses is not just a factor of favourable genetics and training. The whole management of the equine athlete should be focused on its optimum wellbeing. Besides stable management, nutrition, and training, an equine therapist can make a significant contribution to overall athletic development, sports management, and health in your horse.

Osteopathy is an anatomy and physiology based form of manual therapy which looks at biomechanics and neurological connections within the horse. It emphasises manual readjustments, physical manipulations, muscle techniques and myofascial release.
The philosophy is based on the idea that any restriction in movement will lead to health deficits and injuries. Osteopathy is all about connections within the body and finding the restricting link.

A practical example
Recently I was called in for a four and half year old gelding with high expressive movements.

He was six weeks in training and had shown irregularities/ lameness on his left front leg mainly in trot. The vet could not find any reason for this lameness. The horse was in good overall health had a well considered nutrition plan and was trained by an experienced trainer.

The vet prescribed NSAIDs but the lameness did not improve. When i was called the horse was not on any kind of medication and appeared alert and happy.

In observation I noticed this was a horse with a lot of mobility in his body and huge movements. An important thing to remember is that all mobility should be stabilized by muscle control.

A thing i come across a lot in young Icelandic horses is that they have lots of mobility (sometimes hypermobile) but do not yet have the strength and muscle control to stabilise their movements and are therefore more likely to get injured. In observations he was clearly irregular on the left front in trot, and as expected it was worse on the lefthand circle.

Being an osteopath i do not focus so much on the visible problem (left front lameness in this case) as well as the possible cause of the physical problem. Because the physical problem we notice is often a result of restrictions elsewhere in the body.

When i checked his body i noticed three major restricted points,
● His lumbar spine was stiff and therefore he was not able to put his hind end completely under.
● The fascia of his lower back (fascia thoracolumbalis) was also restricted.
● There was a blockage of the lower neck.

Now i can hear you think, so how does this influence the left front leg? One way it did was by the m.latissimus dorsi, this is a muscle coming from the forearm and going all the way to the lower back

 

 

Fig 1. M. Latissimus dorsi

You might imagine that a restriction on the lower back fascia will limit the ability to length this muscle as it did in this specific case. As you can see the muscle is attached to the forearm of the horse. When the muscle cannot get to its full length it will restrict the forward movement of the leg.

Because of this restriction the m.latissimus dorsi was not able to make length on the left side, therefore the left shoulder was restricted in its movement which resulted in a shorter step on the left front.

Because of restrictions of the lumbar spine, the hind leg (especially right), was not able to step under and therefore the left front (since legs work in diagonal pairs) was loaded more than it should have.

So now we have a young horse with big movements with a shorter step and to much loading on the left front. Because of this shorter step a restriction of the lower cervical spine occured.

A blockage of the lower cervical spine influences the innervation and vascularisation of the shoulder. It’s like stepping on a hose while watering the plants.. water will still come out a bit
but not enough to keep the plants healthy.

So the combination of extra load bearing and shorter step resulted in this case in an overload and strain injury of the left shoulder.

The restricted flow caused by the neck blockage made it worse and obstructed the healing which led to recurrent lameness of the left front.

The aim of the treatment was to restore the movement in the lower back and neck.

A rehabilitation plan was made with the trainer.

After treatment the training consisted maily groundwork with emphasis on mobility and stability for the first week.

Within a week after treatment the lameness no longer visible.

Within three weeks after treatment the horse was vetcheked and approved.

These results can only be achieved by teamwork. In this case between vet, osteopath and trainer.

For the best results teamwork and complete management are required.

If you want an equine therapist for your horse make sure you ask the following questions;

1. Which education is followed by the therapist?

2. How many horses does the therapist see a week?

3. Who are his partners in teamwork?

4. Can the therapist provide with references?