HUMERORADIAL “MENISCUS”: ANATOMY, HISTOLOGY AND PATHOGENIC DEDUCTIONS FOR LATERAL EPICONDYLALGIA

Abstract

Purpose: A fibrous element between the radial capitulum and the fovea is classically described; it is often called a synovial fringe. The term “meniscus” has been proposed to designate a truly rigid peripheral structure partially inter-postioned between the joint surfaces and susceptible of producing joint disease by internal disregulation of repeated pronation supination movements. This led us to study the anatomic and histological properties of this intra-articular structure.

Material and methods: Fifty adult cadaver shoulders were dissected. The en bloc resection included the capsule of the humeroradial joint and the entire annular ligament. We searched for a fibrous structure, noting its soft or rigid aspect, its position relative to the five-part segmentation of the capsuloligament resection, and its size and thickness. Vertical sections were made for the histology study to determine the organized connective tissue or synovial nature of the structure.

Results: An intra-articular element was visible in 43 cases, two structures were observed in two cases, on the deep aspect of the junction between the capsule and the annular ligament. The main positions observed were: circular (n=3), lateral and posterior (n = 11), posterior (n = 10). The anterior (n = 4), or lateral (n = 5) positions were rare. Mean length was 21.4 mm (9–51), mean width between the capsular attachment and the free edge was 2.9 mm (1–10), maxiam mean thickness was 1.7 mm (1–4 mm). The histology report showed two types of structures: a rigid structure with an oriented fibrous armature that had a triangular peripheral base continuous with the superior border of the annular ligament and covered with synovial on both sides of the free edge; a soft flexible structure formed uniquely by two layers of synovial and a more or less villous free edge. Fibrochondroid structures of the meniscal type were not observed. Small nerve fibers were demonstrated in some cases.

Discussion: Certain lateral epiconylalgias of the elbow would suggest involvement of the humeroradial joint, possibly related to injury of the humeoradial “mensiscus”. This study points out the frequency of this synovial or fiborsynovial fringe of variable dimensionts interpose between the radial capitulum and fovea. The structure has a more or less marked connective armature, basically in the lateral and posterior portion, and correctly cannot be termed a “meniscus”. This structure might be involved in inflammatory and painful syndromes observed in epicondylalgias of the humeroradial joint.