I often receive questions concerning the head/ neck position of horses during training. They are about multiple concerns as: ‘How long/ low/ round’ etc. It seems that controlling the neck position gives us a feeling of control and safety. We don’t like horses that buck us out of the saddle and therefore like to limit their ability of going ‘wild’ and feel that controlling the head/ neck position is a way to do that. Then there is also a visual factor. Neck posture often is a fashion and we like our horses to look ‘fancy’. But what about function?
The anatomy of the neck is complex as it is a big 'connection' part between the head and the shoulder. For the purpose of this blog I will elaborate on its anatomy and function in healthy biomechanics in a simplified way. The neck houses the trachea, oesophagus, spinal cord, blood vessels, fascia, ligaments, muscles, and 7 (C1-C7) cervical vertebrae. C1-C2 – Atlas and Axis – are mostly concerned with supporting and moving the head. C3-C5 are some of the largest vertebrae in the horses’ body and are labelled as the ‘typical’ cervical vertebrae. C6-C7 are both slightly different, for they provide insertion points for muscles arising from the chest. To support and move the vertebrae, it anchors more than a 100 muscles.
The neck has 2 functions I’d like to highlight:
- Its a vessel for routing crucial nerves around the body
There are multiple nervous systems in the horse. For the purpose of this post I will only mention the major one that runs through the neck. The Central Nervous System (CNS) is the ‘computer’ of the horse consisting of the brain and spinal cord. The spinal cord runs through the cervical vertebrae all the way to the tail. Also, a major nerve at the frond end of the horse, the Brachial Plexus, originates from the ventral branches of C6. A healthy neck is crucial for these nerves to function properly which in turn is crucial for healthy biomechanics.
- It serves as a balancing entity
Horses are masters in counterbalance! Ever seen a horse running flat through a corner like it’s a racing motorbike and wondering how it’s possible it manages to stay up and not fall over? It’s because they counterbalance using their neck! When horses fall in or out on the shoulder, they can use the weight of their head/ neck to counterbalance so they still manage to stay up. We can also experience this during training. It is therefore that inside bend is a really difficult concept for the horse as it contradicts their natural response.
So the neck is very important, yet often compromised. What can be the causes of this?
- The missing Nuchal Ligament Lamelle (NLL)
The nuchal ligament consists of the funicular cord at the top of the neck and the lamelle which is a ‘sheet’ like structure. Together it is also described as the ‘neck band’ which stabilizes the base of the neck and the weight of the head by countering the effect of gravity while cervical muscles are engaged and restrains the movement of the dorsal spines (lamellar).
When learning from anatomy books, the nuchal ligament lamelle is believed to be present all the way from C2-C7. However, in her studies, renowned pathologist Sharon May-Davis found that the nuchal ligament lamella was missing on C6/C7 in domesticated horses (all breeds/ages). The absence is present at birth and does not regenerate throughout the years. This leaves a distinct gap in supportive caudal neck tissue, leaving the base of the neck less supported and stabilized then textbooks might make us (unintentionally) believe. In the words of Sharon: ‘Its just like looking at a suspension bridge with support cables missing’.
Interestingly, dissections of a Donkey, Zebra, Preszwalski, Konik and Bosnian Mountain Horse (more primitive breeds) did show the lamelle all the way from C2-C7. This raises questions about the way we breed horses nowadays.
- Congenital malformation of C6/C7
Sharon May-Davis is also the first person to research and publish on this issue which is often still not known. It concerns a skeletal malformation from birth on the last two cervical vertebrae which can’t be corrected. It can cause pain, biomechanical issues due to its lack of anchor points for major muscles, neurological issues and the horse is less stable in general (more prone to fall and having a harder time to find balance).
- Trauma / Diseases
Unfortunately the neck can host many other
(congenital) conditions like:
- Spinal cord compression Spinal ataxia/ Wobbler’s syndrome and paresis
- Osteoarthritis (Cervical Intervertebral Facet Joints) & Arthropathy (Caudal Cervical Articular Process Joints)
- Osteochondrosis (OCD)
- Neck threadworms they actually live in the nuchal ligament!
It is important to note that some of these conditions might even be (partially) caused/ have a connection to the missing NLL and C6/C7 malformation.
Also, never forget interconnection! Problems around the head, shoulder but also in the hind can work on the neck and vice versa.
Apart from conditions, accidents can also happen. Trauma like flip-over, hitting obstacles, biting accidents and even more innocent acts like hanging in the halter. Such impacts can even fracture the vertebra which can then also cause spinal cord damage.
- Lateral asymmetry
Naturally, every horse has a preferential side for flexing and bending due to asymmetry in the musculature. One side of the muscles can easier shorten and contract while the other side finds it easier to lengthen and stretch.
Horses are often trained with overflexed (too short & round) overbended (more lateral bending in the neck than in the body) or overreached (neck too long or low) necks, compromising the biomechanics of the horse.
As said before the neck is a major balancing entity. Knowing that most of our horses actually lack major structures to support this function (missing NLL) it relies mostly on surrounding muscles to support the base of the neck. In my previous blog (FB page Thirza Hendriks) I already wrote about the importance of the thoracic sling and the Serratus Ventralis muscle.
Going up from the thoracic sling to the dorsal side of the neck, we find the fibres of the Serratus Ventralis muscle intertwine with the Rhomboid muscle. The Trapezius muscle lies on top of the Serratus Ventralis muscle. Both muscles lift the shoulder and assist in lifting the base of the neck. If these muscles contract, the base of the neck will be forced downwards. If they stretch, it will lift the base and flex the neck, assisting the ‘telescoping’ ability of the neck. On the ventral side of the neck we can find the Longus Colli and the Scalenus muscle. Both muscles flex the neck. The Longus Colli has an extra task in fixating, rotating and stabilising the vertebrae. When both contract together they help raise the base of the neck from below giving the dorsal muscles more leverage. In horses with a C6/C7 malformation the Longus Colli is often compromised as normal insertions there are not possible.
If we overflex or overbend our horse, we put considerable strain on these muscles and they won’t be able to perform their function properly. Then, the base of the neck will drop down loading the shoulders and pushing the sternum forwards. Because the front end is blocked (often asymmetrical as well), there is no space of the hind legs to step forwards to and they will start moving with more extension then flexion resulting in a ‘backwards’ motion disengaging the pelvis and blocking the back muscles to do their job as well, leaving the spine unprotected and unable to arch and carry our weight properly. But also asking the asking the neck long and low can result in ‘overreaching’ when the base of the neck is not supported to carry the heavy weight of the neck putting more stress on the front limbs which can result in dropped fetlocks and a disengaged pelvis.
Apart from interfering with the muscles needed for balance we can also compress important nervous pathways, which could lead to headshaking, excessive and local sweat patches on the neck and even lameness’s.
Therefore, instead of worrying about how to control the neck as a single entity, we should think in the entire chain. It’s only then that we can start to realize that a healthy neck position is not something we can create mechanically, but which will arise organically if we simply allow and coordinate the conditions of healthy interaction. Making sure that the thoracic sling is engaged, supporting and interacting with the ventral and dorsal muscles described above, in turn supporting the base of the neck and lifting the withers and ribcage. This will create space for the hind legs that will create a vertical force which the back muscles can coordinate. Then the degree of collection will determine the degree of arching and ‘telescoping’ the neck. We feel the horse reaching to our hand and simply allow and then balance, self-carriage and lightness will occur!
As with all my blogs I can’t give exact tailor-made practical advise on paper but here are some general tips that might help you to ensure a healthy functioning neck:
- ADRESS THE CAUSES, NOT THE SYMPTOMS. It might be argued that some horses chooses ‘bad’ positions themselves. This might be the case but when so, there ALWAYS is an underlying reason. Sometimes its repeating behaviour from the past. If its asked in a overflexed position in the past they might choose it because it’s the only thing it knows and therefore feels safe. Sometimes there are underlying issues that are compensated for by the neck. For example: Hypertrophy in the Rhomboid might be due to hind lameness whereas the Trapezius might indicate a front limb issues from the knee down. There can be many more reasons. By forcing your horse into a certain position anyway we’re covering up the causes for the benefit of a good picture.
- OBSERVE & PALPATE. Is the neck musculature symmetrical to both sides? Is the neck more convex or concave shaped? Is there any atrophy or hypertrophy on the trapezius or rhomboid muscles?
- INVEST IN YOUR TACK. A bad fitting saddle can directly compromise the muscles around the base of the neck, limiting the horse’s capability to use and balance it properly.
- BREATH & RELAX. Muscles can’t perform their functions properly when there is stress. They will tighten instead of stretching and contracting. So always prioritize full relaxation before asking anything from your horse.
- MAKE MANAGEMENT CHANGES. Feeding your horse from different positions and heights will help to increase flexibility, and balance. Especially higher positions will help to strengthen the muscles needed to support the base of the neck.
So look at your horse. Feel your horse. Ask for help or guidance if you’re struggling. Your horse will be thankful.