[headline style=”1″ align=”center” headline_tag=”h2″]Why I Got This Book…
Normal and Abnormal Function of the Foot is a book I have always wanted to read. It was highly recommended to me amongst some of my colleagues. After taking several foot courses, I wanted to learn more about the compensatory motion of the foot and up the kinetic chain. This book did just that. In this post I am going to share the function of the foot during gait, a brief summary of the 4 most important joints you should be assessing, followed by what I learned and what you can apply clinically, and finally, closing remarks.
[headline style=”1″ align=”center” headline_tag=”h2″]Function of the Foot During Gait
The foot is important for gait and other movement such as the golfing, changing direction, walking on uneven terrain, and etc. However, this book primarily discusses the foot’s role during ambulation. For this reason, the foot is solely talked about in regards to walking. Keep in mind the function of the foot is context specific. Below I have described the basic functions of the foot during ambulation.
The function of the foot during gait is three fold:
Shock Absorber & Adapts to Terrain
Provides a Rigid Lever to Propel Off Of
Torque Converter (subtalar joint)
The function of the foot is context specific
[headline style=”1″ align=”center” headline_tag=”h2″]Brief Summary of the Foot
To foot has 4 joints that basically determine the function and clinical pathology. When the foot doesn’t have adequate range of motion in these joints or is moving at the wrong time, pathology occurs.
The 4 main joints you must assess are the ankle, subtalar, midtarsal, and 1st ray.
[headline style=”1″ align=”center” headline_tag=”h2″]What I Learned Clinically…
Below you will find some of the take home points that I learned to apply clinically. The majority of the information is discerning foot compensations and structural versus functional abnormalities.
[headline style=”1″ align=”center” headline_tag=”h2″]Congenital or Functional Compensation?
When you have a congenital limitation, the foot will lack motion in only one plane. For instance, if a patient has a forefoot varus (frontal plane limitation), this restriction will not show up in the sagital and transverse planes. Conversely, if an acquired deformity is present, the foot will be altered in all three planes, not just one plane.
In regards to the subtalar joint, to discern if it is functional or structural you must put the talus is neutral. From here you can discern by the relationship of the calcaneus to the bisection of the achilles what type of foot it is or isn’t. Below you can see an example of a patient with a left foot that is pronated which is a compensation from the rearfoot due to a structural abnormality.
[headline style=”1″ align=”center” headline_tag=”h2″]Rearfoot Structural or Functional?
[headline style=”1″ align=”center” headline_tag=”h2″]1st Ray Functional Or Structural?
The 1st ray also has congenital and functional limitations, too. In a normal 1st ray, the range of motion should be equal into dorsiflexion and plantar flexion. When the range of motion is greater in the plantar direction, a congenital 1st ray is developed, while if motion is greater dorsally, it is a metatarsus primus elevatus.
Congenital 1st ray motion can be discerned from acquired similarly to above. Congenital has full ROM while acquired will lack range of motion in one direction. For instance, an acquired plantar flexed first ray will lack motion into dorsiflexion while having excessive motion in the plantar direction.
The first ray needs great motion especially when the longitudinal axis of the mid tarsal joint can’t compensate for excessive pronation. When this can’t occur, the first ray needs to dorsiflex which alters the mechanics and overtime can lead to an acquired deformity or even hallux rigidus.
When the midfoot doesn’t have adequate mobility, the 1st ray will usually compensate.
[headline style=”1″ align=”center” headline_tag=”h2″]The Midfoot’s Importance
The midfoot has two axis’s. One lies oblique while the other is more longitudinal. The importance of this is that it allows the foot to compensate at the forefoot in an array of patterns and only at one axis or both. The foot is also able to invert or evert without having to move in the sagital or frontal planes. This is important because it gives the foot variability, especially when walking on uneven surfaces or even adjusting to congenital or functional limitations.
For the oblique axis to compensate, though, it needs the subtalar joint to pronate. Meanwhile, the longitudinal doesn’t need the rearfoot to unlock. However, more mobility is present with the subtalar joint is pronating in both axis’s. Clinically, if the midtarsal joint usually doesn’t have enough motion to compensate, you will see a compensation at the 1st ray as in the video above.
Having two axis’s at the midfoot allows the foot to adapt and compensate in an array of patterns.
In case you wanted to see the axis’s of the midtarsal joint, here is a quick video outlining its function and axis’s.
[headline style=”1″ align=”center” headline_tag=”h2″]Subtalar Joint Angle Matters
This was the first time reading and understanding that the angle of the subtalar joint axis is different among individuals. This matters clinically because if the axis lies more in the sagital plane, more inversion and eversion will be present. In contrast, if the joint lies more vertical, it will have more abduction and adduction.
I have made the mistake of thinking a patient didn’t have inversion or eversion of the subtalar joint so I would crank away to increase motion. However, I would probably guess that these patients had more motion in the transverse planes of abduction and adduction.
Just because a patient doesn’t have much inversion or eversion of the calcaneus doesn’t mean its pathological- they could have a vertically oriented STJ axis.
[headline style=”1″ align=”center” headline_tag=”h2″]Conclusion
Overall, this book didn’t disappoint. It covers everything from the functional anatomy, biomechanics, and compensations of the foot. I would highly recommend adding this books to your bookshelf to help you better understand the foot and it’s compensations. By the way, if you are interested in learning more about the foot you can claim this book by Clicking Here