لخّصلي

Muscles
There are three types of muscle :
Skeletal
Smooth
cardiac
1.
2.
3.
Muscles that produce the movements of the
skeleton
Made of striped muscle fibres.
Have two or more attachments, that which
moves least, referred as origin , and that which
moves the most as insertion,
Have fleshy part referred as belly,
Attached to bones by fibrous tissue known as
tendon, or by strong sheet of fibrous tissue
called aponeurosis, tendinous interdigitation of
the fibrous ends of flat muscles is called raphe.
Skeletal (Voluntary) muscles
University Of Tripoli 12
Classification of skeletal muscles
Muscles
Pennate muscles, fusiform muscles, flat
muscles, quadrate muscles,strap and circular.
Prime mover, Antagonist, Fixator, Synergist .
Pennate muscles: mucles whose fibres run
obliquely to the line of pull (resemble a
feather), there are
Unipennate muscle: tendon lies along one
side of the muscle and muscle fibres pass
obliquely eg. Extensor digitorum longus
Bipennate: tendon lies in the center of the
muscle and the muscle fibres run to it from
two sides.eg. Rectus femoris
Multipennate: tendon lies in the center of the
muscle and the muscle fibres run to it from all
direction. eg Tibialis anterior , or as a serious of
bipennate muscle eg deltoid

1. According to their shape:


2. According to their action:

Types of skeletal muscles according to
their action
Prime mover: The chief muscle or group of
muscles responsible for a particular movement
eg. Quadriceps femoris is a prime mover in the
movement of knee extension
Antagonist: muscle that opposes the action of
prime mover eg. The biceps femoris opposes
the action of quadriceps femoris, and before
the prime mover can contract the antagonist
must relax equal and this brought about by
nervous reflex inhibition.
Synergist: when prime mover crosses a
number of joints before it reaches the joint at
which its main action takes place, groups of
muscles called synergist contract to prevent
unwanted movements in an intermediate joint.
eg. The flexor and extensor muscles of the
carpus contract to fix the wrist joint, to allow
the long flexor and extensor muscles of the
finger to work efficiently.
NB: These terms applied to particular
movement , many muscles can act as primover,
an antagonist, a fixator or a synergist,
depending on the movement to be
accomplished
Fixator:
Muscle that contract isometrically (no
movement) to stabilize the origin of the
primover.
So, it can act efficiently eg. Muscles attach the
trunk to shoulder girdle contract to allow the
deltoid to act on the shoulder joint.
University Of Tripoli 13
Muscles
University