The purpose of this study is to evaluate anatomical variations of the coracoacromial ligament (CAL) in relation to the etiology of subacromial impingement syndrome and rotator cuff tears. A knowledge and understanding of these variations will help to determine how such variations may influence the surrounding tissues and how the biomechanics of the shoulder works, as well as improving accurate diagnosis and subsequent treatment of shoulder impingement syndrome. The methodological approach involved the dissection of 220 cadaveric shoulders in the Centre for Anatomy and Human Identification (CAHID) with a mean age of 82 years (range 53 to 102 years). The CAL was classified according to its morphology and composed band number. The rotator cuff tendons were inspected for tears that were categorized into partial bursal and complete tears. Furthermore, the study inspected the CAL’s parameters and attachment sites: degenerative changes include acromial and coracoid spurs and attrition lesions at the undersurface of the acromion. Results: the multiple banded ligament was the most commonly observed type and was seen in 101 (46%) specimens. The attachment sites of the ligament varied as the size or number of bands of the ligament increased. An association was found between rotator cuff tears and shoulders which had three or more CAL bands (52%). In addition, shoulders with rotator cuff tears had wider attachments, thicker ligaments and larger subacromial insertions. Shoulders with rotator cuff tears also had a significant incidence and size of acromial spurs. The size of the spurs was correlated with the size of the CAL and attrition lesions on the undersurface of the acromion, and changes in morphology of the acromion. Attrition lesions at the subacromial insertion of the CAL were associated with tears in the rotator cuff tendons, and worsened as the size of the subacromial insertion increased. In conclusion, anatomical variations of the CAL showed a relationship with rotator cuff tears.

Cette thèse s’est d’abord voulue pratique. La chirurgie de l’épaule est en pleine expansion avec le vieillissement croissant de la population et la pratique de plus en plus généralisée du sport. L’épaule est une articulation complexe. Paradoxalement les progrès techniques en chirurgie sont sans cesse grandissants et renouvelés tandis que l’on tientpour acquis des données anatomiques démontrées il y a longtemps et rapportées jusqu’à nos jours. Nous avons voulu confronter l’anatomie avec les techniques diagnostiques actuelles et voir si cela pouvait avoir un impact sur les pratiques chirurgicales. Nous avons également voulu voir si certaines complications chirurgicales pouvaient s’expliquer par des données anatomiques. Ce qui a orienté nos recherches sont les principaux problèmes actuels en pathologie de l’épaule c’est-à-dire la coiffe des rotateurs et le syndrome sous-acromial. Les observations lors des nombreuses dissections de l’épaule nous ont conduit à ces réflexions : comment la glène est-elle vascularisée?, pourquoi est-elle si fragile?, que se passe-t- il dans l’espace sous acromial?, quelle est l’utilité du ligament coraco-acromial?, quels sont ses rapports avec lesuprapinatus?, pourquoi l’insertion du supraspinatus est-elle fragile et difficile à reconstituer ?, la qualité osseuse de la tête humérale a-t-elle un impact sur la géographie des fractures, les échecs des ostéosynthèses, les descellements prothétiques?, qu’est ce que la chape delto-trapézoidienne? Autant de questions que nous nous sommes posées endisséquant cette articulation très complexe qui est l’épaule. Par ailleurs, l’anatomie classique peut maintenant secompléter non seulement de l’histologie, mais aussi de techniques radiologiques modernes comme l’IRM l, le microCT, le synchrotron, la reconstruction 3D, la modélisation en éléments finis. / I would like to make a practical thesis. Shoulder surgery is growing and growing as the population is ageing and people is doing more and more sports activities. A lot of technical progress were done but there are still a lot of surgical complications. On the other way some very old anatomical ideas are still alive. I want to see with the actual knowledge, if some surgical complications could be explained by anatomy. Subacromial pathology and bone quality remain the two mainproblems of shoulder surgery and pathology. That’s what had suggested to me this study about the shoulder. I was supposed to analyze glenoid bone first .The aim was to know more about arterial supply of glenoid. That was my firststudy (article 1). Then, I was interested in glenoid bone quality. And the second study had appeared. (article 2). During the shoulder dissection, I was looking for the fascia delto-trapezoidal which I didn’t found as described in books. It was my third study. (article 3). Going on I found the coraco-acromial ligament and I was surprised to see the constant portion under the acromial process. And that gave me the idea for the fourth study. (article 4).As I had discovered the very interesting technique of micro-Ct densitometry, I would like to apply it to the humeral head bone. There was the fifth study. (article 5)But, I want to know more and more about bone quality and I went on with the greater tuberosity and especially the area ofsupraspinatus insertion. The insertion and the sub-chondral bone were analyzed. There’s the last but not least study!(article 6). I was really interested in supraspinatus muscle and tendon and I want to follow the course of the muscle as the zone of conflict. I was the subject of study in life as I went through RMI . The muscle was reconstructed as finite element. Then it was possible to describe the zone of conflict with the supraspinatus. Here’s the seventh article. (article 7)