Question

Describe a specific action (depression of the mandible for example) and then using your list of muscles, introduce the concepts of agonist, antagonists, and synergists to the movement. You should include the names of specific muscle of each functional group.

Answer 1

Action : shoulder flexion
Muscles involved ( flexor muscle group)
Main: pectoralis major, anterior head of deltoid .
Accessory: coroco brachialis, short head of biceps brachii.

Agonist muscle : anterior head of deltoid muscle
Antagonist: latismus dorsi

Agonist is deltoid, antagonist is the latissimus dorsi. When the muscles contract across the shoulder it push the shoulder upward into flexion. When opposite action happens the antagonist becomes deltoid and the latissimus dorsi becomes agonist.

Synergists during shoulder flexion
Agonist : prime mover : pectoralis major, ant deltoid
Synergists: pectoralis minor, middle deltoid serratus anterior
Antagonist: prime mover: latismus dorsii
Synergists: post deltoid