Increased Scapular Anterior Tilting and Decreased Humeral Internal Rotation in the Mouse Shoulder in Computer Workers with Shoulder Pain Jeon In-cheol1, Kwon Oh-Yun2,*, Hwang Ui-Jae3, Jung Sung-Hoon3, Weon Jong-Hyuck4 1Department of Physical Therapy, College of Life & Health Sciences, Hoseo University, Republic of Korea 2Department of Physical Therapy, College of Health Science, Yonsei University, South Korea 3Department of Physical Therapy, Graduate School, Yonsei University, Wonju, South Korea 4Department of Physical Therapy, College of Tourism & Health Science, Joongbu University, South Korea *Corresponding Author: Oh-yun Kwon, Department of Physical Therapy, College of Health Science, Yonsei University, South Korea, Email: kwonoy@yonsei.ac.kr
Online published on 30 April, 2019. Abstract The purpose of this study was to investigate whether the pectoralis minor on the mouse shoulder side and that on the non-mouse shoulder side were significantly different in length, resulting in a different angle of shoulder internal rotation. This study included 33 computer workers employed in an electronics company who engaged in heavy mouse use (> 6.1 h/day). The distance between the chair backrest and the posterior aspect of the lateral acromion process in the transverse plane during working was measured by two-dimensional photographic analysis (acromion distance). The length of the pectoralis minor was determined using a ruler to measure the distance between the examining table and the posterior aspect of the lateral acromion process in a supine position. Internal and external rotation of the mouse and non-mouse shoulders was measured using a universal goniometer. In the mouse shoulder, the acromion was in a 53.7% more anterior position in the transverse plane compared with the non-mouse shoulder during working. The distance of pectoralis minor differed by 39.7% between the mouse and non-mouse shoulder (p < 0.001). The mouse shoulder showed more limited passive internal rotation (69.2% of the normal range) with pain (VAS 5.2) compared with the non-mouse shoulder (79.0% of normal range) without pain. This suggests that excessive and frequent anterior tilting of the scapula in the mouse shoulder may compensate for shoulder internal rotation, leading to inhibition of shoulder internal rotation during working compared with the non-mouse shoulder. Top Keywords Computer workers, Humeral internal rotation, Mouse shoulder, Scapular anterior tilting. Top |