Triceps is the muscle that is located below deltoid muscle and its inserted in the olecranon process of ulna. This muscle do have three origins and one insertion.
Step-by-step explanation:
Triceps is the muscle that is responsible for the extension of elbow joint and also contribute to extension of shoulder joint. This muscle have three origin, that's why the name triceps. The triceps muscle has three heads which are:
A. The long head originates from the infraglenoid tubercle of scapula.
B. The lateral head originates from above the radial Grove in humerus.
C. The medial head originates form below the radial Grove in humerus.
These heads meet to form the body of triceps which gets inserted as triceps tendon in the olecranon process of ulna just behind the elbow. The contraction of this muscle causes the extension of the elbow joint.