Ankle foot mechanism its biomechanics .pdf

ankle joint

1. S U B M I T T E D T O : D R . T A R A N G S I R V A S T A V A ( P T )
S U B M I T T E D B Y : P R I Y A R A J ( M P T F I R S T Y E A R )
ANKLE FOOT
MECHANISM

2. CONTENTS

•Introduction
•Types
•Non – dynamic response type
•Dynamic response type

3. INTRODUCTION
•The prosthetic foot is the foundation of all the prosthesis
except partial foot amputation
•It should serve the following features :-
1.Stimulate joint motion and muscle acting in normal foot
allows planter flexion , dorsiflexion , inversion ,eversion &
smooth roll over from ‘heel contact’ to ‘toe off’.
All prosthesis feet provides some degree of planter flexion b
but few provides only degree of inversion or eversion
2.To stimulate muscle activity ,the prosthetic foot substitute for
muscle action primary to the stance phase stability
3.It provide a stable base of support. The foot must stabilize
the body during the stance phase of the gait.

4. PROSTHETIC FEET CAN BE DIVIDED INTO TWO
MAJOR CATEGORIES
1.Dynamic response (energy conserving type)
2.Non dynamic response type
:- feet are manufactured in a wide variety of juvenile
& adult size

5. NON DYNAMIC RESPONSE TYPE

SACH FOOT
(Solid Ankle Cushion Heel)

6. •SACH foot is non articulated device with a solid wood or Al. heel ,
a sponge rubber heel wedge and a moulded cosmetic forefoot.

•Planter flexion stimulated by compression of heel wedge i.e.
adjustable to the pt. weight & activity level, there is no dorsiflexion,
inversion or eversion

•Mostly used throughout the world.

7. SINGLE AXIS FOOT

8. •Allow limited dorsiflexion or planter flexion by mean of
bumpers made up of hard rubber
•Does not medio – lateral rotation or motion
•At heel strike planter flexion bumpers compresses offering a
true planter flexion motion
•The rapid foot flat increases knee extension and prosthetic
stability on stance
•Dorsiflexion is little then the planter flexion bumpers limits
dorsiflexion at mid stance and terminal stance.

9. DYNAMIC RESPONSE TYPE

•Energy conserving type
•They are developed initially for pt. who wanted to
be active and perform activities such as running or
jumping
•The feet have flexible heel that increases shock
absorption & push off
•As pt. walk faster or run they spend more time on
fore foot then the heel thus increases planter flexion

10. SEATTLE FOOT

11. •Increases shock absorbing papered leaf springily
that absorbs energy at heel contact and release it
in terminal stance , thereby providing population

•The faster the cadence the more energy is
absorbed then release

12. FLEX FOOT
•It is the lightest and springiest of dynamic foot , it is
more suitable for pt. who walks at varying speed .
The foot is covered with foam to stimulate like
normal foot.