The triceps are a group of three muscles located in the back of the upper arm. They are responsible for extending the elbow joint and helping to stabilize the shoulder joint. The places where the triceps are located are the humerus, the ulna, and the scapula. The humerus is the long bone in the upper arm, the ulna is the smaller bone on the opposite side of the arm, and the scapula is the triangular bone in the shoulder.