Role Of Coracoid Morphometry In Subcoracoid Impingement Syndrome

摘要

INTRODUCTION : Subcoracoid impingement syndrome is a less common cause of shoulder pain. It occurs when the subscapularis tendon impinges between coracoid and lesser tuberosity of the humerus. The variations in height and length of the coracoid process are held responsible for altering the shape of the space between coracoacromial arch and rotator cuff. Apart from these, other morphometric parameters of the coracoid process may also play some role.MATERIALS AND METHODS: The study was conducted on 100 dry scapulas (R:L = 50:50) obtained from The Department of Anatomy, Government Medical College, Amritsar. Different parameters such as length, breadth, height, thickness of the coracoid process, height of the supraglenoid tubercle to the under surface and superior surface of the coracoid process as well as coracoglenoid distances were measured. The mean values were calculated and compared with the earlier studies. An attempt has been made to discuss the role of these parameters in causation of subcoracoid impingement syndrome.RESULTS: The mean values for different parameters as observed in the present study were mean length = 40.43 mm, breadth = 13.77 mm, height = 15.62 mm, thickness = 7.83 mm, height of supraglenoid tubercle from under surface of the coracoid process = 15.18 mm, height of supraglenoid tubercle from superior surface of the coracoid process = 21.59 mm and coracoglenoid distance = 27.05 mm.CONCLUSION: Our study provides a base line data for different morphometric parameters of thr coracoid process and discusses the role of these parameters in the aetiology of subcoracoid impingement syndrome which will be helpful in the management of the same to the orthopaedician. Introduction The geometric anatomy of the scapula is of fundamental importance in the pathomechanics of rotator cuff disease, total shoulder arthroplasty and recurrent shoulder dislocation1. The mechanical impingement on the rotator cuff by the overlying acromial arch and the possibility of rotator cuff impingement by its anteromedial part i.e. the coracoid process was postulated as early as 19092. The coracoacromial anatomy includes the acromion, the coracoacromial ligament, and the tip of the coracoid process3. It is the variation in the height and length of the coracoid process which is responsible for altered size and shape of the space between the coracoacromial arch and the rotator cuff4. It has also been suggested that the problem is functional with anterior instability leading to a narrowing of the coracohumeral distance5.The subcoracoid space is occupied in vivo by several soft tissue structures, such as the articular capsule of the gleno-humeral joint, the subscapularis tendon and the subacromial bursa. The thickness of these tissues may vary but variations are small and do not affect the width of the subcoracoid space unless there is local pathology. The shape and size of this space depends on its limiting skeletal structures2,6. Therefore, anatomical morphometric studies of these structures may provide information as to the aetiology of the subcoracoid impingement syndrome.The coracoid process also forms an important part of the scapular glenoid construct and is involved in many surgical procedures on the glenohumeral joint7. Its detailed morphometry is useful in surgical procedures such as hardware fixation, drill hole placement and prosthetic positioning8. Congenital variations and minimal traumatic/iatrogenic changes in this orientation can predispose to subcoracoid dislocation7. Materials and Methods The material for the present study comprised of 100 adult scapulae of unknown sex and age, obtained from the department of Anatomy, Government Medical College, Amritsar, Punjab, India. These were labelled from 1-100 with suffix R (right) or L (left). Of the 100 bones, 50 were of the right side and 50 were of the left side. All the bones were free from any physical deformity or abrasion and were complete in all respects. The following parameter