The anconeus, an active lateral ligament of the elbow: new anatomical arguments.

PURPOSE: As there are a few detailed anatomical studies of the active function of anconeus muscle in stabilizing the elbow, we aimed to look for anatomical features confirming its role as an active stabilizer of the humero-ulnar joint.

METHODS

Thirty fresh unembalmed elbows from 15 cadavers were dissected. We examined the anatomy, insertions, relationships and orientation of the muscle fibres of the anconeus.

RESULTS

The anconeus lies in a separate compartment from the other forearm muscles, but in continuity with the extensor (triceps) compartment of the arm. In all the cases, at its proximal extremity we observed continuity of muscle and tendon with the vastus lateralis of the triceps brachii. The muscle fibres run downward and backward, parallel to the fibres of vastus lateralis of the triceps, when the elbow is in extension. Its deep aspect adheres closely to the lateral joint capsule of the humero-ulnar joint.

CONCLUSION

The new anatomical characteristics of the anconeus revealed in this study make this muscle a digastric head of triceps brachii that coapts the ulna to the humerus and so reduces varus instability. The close relationships between triceps brachii and the anconeus on one hand and between the joint capsule and the anconeus on the other make the latter muscle an active lateral stabilizer of the elbow.