<P> A tendinous arch is frequently the origin of the long head and the tendon of latissimus dorsi . In rare cases, the long head can originate from the lateral margin of the scapula and from the capsule of the shoulder joint . </P> <P> The triceps is an extensor muscle of the elbow joint and an antagonist of the biceps and brachialis muscles . It can also fixate the elbow joint when the forearm and hand are used for fine movements, e.g., when writing . It has been suggested that the long head fascicle is employed when sustained force generation is demanded, or when there is a need for a synergistic control of the shoulder and elbow or both . The lateral head is used for movements requiring occasional high - intensity force, while the medial fascicle enables more precise, low - force movements . </P> <P> With its origin on the scapula, the long head also acts on the shoulder joint and is also involved in retroversion and adduction of the arm . </P> <P> The triceps can be worked through either isolation or compound elbow extension movements and can contract statically to keep the arm straightened against resistance . </P>

What actions does the triceps perform at the shoulder
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