Learning Modules - Medical Gross Anatomy
Movements of the Upper Limb - Page 5 of 18
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Learning Modules - Medical Gross Anatomy |
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Arm Abduction | |
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Abduction of the arm is also called abduction of/at the shoulder. This motion actually can be divided into two motions: true abduction of the arm at the shoulder and upward rotation of the scapula. Muscles: supraspinatus (initiates abduction - first 15 degrees), deltoid (up to 90 degrees), trapezius and serratus anterior (scapular rotation, for abduction beyond 90 degrees). |
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The deltoid muscle abducts the arm, but at 90 degrees the humerus bumps into the acromion. Beyond this point, further abduction is the result of upward scapular rotation. | |
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| Copyright© 2000 Thomas R. Gest. Unauthorized use prohibited. |