Introduction to Human Anatomy Sanjaya Adikari Department of Anatomy.
Naming muscles according to their action Sanjaya Adikari Department of Anatomy Faculty of Medicine...
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Transcript of Naming muscles according to their action Sanjaya Adikari Department of Anatomy Faculty of Medicine...
Naming muscles according
to their action
Sanjaya Adikari
Department of Anatomy
Faculty of Medicine
Peradeniya
Origin and insertion
• Origin – Proximal attachment where there is less movement
• Insertion – Distal attachment where there is greater movement
• Use the terms, proximal/ distal attachment to avoid confusions
Prime mover & antagonist
• Prime mover is the muscle that does the desired
movement at a joint
• Antagonist is the muscle that has the action
opposite to that of prime mover
• Eg:- Flexion of the elbow joint
– Biceps brachii is a prime mover
– Triceps is the antagonist
Prime mover & antagonist…
Synergist
• Synergist assists the prime mover by preventing
unwanted movements at other joints
• Eg:- Flexion of the fingers
– Flexor digitorum profundus and superficialis are
the prime movers
– Extensor muscles of the wrist joint are the
synergists
Synergists…
Synergists…
• Eg:- Supination of the pronated forearm
Biceps brachii and spinator are the prime movers
Triceps acts as a synergists of biceps to prevent
flexion of the elbow joint
Synergists…
• Eg:- Flexion of the elbow joint
Biceps brachii is a prime mover
Posterior fibres of deltoid acts as a synergist to
prevent extension of the shoulder joint
Fixators• Fixators stabilize one
attachment of a muscle so that the contraction moves the other end
• Eg:- Abduction of the shoulder joint
– Deltoid is the prime mover
– Levator scapulae, rhomboids and trapezius are fixators
Fixators…
• Eg:- Abduction of the little finger
– Abductor digiti minimi is the prime mover
– Flexor carpi ulnaris acts as a fixator of pisiform bone