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18 Cards in this Set
- Front
- Back
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Describe a concentric contraction |
- when a muscle contracts and shortens |
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What is a mover? |
-the muscle that is concentrically contracting |
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A muscle contractions that don't result in shortening are called: |
-eccentric contraction - isometric contraction |
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What is the difference between a mobile attachment and a fixed attachment? |
- if an attachment moves it is said to be the mobile attachment
- if the attachment of a muscle doesn't move it is fixed
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What is reverse action? |
When the attachment that is usually fixed becomes mobile and the attachment that is usually mobile is now fixed. |
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What is a fixator or stabilizer muscle? |
- a muscle that contracts to fix a body part |
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What does the direction that the muscle fibers run tell you? |
the direction of the muscle fibers relative to the joint it crosses tell you:
- the line of pull of the muscle relative to the joint - the line of pull will determine the actions of the muscle (how the contraction of that muscle will cause the body parts to move at that joint) |
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What questions should you ask IOT find out a muscle's action? |
1. What joint does the muscle cross? - if a muscle crosses a joint, then it can have an action at that joint - if a muscle does not cross a joint then it cannot have an action at that joint.
3. How does the muscle cross the joint? |
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What questions should you ask IOT find out a muscle's action? |
2. Where does the muscle cross the joint? -the where is whether is crosses the joint anteriorly, posteriorly, medially, or laterally -muscles that cross a joint anteriorly will usually flex a body part at that joint -muscles that cross a joint posteriorly will usually extend a body part at that joint -muscles that cross a joint laterally will usually abduct or laterally flex a body part at that joint -muscles that cross medially will usually adduct a body part at that joint |
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Notes about WHERE a muscle crosses a joint |
- flexion is nearly always an anterior movement of a body part -extension is nearly always a posterior movement of a body part -from the knee joint and farther distal, flexion is a posterior movement and extension is an anterior movement of the body part - abduction occurs at joints of the appendicular skeleton - lateral flexion occurs at joints of the axial skeleton |
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What questions should you ask IOT find out a muscle's action? |
3. How does the muscle cross the joint? -the how is whether it crossed the joint with its fibers running vertically or horizontally.
-a muscle that has a horizontal direction to its fibers (in the transverse plane) and wrap around the bone b/f attaching to it creates a rotation action when they contract and pull on an attachment |
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Describe the movement of a muscle w/ 1 line of pull in a cardinal plane |
-w/one line of pull that lies perfectly in a cardinal plane, the muscle will have one action (plus the reverse action of that action) |
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Describe the movement of a muscle with 1 line of pull in an oblique plane (pg 418) |
- the muscle will create movement in the oblique plane - each movement must be broken up into is names for ea. cardinal plane |
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Describe the movement of a muscle with more that one line of pull |
- for ea. line of pull that is oriented perfectly in a cardinal plane, there will be one action (along with the reverse of that action) - for ea. oblique line of pull, the movement that occurs in the oblique plane can be broken up into its separate cardinal plane components |
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Can a muscle choose which of its actions will occur? |
No, muscles are basically machines that contract when they are ordered to contract by the nervous system |
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What are two rules about muscle movement WRT lines of pull |
- a muscle w/ one line of pull attempts to create every one of its actions when it contracts - a muscle w/ one or more lines of pull does not necessarily attempt to create every one of its actions when it contracts. It may attempt to create the action (s) of one of its lines of pull but not the action(s) of another of its line of pull. |
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Can a muscle action change? |
- yes - the action is dependent on its line of pull RELATIVE to the joint that is crosses; therefore if the relationship of the muscle's line of pull to the joint changes, the muscle action changes. - this relationship can change if the position of the joint changes |
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what is anatomic action? |
- describes a muscle's action when the body is in anatomic position.
- this verbiage implicitly recognizes that a muscle's action on the body when the body is not in anatomic position may well be different from the action of the muscle when the body is in anatomic position. |
