Anatomical study of the innervation of the posterior elbow joint capsule: implications for ultrasound-guided peripheral nerve block and radiofrequency ablation procedures.

Abstract

Introduction: Ultrasound-guided peripheral nerve block and radiofrequency ablation have been developed for pain management in various joints including the hip, knee and shoulder, but not the elbow. Precise three-dimensional (3D) localization of the articular branches and landmarks visible on ultrasound are needed. The objectives of this anatomical study were to determine the presence, course, frequency, landmarks and areas innervated by the articular branches supplying the posterior elbow joint.

Methods: In 12 upper extremity specimens, articular branches to the posterior elbow joint were dissected from brachial plexus to termination. Origin, course, frequency, capsular distribution and landmarks were documented. Data were reconstructed into 3D models and a 3D frequency map to visualize spatial relationships between the articular branches, capsule and landmarks.

Results: The superior part of the posterior capsule was innervated by the ulnar collateral nerve (92%) and lateral branch to triceps (100%). The lateral part was supplied by the nerve to anconeus (100%) and, when present, branch to extensor carpi ulnaris (58%). The medial part was supplied by the ulnar nerve through direct branches (92%) and branches to forearm flexors (100%). The medial and posterior antebrachial cutaneous nerves supplied the medial and lateral epicondylar areas, respectively (100%, 83%). Common landmarks included the epicondyles, olecranon, olecranon fossa, and margins of triceps.

Conclusions: The 3D data of the articular branches supplying the posterior elbow joint provide an anatomical basis for the development of peripheral nerve block and radiofrequency ablation protocols to treat elbow joint pain. Further anatomical and clinical studies are necessary to identify target sites and evaluate the proposed landmarks in vivo.