Posture is simply the orientation of the body in space in response to both internal and external stimuli. Posture can optimise the function and performance of the musculoskeletal system, and performs a protective function either of the whole organism or of individual body parts and systems. Dr Narda Robinson recently presented a lecture titled ‘The Anatomical Underpinnings of Postural Changes in Dogs and Cats’. Here I share my take-home thoughts from that lecture.
What is Posture?
Posture is the position of a body in space. It is both static and dynamic and determines as well as is determined by the anatomical structures of the body. Posture will change in response to internal and external stimuli from the musculoskeletal system, visual stimuli, vestibular stimuli and sensory feedback from the skin.
Posture and function are closely connected. Posture can be used to optimise function or performance, with good posture allowing the musculoskeletal system to work together in the most energy-efficient and optimal manner. Posture can also aid in the protection of the whole animal, as can be seen during a fear, flight or fight response in all species. Localised pain or dysfunction will also elicit postural changes to protect the affected areas. In addition, posture is key to understanding the physical and mental state of an animal.
Postural control is an unconscious and autonomic response, occurring as a result of feedforward and feedback mechanisms between the musculoskeletal system, fascia and skin, and the central nervous system. Posture maintains the body in balance and protects its structures from injury, danger or progressive deformity as a result of gravity.
We cannot consider posture separately from the nervous system and its function. The central nervous system controls posture by relaying information to the muscles to initiate contraction and relaxation. The peripheral nervous system provides information from joint capsules, muscle-tendon units and fascial chains to allow continuous feedback and feedforward conversation that allows optimal postural control.
Postural Response to Injury
When an injury occurs, posture will change and adjust, resulting in pain, muscle hypertonicity in some areas and muscle hypotonicity in others, the imbalance of kinetic chains, and the loss of harmony in skeletal segments within the planes of movement.
Common postural adaptations to injury that we may see include kyphosis or lordosis of the spine, a lowered or raised head and neck position, rigidity of the spine, increased pelvic flexion, reduced or increased angulation of the limbs, abnormal weight bearing on the paws, and internal or external rotation of the hocks, elbows, or paws.
Observing Postural Changes
Postural assessment must be a part of our evaluation of every patient. We should take note of the posture of the patient in different positions, as well as in motion. As Narda Robinson said, ‘We want to pay attention to the dog from nose to tail and from topline to toes.’
When evaluating an animal in terms of posture, take note of the coat and direction of the hair; also notice the patient’s eyes and what they are looking at, the curvature of the spine, the placement of each of the feet, and tail position and carriage. All give clues to possible areas of pain or tension.
Dr Narda has developed some great mnemonics to remember the muscles that influence posture, in both the epaxial and hypaxial aspects of the spine, and in the neck and limbs. Some of the main muscles that she discusses as commonly affected include the
- sub occipitals
- quadratus lumborum
- psoas major
- psoas minor
When there are changes in the tonicity and mobility of these muscles, they will restrict and alter the patient’s range of motion significantly.
By visually assessing the dog’s posture, we can start to get a good idea of which muscles might be most affected by a change in tone or size, and which muscles may become painful with myofascial trigger points.
When we follow these observations with palpation, we will be able to identify pain, hypertonicity, and myofascial trigger points. In Dr Narda’s webinar, she shares a few case discussions, including the dog below.
In this patient, we see multiple significant postural adaptations, including:
- kyphosis of the lumbar spine
- flexion of the pelvis
- low and rigid head and neck position
- lowering of the center of mass
- increased flexion of the hip
- tension through the abdominal cavity
- change in breathing
- tightness through the chest
For a more in-depth discussion of this patient’s posture, movement and treatment, please watch the webinar!
A Myofascial Chain Perspective
As the Vet Rehab Summit is fast approaching, I want to challenge each of us to consider the myofascial chains in the patients we assess, and how they might be affected.
In this dog, we see evidence of an imbalance between the superficial and the deep dorsal and ventral muscle chains. In the superficial chains, the muscles of the neck including spinalis, splenius, and brachiocephalicus are shortened and tight, restricting the mobility of the neck. The ventral chain is shortened, creating a protective posture, while the dorsal chain is lengthened.
The deep dorsal and ventral chains include the psoas muscle complex and quadratus lumborum. In this dog, the muscles are shortened and will probably be painful. The diaphragm will also be affected, which will result in changes in breathing, changes in pleural pressure regulation, and potential changes in nervous system regulation.
When we consider the front limb protraction and retraction lines in a dog with the above posture, we will also see multiple changes. The muscles of the thoracic sling attaching the forelimb to the trunk will be shortened in an effort to reduce the mobility of the neck, and to stabilise the lower cervical area. This results in compression of the thoracic cavity which may impact the nerve roots of the brachial plexus, the breathing, and nervous system regulation. The stride will also become stilted and short.
Join us at the Vet Rehab Summit 2023
If you would like to learn more about myofascial chains and how they affect our patients, please join us at the Vet Rehab Summit 2023, where Vibeke Elbrond and Rikke Schultz will be joining us live for two days on 10 and 11 November, to take a deep dive into the fascia!