In October 2021 I was lucky enough to attend the Centaur Biomechanics Equine Sports Seminar Virtual Summit. As always, the lectures were of a very high quality and there was an immense amount to take in. Here I share with you some of my understanding.
Dr Rikke Schultz has integrated holistic approaches to regular veterinary practice since studying veterinary medicine at the University of Copenhagen in 1992. She holds international exams in veterinary acupuncture, osteopathy and homeopathy.
Traditional anatomy describes muscles with origin, insertion and function. Kinetic lines are chains of interconnected muscles, fascia and other kinds of connective tissue. They describe motion through the whole body. Each muscle is connected to the next, and to the next, and so on, though the fascia.
The kinetic lines describe motion of the spine and the body, in terms of flexion, extension, lateral flexion, rotation, arm movements, and the relationship of the organ to the somatic body.
Thomas Myers was amongst the first to document the fascial lines in humans. To be a fascial line, the chain of muscles must have fibres going in the same direction, the function of the tissue must be the same, the depth of the tissue must be the same, and there must be a direct or mechanical connection. The human lines are the superficial back line, the superficial front line, the lateral line, the functional line, the spiral line, the deep front line, and four arm lines. In the equine / canine dissection, there are the superficial dorsal line, the superficial ventral line, the lateral line, the functional line, the spiral line, the deep ventral line, four front limb lines, and the deep dorsal line.
Fascia is contractile, and can stay contracted. It is also plastic, in that its structure can change if it’s contracted for a long period of time. This is what can lead to problems. The fascial lines never work alone, they always work in combination.
The superficial dorsal line creates extension of the neck, back and hip, and flexion of the hindlimb. The superficial ventral line creates flexion of the neck, back and hip, and extension of the hindlimb. The superficial dorsal line and the superficial ventral line are antagonists. They work together like a bow and string. They connect at the head where the fibres of the temporal muscle merge with the masseter muscle. They make work on the temporomandibular joint really important for the whole body, and also make dental work important. They connect into the hindlimb at P3, where both the flexor and extension tendons attach. This makes hindlimb foot stance, shoeing and trimming extremely important for the whole body.
The lateral line has a superficial and a deep layer in the horse. The superficial lateral line works more when the horse is in flexion, the deep lateral line works more when the horse is in extension. Again these lines come together around the temporomandibular joint. For the horse to be straight, there needs to be an equal tension through the lateral lines on each side of the horse.
The front limb lines consist of a protraction line and a retraction line as the main functions. There is also adduction and rotation in the protraction line, and there is abduction and rotation in the retraction line. The protraction and retraction lines are continually interacting with each other.
The helical lines include the functional line and the spiral line. Each has a dorsal and ventral part.
The functional line is involved in rotational movements, and may be part of the explanation of diagonal lameness. The dorsal part retracts the front limb and the contralateral hind limb, and rotates and extends the back (a trotting movement). The ventral part is an antagonistic flexor of the back. The right functional line starts at the right front limb.
The spiral line was the most complicated line to define and to dissect out. Different parts of the spiral line have different functions. The cranial part creates lateral flexion of the neck. The ventral part creates retraction of the front limb and protraction of the contralateral hindlimb, as well as rotation and flexion of the back. The dorsal part is an antagonistic extensor of the back and straightens the neck. The left spiral line starts at the left side of the head and ends at the right side. The spiral line is particularly relevant in walk and canter.
As an example of compensatory mechanisms involving fascial lines, Dr Schultz hypothesised that a horse with unilateral facet joint arthritis on the left could protect himself from pain and further damage through lumbar extension (using the superficial dorsal line) and lateral flexion (using the lateral line), which could lead to left front limb line contraction, which could affect the left front - right hind diagonal, which could lead to stifle problems, which could lead to shortening of the protraction of the left front, which could lead to suspensory ligament problems. This is one example of why it is so important to try to find the root cause of discomfort and movement dysfunction in order to help the horse to heal and return to function.
For more information, great webinars and a whole heap of relevant research, visit www.centaurbiomechanics.co.uk.
© Sue Palmer, The Horse Physio, 2021
Treating your horse with care, connection, curiosity and compassion