The triceps brachii (three-headed upper arm) muscle is a large muscle of the back of the upper arm. It is the primary muscle used for elbow extension (straightening the arm).
Trigger points occur in all three heads but referred pain from the long head is the most common. Referred pain from the long head occurs up and down the back of the arm and to the lateral (outside) epicondyle (bony bump) with a spill-over pattern between the shoulder and neck. Trigger points in the lateral head refer to the middle, back of the upper arm, and may include the fingers. The medial head refers to the medial (inner) epicondyle, forearm, and fingers. The anconeus referral pattern is small, focused on the lateral epicondyle.
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