Extensor Digitorum: Origin - lateral epicondyle of humerus. Insertion - extensor expansions of medial four digits. Action - extends medial four digits at metacarpophalangeal joints, extends hand at wrist joints.
The Muscle (/sɑrˈtɔəri.əs/) – the longest muscle in the human body – is a long thin muscle that runs down the length of the thigh in the anterior compartment. Its upper portion forms the lateral border of the femoral triangle.