By Eleanor Andrews

One of the core concepts within osteopathic philosophy is the understanding of the total lesion concept. The total lesion concept identifies that the individual animal is created by the summation of its internal environments on the influence of the external environment which surrounds the individual. There are many different names applied to the triune of the internal environment but after years of training, clinical experience and teaching, I found the most useful to be that of biomechanical, physiological and psychological When discussing an animal patient.

How does this work?

The total lesion concept reminds us to consider all components within the individual animal and understand that each of these will influence the other and will impact the presentation of the patient in front of you. It also reminds us of the importance of the external environment which has an overarching influence on the internal situation of the individual.

The easiest way to depict this is by using a Venn diagram comprising 3 circles which overlap in the centre and which in turn are surrounded by a larger single circle.

The three circles represent the three components of the triune of the internal environment, with the centre which overlaps representing the individual animal. The animal is influenced by a combination of the three internal environments. The larger circle surrounding these components depicts the external environment and the impact it has on the animal within. The external environment may influence any or all of the three internal environments which in turn will influence the animal at the centre. In this way, the external environment exerts an overruling influence on the individual.

Resultantly, the animal is the sum of all its internal and external environmental influences and stressors, and as such, we must consider all within the total lesion concept.

If we consider in more detail the internal environment, we speak of the triune of biomechanical, physiological and psychological.

The Biomechanical component generally reflects the musculoskeletal system and its prime coordinator the nervous system.

The Physiological component is reflected in the endocrine and immune systems and their interaction with the visceral and nervous systems. 

Whilst the Psychological component relates to elements regarding the emotional and behavioural health environment of the individual. Psychological factors arise from a multitude of sources and are often linked to external events such as stress from environment/activity.

As you can see, the nervous system can be found in both the physiological and mechanical elements of the internal environment. Remember that the statement for each say reflects/ is reflected in. Therefore, this does not mean that the system it is only considered within the one internal environment heading.
Fore example, the nervous system contains both somatic and autonomic components and therefore is directly involved in both the mechanical and physiological elements (via the viscera, endocrine and immune systems).
We can consider the circulatory and respiratory system in a similar manner. Technically they come under the visceral systems and therefore link with the physiological element. However, they will also have mechanical influence on the animal. For example, reduced lung function will mechanically affect the ribs and the musculoskeletal system and in turn can be similarly affected by this system. Ligamentous and fascial connections will directly connect these systems with the musculoskeletal system. On the same note, physiologically, poor lung function will affect gaseous exchange and, combined with altered circulatory function will affect cell metabolism which will, in turn impact healing, repair, activity, exercise tolerance and the allostatic load of the animal which may lead to poor immune system and endocrine functioning and comorbidities/health complications.

As an animal osteopath it is important that I understand the idea of the total vision concept and the trying within the internal environment however that I also understand the intricacies of each system and their impact by mechanically, physiologically and psychologically in order to enable me to better understand the coordination and correlation of these systems within the animals body and both the local and global impact that any alterations to these will have.

In Part 2 of this blog, we will look more closely at the external environment and the impact that has within its influence over our animal patients.