The 3 Foot Shapes

The assessment of natural varus and valgus deformities is undertaken when the foot is in sub-talar joint neutral and the patient is non-weightbearing. Functional compensations for these natural deformities are revealed when the foot is fully weightbearing and in contact with the ground.

When the foot moves through the gait cycle, the disruption caused to the degrees and timing of pronation and supination interfere with proper foot function. The effects of this disruption are present not only within the feet, but because of the nature of the closed kinetic chain; compensations occur all the way through the body.

All feet can be categorised into one of three basic types, based on their appearance and altered function during static and dynamic weight-bearing stances (standing still and walking, respectively), as shown in the pie-chart below:

Normal foot types comprise around 30% of the total foot shape types within the general population. The Pronator and Supinator Types together represent abnormal foot shape types, and account for 70% of foot shapes within the general population. The table below identifies the main differences between these two abnormal foot types.

* denotes that this compensated deformity, although present may not always be visible, due to the nature of the relationship between the rearfoot and the forefoot. Professional assessment is required to determine this.

The above information shows clearly how natural varus deformities are by far the most common, accounting for 67% of all foot types. That means that around 7 out of every 10 of us are walking around with some type of natural varus deformity of the foot.

Just because around 70% of the population have some degree of inversion of the foot, this does not mean that 70% of the population are suffering dysfunction and pain throughout their lives. Whilst it is true that with the presence of a varus deformity the foot the rest of the musculoskeletal structure must adapt to compensate, it does not hold true that a similar degree of compensation in two different people will cause the same type and degree of dysfunction and pain.

A more severe degree of inversion (varus deformity) normally equates with a more severe degree of dysfunction and pain, but there are many other factors; such as the nature and relative degree of the inversion between the forefoot and rearfoot of each foot, age, lifestyle, genetics, occupation, level of fitness, hobbies and general health that determine on an individual level how a varus deformity affects the rest of the body. For some, a moderately severe problem may not yet be causing any noticeable problems, but in another a mild case may be causing severe pain.