Morphological Variants and Dimensional Analysis of Human Acromion Process

Introduction: The acromion process forms the highest part of the shoulder and projects over the glenoid cavity. Morphometric details of the acromion process of scapula are of great significance since it is commonly involved in the impingement syndrome of the shoulder joint. The anterior third of the acromion process, the coracoacromial ligament and the coracoid process form the coracoacromial arch. Morphological variations of the acromion process & its relationship with the glenoid cavity and coracoid process is the most relevant factor determining the height of subacromial space. Material and Methods: The observations study is done on the basis of classification of acromion process given by Bigliani. The study was conducted on sixty-four dry adult human scapulae of unknown age and sex with a view to elucidate the morphological and osteometric details. Morphological and osteometric measurements of acromion process were studied and compared with the previous studies. Results: Based on morphological appearance, Type 1 (flat) acromion process was observed in 43.8% on right and 21.9% on left side. Type2 (curved) acromion was found in 50% on right side and 59.4% on left sided scapulae. Type 3 (hook shaped) acromion was observed in 6.3% cases on right side and in 18.8% on left sided scapulae. The length of acromion process on right side was found to be 46.23?5.48mm and it was found to be 44.89?4.71 mm on left sided scapulae. Mean breadth of acromion process was found to be 23.98?2.31 and it was found to be 23.27?2.28mm on right and left side respectively. Mean acromioglenoid distance was found to be 28.57?2.95mm on right side and 29.26?5.25mm on left side. Conclusion: The knowledge of the data with reference to shape and various distances of acromion process is useful to orthopaedic surgeons while carrying out surgical repairs around shoulder joint. In the present study, we have taken other morphometric measurements into consideration. With the help of the morphometric measurements, it is possible for orthopaedic surgeon operating on the shoulder to place the prosthesis accurately. Additionally, these parameters may assist in understanding the etiopathogenesis of rotator cuff tear and impingement syndrome.