Hello everyone! This is Matt from Kenhub, and in this tutorial, we will discuss the anconeus muscle, its origin, innervations, and function.
The anconeus muscle is a small triangular muscle located at the elbow. It originates at the dorsal side of the lateral epicondyle of the humerus, and the fibers of the origin tendon also connect with the dorsal joint capsule. The muscle, then, inserts at the olecranon of the ulna. Here, again, you see the muscle highlighted in green and see how it’s connected at its origin and insertion.
The anconeus is easily palpated at the dorsal lateral side of the forearm because it is located superficially. If you place your fingers on the dorsal lateral aspect, just distal to the elbow, you can feel it. And it will be more pronounced if the forearm extends with resistance.
The anconeus is supplied by a motor branch of the radial nerve which arises at the radial sulcus of the humerus, continues through the medial head of the triceps, and finally reaches the muscle distally.
Shown here from the anterior view, you can see the radial nerve extending through the forearm. Both morphologically and functionally, the anconeus is really a continuation of the triceps. Not only are they supplied by the same nerve, but both muscles are often either partly or completely blended together.
The anconeus does essentially the same job the triceps does when it comes to the elbow. Its contraction leads to the extension of the forearm. Furthermore, it supports the tension of the dorsal joint capsule, thus, preventing damage during hyperextension. It is believed that the anconeus has the additional function of stabilizing the ulna, especially when the forearm is pronated.