الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
It is the major biochemical transducer that converts the
potential (chemical) energy into kinetic (mechanical) energy. It
is a pulling, not a pushing machine, therefore, a given muscle
must be antagonized by another group of muscles or another
force such as gravity or elastic control (Murray et al., 1996).
Structurally, there are three types of muscles : skeletal
muscle, smooth muscle, and cardiac muscle (Harold, 1986).
The muscle is one of the components of the motor unit which
consists in addition of : the motor neuron and its axon, the
peripheral nerve and the neuromuscular junction.
Myopathy is a muscle disease not related to a
demonstrable alteration in the innervation of muscle (Mastaglia
and Walton, 1990).
The Primary Myopathies Include:
A- Muscle Dystrophies :
The term dystrophy coined by Erb 111 1891 means
abnormal growth and is derived from the Greek trophe meaning
nourishment.
Muscle dystrophy is distinguished by four obligatory criteria:
- It is a primary myopathy. - There is a genetic basis for the disorder.
- The course is progressive.
- Degeneration and death of muscle fibers occur at
some stage in the disease (Dubowitz, 1989).
B- Congenital Myopathies:
They are characterized by:
1- Relatively non progressive course.
2- Muscle weakness is present at birth or appears in
the early childhood.
3- The muscle bulk is normal or reduced, there is no
muscle hypertrophy.
4- Skeletal abnormalities are common (Banker, 1986).
C- Mitochondrial Myopathies:
Certain genetic abnormalities of mitochondrial ongm
cause identifiable myopathic syndromes.