The deltoids move the upper arm up and away from a neutral position at the side. They each have three different major regions, each with different attachment points around the shoulders. Each of these regions moves the a... More »

There are two math terms that find a middle value; one is the mean, or average. The formula for mean is ∑x / n. The other type of center to a set of data is the median. The median has no single formula for all situations... More »

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The biceps and triceps muscles are used to bend and extend the arm, while the deltoids are the muscles that lift the arm. When the bicep muscle contracts or flexes, it bends the forearm toward the shoulder. When the tric... More »

The function of the triceps brachii muscle is to extend the arm at the elbow joint. Located on the back of the upper arm, the triceps brachii consists of three bundles: the long, lateral and medial heads. The triceps bra... More »

The function of the biceps brachii muscle is to help the arm to bend at the elbow, according to WebMD. The muscle does this by extending and contracting as it moves back and forth. More »

The deltoids are the muscles that allow humans to raise their arms laterally. In addition to the deltoids, there are several other muscles groups that assist in lateral motion. More »

While both the pectoralis major and pectoralis minor muscles control the movements of the arm, the pectoralis major is specifically responsible for its lateral, vertical and rotational movement. In addition to this prima... More »