SPINAL CORD
s in u s e s , f a c ia l) ;
c h a n n e l s
f o r
t h e
o p t ic
n e rv e
a n d o t h e r n e r v e s ; a n d a s p a c e f o r
t h e
p it u it a r y g la n d .
s p h e ro c y to s is , h e re d ita ry
A n
i n h e r i t e d
d i s o r d e r
i n w h i c h
t h e r e
a r e a l a r g e n u m b e r o f u n u s u a l l y s m a l l ,
r o u n d r e d b l o o d c e l l s
( s p h e r o c y t e s )
i n
t h e c i r c u l a t i o n . T h e s e a b n o r m a l c e l l s a r e
f r a g i l e
a n d
e a s i l y
b r o k e n
u p
w h e n
b l o o d
p a s s e s
t h r o u g h
t h e
s p le e n .
A t
t i m e s , t h e r a t e o f r e d b l o o d c e l l d e s t r u c -
t i o n
(h a e m o ly s is )
e x c e e d s
t h e
r a t e
a t
w h i c h n e w
c e l l s
c a n
b e
m a d e
i n t h e
b o n e m a r r o w , l e a d i n g t o
a n a e m ia
.
SYMPTOMS
T h e
c h a r a c t e r i s t i c
s y m p t o m s
o f a n a e -
m i a ,
s u c h
a s
t i r e d n e s s ,
s h o r t n e s s
o f
b r e a t h , a n d p a l l o r , m a y d e v e l o p . O t h e r
s y m p t o m s
i n c l u d e
ja u n d ic e
( y e l l o w i n g
o f t h e s k i n a n d w h i t e s o f t h e e y e s ) a n d
e n l a r g e m e n t o f t h e s p l e e n . O c c a s i o n a l l y ,
c r i s e s o c c u r ( u s u a l l y t r i g g e r e d b y i n f e c -
t i o n )
i n
w h i c h
a l l
o f t h e
s y m p t o m s
w o r s e n .
G a lls t o n e s
a r e a f r e q u e n t c o m
-
p l i c a t i o n o f h e r e d i t a r y s p h e r o c y t o s i s .
DIAGNOSIS AND TREATMENT
T h e d i a g n o s i s o f s p h e r o c y t o s i s i s m a d e
b y b l o o d t e s t s .
S p le n e c t o m y
( r e m o v a l o f
t h e s p l e e n ) u s u a l l y l e a d s t o p e r m a n e n t
i m p r o v e m e n t .
Spherocytes in blood
A person with hereditary spherocytosis has a large
number of these unusually small, round, fragile,
red cells in the blood.
s p h in c te r
A r i n g o f m u s c l e a r o u n d a n a t u r a l b o d y
o p e n i n g o r p a s s a g e t h a t r e g u l a t e s i n f l o w
o r o u t f l o w , s u c h a s t h e a n a l s p h i n c t e r .
s p h in c te r, a r t ific ia l
A
s u r g i c a l l y
c r e a t e d
v a l v e
o r
o t h e r
d e v i c e u s e d t o t r e a t o r p r e v e n t u r i n a r y
o r f a e c a l
in c o n t in e n c e
.
s p h in c te ro to m y
A s u r g i c a l p r o c e d u r e t h a t i n v o l v e s c u t -
t i n g
a
s p h in c t e r
m u s c l e
t h a t
c l o s e s
a
b o d y o p e n i n g o r c o n s t r i c t s t h e o p e n i n g
b e t w e e n b o d y p a s s a g e s .
TYPES OF SPINA BIFIDA
There are different forms of spina bifida. In one type (spina bifida occulta), the
only defect is a failure of the fusion of the bony arches behind the spinal cord.
When the bone defect is more extensive, there may be a meningocele, with
protrusion of the meninges (the membranes surrounding the cord) or, more
seriously, a myelocele, with malformation of the spinal cord itself.
MENINGOCELE
MYELOCELE
Meningocele
In this type, of spina bifida, the nerve tissue
of the spinal cord is usually intact; there is
skin over the bulging sac and therefore there
may be no functional problems. However,
repairs are necessary early in life.
Myelocele
In this type of the condition, the baby is born
with a raw swelling over the spine. It consists
of malformed spinal cord, which may or may
not be contained in a membranous sac. The
child is likely to be disabled.
s p h y g m o m a n o m e te r
A n
i n s t r u m e n t
f o r
m e a s u r i n g
b lo o d
p r e s s u re .
A c u f f a t t a c h e d t o t h e d e v i c e i s
w r a p p e d
a r o u n d
a
p e r s o n ’s
a r m
a n d
i n f l a t e d
u n t i l
i t
c o m p r e s s e s
t h e
m a i n
a r t e r y
i n
t h e
a r m ;
i t
i s
t h e n
d e f l a t e d
w h i l e t h e u s e r l i s t e n s t o t h e b l o o d f l o w
w i t h a s t e t h o s c o p e . D e p e n d i n g o n t h e
d e v i c e u s e d ,
t h e
b l o o d p r e s s u r e
m
e a -
s u r e m e n t m a y b e r e a d o f f a g r a d u a t e d ,
m e r c u r y - f i l l e d g l a s s c o l u m n , a g r a d u a t -
e d d i a l , o r a d i g i t a l d i s p l a y .
s p id e r b ite s
A l m o s t
a l l
s p i d e r s
p r o d u c e
v e n o m ,
w
h i c h t h e y u s e t o k i l l t h e i r p r e y . O n l y
a f e w s p e c i e s , s u c h a s t h e b l a c k w i d o w
i n
N o r t h
A m e r i c a ,
a r e
h a r m
f u l
t o
h u m a n s , h o w e v e r .
A n t iv e n o m s
a r e a v a i l -
a b l e
a s
a n
a n t i d o t e
f o r
m a n y
o f t h e
p o t e n t i a l l y f a t a l s p i d e r b i t e s .
s p id e r n a e v u s
A r e d ,
r a i s e d p i n h e a d - s i z e d d o t ,
f r o m
w h i c h a n u m b e r o f s m a l l b l o o d v e s s e l s
r a d i a t e . A s p i d e r n a e v u s i s f o r m
e d b y a
d i l a t e d m
i n o r a r t e r y a n d i t s c o n n e c t i n g
c a p i l l a r i e s .
S m a l l
n u m b e r s
o f
s p i d e r
n a e v i
a r e
c o m
m
o n
i n
c h i l d r e n
a n d
p r e g n a n t w o m e n ,
b u t
l a r g e r
n u m b e r s
m a y i n d i c a t e l i v e r d i s e a s e .
s p in a b ifid a
A
c o n g e n it a l
d e f e c t
i n
w
h i c h
o n e
o r
m
o r e
o f t h e
v e rte b ra e
f a i l s t o
d e v e l o p
c o m
p l e t e l y i n a f e t u s . A s a r e s u l t , w h e n
t h e b a b y i s b o r n a p o r t i o n o f t h e
s p in a l
c o r d
i s
l e f t
e x p o s e d .
S p i n a b i f i d a i s a
t y p e o f
n e u r a l t u b e d e fe c t
.
s p in a l a n a e s th e s ia
I n j e c t i o n
o f
a n
a n a e s t h e t i c
i n t o
t h e
c e r e b r o s p i n a l f l u i d i n t h e s p i n a l c a n a l
t o
b l o c k
p a in
s e n s a t i o n s
b e f o r e
t h e y
r e a c h t h e
c e n tra l n e rv o u s s y s te m .
S p i n a l
a n a e s t h e s i a i s u s e d m a i n l y d u r i n g s u r -
g i c a l p r o c e d u r e s o n t h e l o w e r a b d o m e n
a n d l e g s a n d i n o b s t e t r i c s . ( S e e a l s o
e p i-
d u ra l a n a e s t h e s ia .)
s p in a l c a n a l d e c o m p re s s io n
s e e
d e c o m p re s s io n , s p in a l c a n a l
.
s p in a l co rd
A c y l i n d e r o f
n e rv e
t i s s u e , a b o u t 4 5 c m
l o n g a n d a b o u t t h e w i d t h o f a f i n g e r ,
t h a t r u n s f r o m t h e
b ra in
d o w n t h e c e n -
t r a l
c a n a l
i n
t h e
s p in e
t o
t h e
f i r s t
l u m b a r v e r t e b r a . B e l o w t h a t p o i n t , t h e
l o w e s t n e r v e r o o t s c o n t i n u e w i t h i n t h e
c a n a l
a s
t h e
c a u d a e q u in a .
T h e
s p i n a l
c o r d i s a m
a j o r c o m
p o n e n t o f t h e
c e n -
tra l n e rv o u s s y s t e m
.
S
705
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