Morise Shuhei, Muraki Takayuki, Ishikawa Hiroaki, Izumi Shin-Ichi
Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, Sendai, Japan(∗).
Department of Physical Medicine and Rehabilitation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai 980-8575, Japan(†).
PM R. 2017 Sep;9(9):892-900. doi: 10.1016/j.pmrj.2017.01.006. Epub 2017 Feb 4.
Aging is a contributing factor to rotator cuff tears. Dysfunction of the scapular muscles can be a potential cause of rotator cuff tears. Although aging can contribute to dysfunction of the scapular muscles and subsequently result in rotator cuff tears, the effects of aging on scapular muscles are unclear.
To determine changes in sizes and electromyographic activities of the scapular muscles with age in asymptomatic subjects.
Cross-sectional study.
Fifty-four asymptomatic subjects without shoulder pain and dysfunction (18 male and 36 female) were recruited for this study. Subjects consisted of 19 people aged 20-39 years (young adult group, 27.2 ± 5.2 years), 17 people aged 40-59 years (middle age group, 49.9 ± 6.6 years), and 18 people aged 60-79 years (elderly group, 68.0 ± 7.1 years).
Using ultrasonography, we measured the muscle thickness of the trapezius (upper and lower portions), serratus anterior, and middle deltoid muscles during rest with the subject in a sitting position. Activities of the same muscles were measured with surface electromyography during shoulder elevation in the scapular plane up to 120°. The electromyographic data were analyzed at ranges 0°-30°, 30°-60°, and 60°-90°. Analysis of variance and Bonferroni multiple comparisons were used for statistical analysis.
Muscle thickness of the lower trapezius in the elderly group was decreased significantly compared with that in the young adult group (95% confidence interval -0.40, 2.24; P < .001) and middle age group (95% confidence interval -0.34, 1.89; P = .012). There were no significant differences in muscle activity and activity ratio between groups.
In scapular muscles, muscle thickness of the lower trapezius significantly decreased with aging, although there were no decreases in muscle thicknesses of the other muscles between different age groups. For the functional change, aging may not affect the scapular muscle activities and balance of the activities between the deltoid and scapular muscles.
IV.
衰老为肩袖撕裂的一个促成因素。肩胛肌功能障碍可能是肩袖撕裂的潜在原因。尽管衰老可导致肩胛肌功能障碍并继而引发肩袖撕裂，但衰老对肩胛肌的影响尚不清楚。
确定无症状受试者肩胛肌大小及肌电图活动随年龄的变化。
横断面研究。
本研究纳入54例无肩部疼痛及功能障碍的无症状受试者（18例男性和36例女性）。受试者包括19例年龄在20 - 39岁的人群（青年组，27.2±5.2岁）、17例年龄在40 - 59岁的人群（中年组，49.9±6.6岁）以及18例年龄在60 - 79岁的人群（老年组，68.0±7.1岁）。
采用超声检查，让受试者坐位休息时测量斜方肌（上部和下部）、前锯肌及三角肌中部的肌肉厚度。在肩胛平面将肩部抬高至120°的过程中，用表面肌电图测量相同肌肉的活动。肌电图数据在0° - 30°、30° - 60°和60° - 90°范围内进行分析。采用方差分析和Bonferroni多重比较进行统计学分析。
老年组斜方肌下部的肌肉厚度与青年组（95%置信区间 - 0.40, 2.24；P <.001）和中年组（95%置信区间 - 0.34, 1.89；P =.012）相比显著降低。各组之间的肌肉活动及活动比率无显著差异。
在肩胛肌中，斜方肌下部的肌肉厚度随衰老显著降低，尽管不同年龄组之间其他肌肉的厚度没有降低。对于功能变化，衰老可能不会影响肩胛肌活动以及三角肌与肩胛肌之间活动的平衡。
IV级。
