Department of Biomedical Engineering and Chemical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA; Graduate School of Health Sciences, Yamagata Prefectural University of Health Sciences, Yamagata, Japan.
Department of Biomedical Engineering and Chemical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA.
Clin Biomech (Bristol). 2021 May;85:105328. doi: 10.1016/j.clinbiomech.2021.105328. Epub 2021 Mar 19.
A better understanding of the morphological and functional differences in the anatomical sub-regions of the rotator cuff muscles is critical so that appropriate surgical and rehabilitation methodologies can be implemented in patients with shoulder-related injuries. The purpose of the current study was to develop a comprehensive imaging protocol using shear-wave elastography for the infraspinatus and teres minor muscles, and investigate differences in elastic properties of three distinct infraspinatus muscle sub-regions and of the teres minor muscle.
First, we developed a protocol for probe positioning for both muscles using three cadaveric shoulders. Second, we evaluated in-vivo elastic properties [passive and active stiffness (kPa)] and excursion (mm) outcomes from these muscles during shoulder external rotation.
Elastic properties were significantly different among the infraspinatus muscle sub-regions and teres minor muscle. Passive stiffness decreased with increasing rotation angles except for the middle sub-region of the infraspinatus muscle which showed a decreased up to mid-range followed by an increment towards the end-range. Overall, active stiffness of the infraspinatus muscle and teres minor muscle decreased with increasing rotation angles, while that of the middle sub-region increased up to mid-range, and decreased at the end-range.
Distinct characteristics of the infraspinatus and teres minor muscles, and more importantly, of the individual sub-regions within the infraspinatus muscle call for an in-depth analysis of their morphological and functional differences. Special attention should be put into these sub-regions when performing surgical and rehabilitation procedures for patients with shoulder-related injuries.
深入了解肩袖肌肉解剖亚区的形态和功能差异至关重要，以便为肩部相关损伤的患者实施适当的手术和康复方法。本研究的目的是开发一种使用剪切波弹性成像的综合成像方案，用于评估冈下肌和小圆肌，并研究三个不同冈下肌亚区和小圆肌的弹性特性差异。
首先，我们使用三个尸体肩部开发了用于这两块肌肉的探头定位方案。其次，我们评估了在肩部外旋过程中这些肌肉的弹性特性[被动和主动刚度（kPa）]和位移（mm）结果。
冈下肌亚区和小圆肌之间的弹性特性存在显著差异。除冈下肌中部亚区外，随着旋转角度的增加，被动刚度逐渐减小，冈下肌中部亚区在中程范围内减小，然后在末程范围内增加。总的来说，冈下肌和小圆肌的主动刚度随着旋转角度的增加而减小，而冈下肌中部亚区的主动刚度在中程范围内增加，在末程范围内减小。
冈下肌和小圆肌的特性，更重要的是冈下肌的各个亚区的特性，要求对其形态和功能差异进行深入分析。在对肩部相关损伤的患者进行手术和康复治疗时，应特别注意这些亚区。
