Circle the word or words that best describe how you are feeling right now.

What do you need from me (your teacher) to do your best in class today?

Compare and contrast origins and insertions of a muscle.

List two professions in which it might be helpful to know the origins, insertions, and actions of muscles.

Consider the sternocleidomastoid muscle (shown below is the right sternocleidomastoid):

The sternocleidomastoid muscle is named after its origin and insertion. It originates at the sternum (sterno-) and clavicle (-cleido-) and inserts at the mastoid process (-mastoid).

Remember that the origin of a muscle does not move when a muscle contracts, while the insertion does move.

Match up the following actions, considering the information above.

For flexion of the neck, the sternocleidomastoids are agonists, or prime mover. This means that they are a main muscle in completion of the action. Complete the action, and think about your sternocleidomastoid muscles contracting as you do it. The muscle that would complete the oppositve action (extension of the neck) is called the antagonist.

Using the diagram below, determine which muscle is the most likely to be the antagonist of the sternocleidomastoid muscles in neck flexion. (I.e. - which of the following muscles is most likely to extend the neck?)

Consider the following image comparing the biceps brachii and triceps brachii.

Now, consider the origins and insertions for each:

Biceps brachii

Origin: coracoid process

Insertion: radial tuberosity

Triceps brachii

Origin: posterior of humerus

Insertion: olecranon process of ulna

THINK about the movements, then classify the following actions and labels for each muscle:

Consider the following image comparing the origins and insertions of the rectus femoris (left, anterior view) and the biceps femoris (right, posterior view)

Feel for these processes and muscle attachment sites on your own body.

Think about it: What will happen when the biceps femoris contracts? What will happen when the rectus femoris contracts?

Pick TWO opposing movements (actions) from the textbook of the muscles of the Head, Neck and Back.

Write the actions, agonist muscles (prime movers), origins, and insertions in the table in the "show your work" box below. These can be found in the table in the textbook.

Finally, visit the GetBodySmart website. Find the two muscles for your actions. Take a screenshot of both and place them in the "show your work" box below the table.

Pick TWO opposing movements (actions) from the textbook of the muscles of the Shoulder and Upper Limb

Write the actions, agonist muscles (prime movers), origins, and insertions in the table in the "show your work" box below. These can be found in the table in the textbook.

Finally, visit the GetBodySmart website. Find the two muscles for your actions. Take a screenshot of both and place them in the "show your work" box below the table.

Pick TWO opposing movements (actions) from the textbook of the muscles of the Hip and Lower Limb

Write the actions, agonist muscles (prime movers), origins, and insertions in the table in the "show your work" box below. These can be found in the table in the textbook.

Finally, visit the GetBodySmart website. Find the two muscles for your actions. Take a screenshot of both and place them in the "show your work" box below the table.

Pick TWO opposing movements (actions) from the textbook of the muscles of the Abdominal Wall and Thorax. You will likely need to reference the page for the Head, Neck, and Back.

Write the actions, agonist muscles (prime movers), origins, and insertions in the table in the "show your work" box below. These can be found in the table in the textbook.

Finally, visit the GetBodySmart website. Find the two muscles for your actions. Take a screenshot of both and place them in the "show your work" box below the table.

What do you understand about origins, insertions, and actions?

What questions do you still have about origins, insertions, and actions?