FIBROUS ARCHITECTURE OF THE DORSAL APONEUROSIS OF THE THUMB

Background: The extensor apparatus of the thumb displays obvious struc tural variations in its proximo-distal expanse, Its associated tissue comes in close relation to the dorsal aponeurosis that have varying to pographical relationships to the extensor apparatus of the thumb, This region is especially important as the location of pathological and re pair processes, Methods: In this anatomical study using a modified emb edding technique a histological description of the fibrous architectur e of the dorsal aponeurosis and the peritendinous connective tissue bo dy of the thumb is presented. Results: The dorsal connective tissue of the thumb forms different layers of collagen lamellae as a peritendin ous system around the tendons of the long and short extensor tendons o f the thumb, This peritendinous laminar system as the main part of the dorsal aponeurosis is connected with both the capsular and the retina cular ligaments of the thumb. Conclusions: It will be shown that the s tructural variations of the dorsal aponeurosis and peritendinous conne ctive tissue are an expression of different topographical zones of str ess along the Lines of a balanced musculofibrous stabilization of the interphalangeal joint of the thumb. The expansions in the peritendinou s intercellular space act as defined gliding spaces or clefts of the e xtensor apparatus. (C) 1995 Wiley-Lies, Inc.