lab-manual-muscular-shoulder-arm-atlas.pdf

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2 PRE LAB EXERCISES Before coming to lab, get familiar with a few muscle groups we’ll be exploring during lab. Using Visible Body’s Human Anatomy Atlas, go to the Views section. Under Systems, scroll down to the Muscular System views. Select View 11. Shoulder, and find the following muscles. When you select a muscle, note the book icon in the content box. Selecting this icon allows you to read the muscle’s definition. 1. Pectoralis major 2. Latissimus dorsi Define the following terms: 1. Extension 2. Flexion 3. Abduction 4. Adduction 5. Rotation Straightening a part to where the angle between them increases and the parts move farther apart Bending parts so the angle becomes decresed and the parts become closer moving a part away from the midline moving a part toward the midline Moving a part around in an axis Downloaded by Larry Parmelo (gb4jrjr5wt@privaterelay.appleid.com) lOMoARcPSD|11715870

3 IN LAB EXERCISES Use the following modules to guide your exploration of the shoulder and arm regions of the muscular system. As you explore the modules, locate the muscles on any charts, models, or specimen available. These muscles are located in and act on the shoulder and arm regions. Because the glenoid cavity of the scapula is shallow and does not snugly fit the head of the humerus, the tendons of multiple muscles are involved in securing and stabilizing the humerus at the shoulder to prevent dislocation. Other muscles will cross the shoulder (glenohumeral) joint and insert on the arm, causing the arm to move when they contract. Movement of the brachium, or upper arm, depends on the fixators of the shoulder to keep the scapula in place so the arm can move freely. Once we move down into the antebrachium (forearm) and hand, the muscles begin to get smaller and more numerous, which grants us our fine motor skills when we write or play the piano. Pay attention to whether the muscle is on the anterior or posterior side of the arm – muscles on the anterior side will flex, while muscles on the posterior side will extend. The long names of some of these muscles can be daunting, but they are often very descriptive. You can find origins, insertions, actions, and/or locations of these muscles simply in the names. When reviewing the action of a muscle, it will be helpful to think about where the muscle is located and where the insertion is. Muscle physiology requires that a muscle will “pull” instead of “push” during contraction, and the insertion is the part that will move. Imagine that the muscle is “pulling” on the bone or tissue it is attached to at the insertion. Access 3D views and animated muscle actions in Visible Body’s Human Anatomy Atlas, which will be especially helpful to visualize muscle actions. When you select a structure in the Atlas app, you’ll see options to read the definition and hear the pronunciation in the content box. When you select a muscle, be sure to select the blue pin icon in the content box. This will give you the option to view origins and insertions as visible pins on the muscle (select Attachments), view the blood supply, and/or the nerve supply. In each module below, identify the following: • Muscle location • Origin(s) and insertion(s) • Muscle action • Nerve supply Downloaded by Larry Parmelo (gb4jrjr5wt@privaterelay.appleid.com) lOMoARcPSD|11715870

4 A. Muscles of the Shoulder Muscles of the Shoulder View the following Muscle Actions: Shoulder flexion Shoulder extension Shoulder horizontal abduction Shoulder horizontal adduction Shoulder abduction Shoulder adduction Shoulder medial rotation Try performing these actions yourself and feel which muscles contract. These muscles primarily act to stabilize the scapula and move the arm. Since the scapula is a moveable bone, it must be stabilized in order for the arm to be able to move. Some of these muscles are prime movers of the arm. They all cross the shoulder joint to insert on the humerus. Remember that muscles pull, and imagine how the muscle will pull on the humerus as it contracts. Shoulder lateral rotation Scapula elevation Scapula depression Scapula abduction Scapula adduction Scapula upward rotation Scapula downward rotation Downloaded by Larry Parmelo (gb4jrjr5wt@privaterelay.appleid.com) lOMoARcPSD|11715870

5 View 11. Shoulder Deltoid Pectoralis major Latissimus dorsi Downloaded by Larry Parmelo (gb4jrjr5wt@privaterelay.appleid.com) lOMoARcPSD|11715870

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