Ultrasound imaging of the serratus anterior muscle at rest and during contraction

Abstract

The purpose of this study is to describe a clinically feasible method for measuring the thickness of the serratus anterior (SA) muscle using rehabilitative ultrasound imaging (RUSI) and to determine the reliability of repeated measures of that method. An exploratory clinical measurement study using a test-retest methodology was utilized to determine the reliability of the measurements in a sample of 20 healthy subjects. While sitting with the arm flexed 120°, the SA of each subject was imaged at rest, during an active hold and while holding a three pound weight. On Day 1, images were repeated three times for each condition by the same examiner. On Day 2, Examiner 1 and Examiner 2 repeated the scans. Images were examined offline by Examiner 1 with SA thickness measured superior to the most distal rib in the image. Reliability was evaluated using intraclass correlation coefficients (ICCs) and Bland-Altman plots. The intra-examiner reliability (same day) during rest, active hold and active hold with resistance was ICC3,3 = 0·892; ICC3,3 = 0·951; and ICC3,3 = 0·869-0·971, respectively. Intra-examiner reliability between days ranged from ICC3,2 = 0·613 at rest to ICC3,2 = 0·736 during active hold with resistance. Interexaminer reliability was moderate during active hold (ICC2,2 = 0·526) and active hold with resistance (ICC2,2 = 0·535) and poor during rest (ICC2,2 = 0·425). This study demonstrates that SA thickness can be measured reliably using RUSI by the same examiner and suggests that active movements may increase that reliability.

Assessment of the reliability of real time ultrasound scanning to measure the humeral head position in a number of glenohumeral joint positions

“…However, one of the limitations of palpation and mobilization techniques is that they may not provide quantified objective measurements of the shoulder [2]. There are now increasing moves towards the use of real time ultrasound scanning [RTUS] for investigating shoulder pathology due to its ability to provide a dynamic examination with high diagnostic accuracy [3] and the fact that it offers a potential method to visualize muscle contraction during examination and treatment [4].…”

Effect of Exercise Position on Percent Changes in Serratus Anterior Muscle Thickness

“…Unlike other assessment tools, Ultrasound Imaging (UI) provides isolated real time visualization of muscle contraction, thus allowing researchers and clinicians quick interpretation of the contraction of a specific muscle [9,10]. UI has been shown to be a valid and reliable assessment tool for measuring thickness and cross sectional areas of the transversus abdominus, obliques [11] A few studies have investigated muscle thickness measures of the SA in both healthy [16][17][18] and pathological populations [19]. In general, between and within day intra-rater reliability measuring SA thickness has been shown to be good to excellent in health individuals positioned in glenohumeral scaption [16,17].…”

“…In general, between and within day intra-rater reliability measuring SA thickness has been shown to be good to excellent in health individuals positioned in glenohumeral scaption [16,17]. Only one study has investigated inter rater reliability of SA thickness and the results were modest to poor [17].…”

“…UI has been shown to be a valid and reliable assessment tool for measuring thickness and cross sectional areas of the transversus abdominus, obliques [11] A few studies have investigated muscle thickness measures of the SA in both healthy [16][17][18] and pathological populations [19]. In general, between and within day intra-rater reliability measuring SA thickness has been shown to be good to excellent in health individuals positioned in glenohumeral scaption [16,17]. Only one study has investigated inter rater reliability of SA thickness and the results were modest to poor [17].…”

“…In general, between and within day intra-rater reliability measuring SA thickness has been shown to be good to excellent in health individuals positioned in glenohumeral scaption [16,17]. Only one study has investigated inter rater reliability of SA thickness and the results were modest to poor [17].Other studies have investigated the ability to detect changes in SA thickness using UI. Two studies found no differences in healthy individuals when adding various loads to the UE in scaption at both 90 degrees [16], and 120 degrees of elevation [18].…”