WALKING
w a lk in g
M o v e m e n t o f t h e b o d y b y l i f t i n g t h e f e e t
a l t e r n a t e l y , b r i n g i n g o n e f o o t i n t o c o n -
t a c t w i t h t h e g r o u n d b e f o r e t h e o t h e r
s t a r t s t o l e a v e i t . A p e r s o n ’s g a i t ( s t y l e o f
w a l k i n g ) i s d e t e r m i n e d b y b o d y s h a p e ,
s i z e , a n d p o s t u r e . T h e a g e a t w h i c h c h i l -
d r e n f i r s t w a l k v a r i e s e n o r m o u s l y .
W
a l k i n g
i s
c o n t r o l l e d b y n e r v e s i g -
n a l s t o t h e m u s c l e s . T h e s i g n a l s t r a v e l
t o t h e m u s c l e s , v i a t h e s p i n a l c o r d , f r o m
t h e m
o t o r c o r t e x o f t h e b r a i n ( s e e
c e r e -
b r u m ) , b a s a l g a n g lia ,
a n d
c e re b e llu m
.
DISORDERS
A b n o r m a l g a i t m a y b e c a u s e d b y j o i n t
s t i f f n e s s ,
m u s c l e w e a k n e s s
( s o m e t i m e s
d u e t o c o n d i t i o n s s u c h a s
p o lio m y e lit is
o r
m u s c u la r d y s t ro p h y ),
s k e l e t a l a b n o r m -
a l i t i e s
( s e e , f o r e x a m p l e ,
a rt h rit is ; b o n e
t u m o u r
;
h ip , c o n g e n it a l d is lo c a t io n of; s c o l-
io s is ; t a lip e s ).
A p a i n f u l l i m p m a y b e d u e
t o a f r a c t u r e o r d i s e a s e o f t h e l e g b o n e s
( t h e
tib ia ,
t h e
f ib u la ,
o r t h e
f e m u r ).
C h i l -
d r e n m a y d e v e l o p
k n o c k -k n e e
o r
b o w le g ;
s y n o v it is
o f t h e h i p a n d
P e rt h e s ’ d is e a s e
a r e a l s o c o m m o n . A d o l e s c e n t s m a y d e -
v e l o p a p a i n f u l l i m p
d u e t o a s l i p p e d
e p i p h y s i s ( s e e
fe m o ra l e p ip h y s is , s lip p e d ) .
A b n o r m a l g a i t m a y a l s o b e c a u s e d b y
n e u r o l o g i c a l
d i s o r d e r s
s u c h
a s
s tro k e
( c o m m o n l y c a u s i n g
h e m ip le g ia ), m u ltip le
s c le r o s is , p a r k in s o n is m ,
p e r i p h e r a l
n e u r i-
tis ,
v a r i o u s f o r m s o f
m y e litis ,
a n d
ch o re a .
M e n ie r e ’s d is e a s e
m a y c a u s e s e v e r e l o s s o f
b a l a n c e a n d i n s t a b i l i t y .
w a lk in g a id s
E q u i p m e n t f o r i n c r e a s i n g t h e m o b i l i t y
o f p e o p l e w h o h a v e a d i s o r d e r a f f e c t i n g
t h e i r a b i l i t y t o
w a lk.
S u c h a i d s i n c l u d e
s t i c k s , c r u t c h e s , a n d f r a m e s .
w a lk in g , d e la y e d
M o s t c h i l d r e n s t a r t t o w a l k b y a r o u n d
1 5 m o n t h s o f a g e . D e l a y e d w a l k i n g m a y
b e s u s p e c t e d i f t h e
c h i l d i s u n a b l e t o
w a l k
u n a s s i s t e d
b y
t h e
a g e
o f
1 8
m o n t h s ( s e e
d e v e lo p m e n ta l d e la y ).
w a rfa rin
A n
a n tic o a g u la n t d ru g
u s e d i n t h e p r e v e n -
t i o n a n d
t r e a t m e n t
o f a b n o r m a l
b lo o d
c lo ttin g .
W a r f a r i n i s u s e d t o
t r e a t d e e p
v e i n t h r o m b o s i s ( f o r m a t i o n o f a b l o o d
c l o t w i t h i n t h e d e e p - l y i n g v e i n s o f t h e
l e g ; s e e
t h ro m b o s is , d e e p v e in ), p u lm o n a ry
e m b o lis m
( a
f r a g m e n t
o f a b l o o d
c l o t
t r a v e l l i n g i n t h e b l o o d s t r e a m b e c o m i n g
l o d g e d i n t h e l u n g s ) , a n d p e o p l e w i t h
a tria l f ib rilla t io n
( a n a b n o r m a l i t y o f t h e
h e a r t b e a t )
w h o
a r e
a t
r i s k
o f
a n
e m b o lis m .
I t i s a l s o p r e s c r i b e d t o p r e v e n t
e m b o l i f r o m d e v e l o p i n g o n r e p l a c e m e n t
v a l v e s ( s e e
h e a rt-v a lv e s u r g e r y ).
A f a s t e r - a c t i n g a n t i c o a g u l a n t , s u c h a s
h e p a rin ,
m a y a l s o b e p r e s c r i b e d f o r t h e
f i r s t
f e w
d a y s
f o l l o w i n g
a
d e e p
v e i n
t h r o m b o s i s o r p u l m o n a r y e m b o l i s m .
W a r f a r i n m a y c a u s e a b n o r m a l b l e e d i n g
i n d i f f e r e n t p a r t s o f t h e b o d y , s o r e g u l a r
t e s t s
a r e
c a r r i e d
o u t
t o
a l l o w
c a r e f u l
r e g u l a t i o n o f d o s a g e . W a r f a r i n m a y a l s o
c a u s e n a u s e a , d i a r r h o e a , a n d a r a s h .
w a rt
A
c o m
m o n ,
c o n t a g i o u s ,
a n d
h a r m l e s s
g r o w t h
t h a t
o c c u r s
o n
t h e
s k i n
o r
m u c o u s m e m b r a n e s . O n l y t h e t o p m o s t
l a y e r o f s k i n i s a f f e c t e d . A n o v e r g r o w t h
o f c e l l s
i n
t h i s
l a y e r
c a u s e s
a
v i s i b l e
l u m p t o d e v e l o p .
CAUSES AND TYPES
W a r t s a r e c a u s e d b y t h e h u m a n p a p i l l o -
m a v i r u s , o f w h i c h a t l e a s t 7 0 d i f f e r e n t
t y p e s a r e k n o w n . T h e s e c a u s e d i f f e r e n t
W
THE MECHANICS OF WALKING
Many different muscles take part in the walking process.
brain. Feedback of information from the muscles and joints
They contract in a complex, rhythmic sequence in response
to the brain helps to ensure that the gait is smooth, steady,
to programmes of signals sent from the motor cortex in the
and coordinated.
Route of the signals
The signals for walking originate in the
motor cortex and are carried via the
spinal cord and nerve fibres to muscles.
I
As the left foot touches the
ground, the right arm swings
forward and the right foot shifts
on to tiptoe.
2
Once the left foot is fully
planted on the ground
and supporting the body,
the right foot is raised.
3
A sequence ofmuscle
contractions advances the
right leg, and the left arm
swings forward.
800
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