Teaching Function In Functional Anatomy

Function. It is the holy grail of physical therapy. We focus our efforts on understanding an individual's function - and how to make them function better.

Anatomy and physiology are taught to provide us with the foundations of function. However, both are traditionally taught as a mess of rote memorization of muscle origins and insertions, innervations and actions.

What is lost in the mix is the big picture view - that "Form Follows Function". If we can understand the function of the human body, the dynamic entity that it is, then the anatomical foundations make far more sense. This requires teaching functional anatomy based on, imagine this, function!

We all know that function varies significantly from individual to individual. But we also know that at any given time during human development, from cradle to grave, we have specific functional demands imposed upon us. It could be the demands of fighting gravity on a daily basis while living on planet earth, or the challenges faced while in utero. Our function will be reflected in our anatomical form.

Function begins in utero with the development of limb buds. Limb buds project anterolaterally for both upper and lower extremities, with our respective elbows and knees facing laterally. The upper limb bud rotates laterally, causing the medial aspect of the limb bud to face anteriorly. The lower limb bud rotates medially, causing the medial aspect of the limb to face posteriorly.

Dermatomes, sclerotomes, and myotomes develop along the way. But instead of being viewed as a curious and seemingly inconsistent conglomerate of swirling dermatomal patterns and diverse muscular origins and insertions, function tells us otherwise. Muscles that function together have similar innervations and spatial orientations defined by this limb bud rotation.

But it is more than just the rotation of limb buds that makes sense of all of this. Look at the human spine as another fine example of Form Follows Function. In utero, there is no need for a cervical or lumbar lordosis. The primary functional demands are defined by the inherent space limitations in utero - so spinal kyphosis is a necessity! But not long after birth, there is a functional demand of raising our head to feed and to see the world around us. These demands promote the development of a cervical lordosis. As we develop, there is soon a desire to sit and subsequently stand and walk. A lumbar lordosis is necessary to do so.

We are on a life-long health continuum. The human body adapts to the imposed functional demands: in sickness and in health, in chronic medical conditions and in elite performance. We are always shifting along this continuum dynamically, and sometimes more successfully than others. If we understand the functional demands at any given time along this health continuum, we can always establish what anatomical structures and physiological mechanisms will be required to successfully navigate a world of mechanical loading in a gravity-filled existence. Perhaps more importantly, it also tells us why we are not adapting to the imposed demands.

If we put function back into functional anatomy, it is amazing how the complexity of human anatomy is reduced to some elemental principles that remain consistent and will never lead us astray.

We can certainly continue to promote rote memorization and events on a developmental timeline – much as I was taught almost 30 years ago. But if our world is built on function, then we should teach it - from the most basic level - as such.

Photo credits: quapan

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