What is the proximal attachment of the anconeus muscle?

The anconeus muscle is primarily attached to the lateral epicondyle of the humerus. This muscle is small and triangular in shape, located at the elbow joint, and plays a role in extending the forearm. The attachment to the lateral epicondyle allows it to contribute to the movement of the elbow as well as provide stability during extension.

In contrast, the other options represent different anatomical locations relevant to other muscles but not to the anconeus. The medial epicondyle of the humerus is associated with several flexor muscles of the forearm, while the infraglenoid tubercle of the scapula serves as an attachment point for part of the triceps brachii. The coronoid process of the ulna is the insertion point for muscles like the brachialis and also provides a surface for ligaments but does not serve as the proximal attachment for the anconeus. Thus, the proximal attachment to the lateral epicondyle is significant for understanding the muscle's role in arm movement and stability at the elbow.