Dexter William Witt

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

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.

Ultrasound examination of the serratus anterior during scapular protraction in asymptomatic individuals: reliability and changes with contraction.

OBJECTIVE To determine the ability of 2 clinicians to reliably measure the thickness of the serratus anterior (SA) muscle using ultrasound during scapular protraction and to determine whether that thickness changes during activation of the SA. DESIGN A cross-sectional observational study. SETTING An outpatient biomechanical laboratory. PARTICIPANTS Twenty healthy, asymptomatic adults between the ages of 23 and 28 years. METHODS Ultrasound imaging measurements were recorded during 3 conditions: (1) with the subject in a side-lying position and resting in a supported position of 90° of shoulder flexion; (2) with the subject in a side-lying position and the shoulder in 90° of shoulder flexion and actively protracting; and (3) with the subject in a side-lying position and the shoulder in 90° of shoulder flexion while holding the protracted position against 15 lb of force. MAIN OUTCOME MEASUREMENTS Reproducibility was examined with use of intraclass correlation coefficients (ICCs) and standard error of measurements. The thickness of the SA muscle measured during each condition was compared. RESULTS Intratester and intertester ICC values were high. Ranges for ICCs were 0.892-0.979 for intratester reliability within a session, 0.900-0.912 for intratester reliability between sessions, and 0.929-0.939 for intertester reliability. Statistically significant differences in the thickness of the SA were found between the rest condition and the hold with resistance condition but not between the rest condition and the active hold condition. CONCLUSION Findings of this study document the high reliability of ultrasound imaging in determining SA muscle thickness and thickness changes at rest and during contraction of the SA. Clinicians should be aware that resistance may need to be added to active scapular protraction in a side-lying position to produce a significant change in SA thickness from the rest position. This information can be used by clinicians who assess the SA and treat scapular dysfunction when activation or facilitation of the SA is required.

Ultrasonographic measurements of lower trapezius muscle thickness at rest and during isometric contraction: a reliability study

Abstract Objective: The purpose of this study was to determine the intra-rater reliability and inter-rater reliability of ultrasound imaging (USI) thickness measurements of the lower trapezius (LT) at rest and during active contractions when the transverse process and the lamina were used as reference sites for the measurement process. Participants: Twenty healthy individuals between the ages of 22 and 32 years volunteered. Methods: With the subject prone and the shoulder in 145° of abduction, images of the LT were taken bilaterally by one examiner as the subject: (1) rested; (2) actively held the test position; and (3) actively held the test position while holding a weight. Ten subjects returned and testing was repeated by the same examiner and by a second examiner. LT thickness measurements were recorded at the level of the transverse process and at the level of the lamina. Results: Intra-class correlation coefficients (ICC) for within session intra-rater reliability (ICC3,3) ranged from 0.951 to 0.986 for both measurement sites while between session intra-rater reliability (ICC3,2) ranged from 0.935 to 0.962. Within session inter-rater reliability (ICC2,2) ranged from 0.934 to 0.973. Conclusions: USI can be used to reliably measure LT thickness at rest, during active contraction and during active contraction when holding a weight. The described protocol can be utilized during shoulder examinations to provide an additional assessment tool for monitoring changes in LT thickness.

The effect of shoulder position on inferior glenohumeral mobilization

Study Design: Cross‐sectional clinical measurement study. Introduction: Inferior mobilizations are used to treat patients with shoulder dysfunctions. Common positions recommended for promoting an inferior glide include: (1) an open‐packed position (OPP) in which the shoulder is in 55° of abduction, 30° of horizontal adduction, and no rotation; (2) neutral position (NP) of the shoulder; and (3) position of 90° of shoulder abduction (ABDP). Studies comparing the impact of position on inferior mobilization are lacking. Purpose of the Study: To determine the effect of shoulder position on humeral movement and mobilization force during inferior mobilizations. Methods: Twenty‐three subjects were tested bilaterally. Subjects were placed in the OPP, and an ultrasound transducer placed over the superior glenohumeral joint. As inferior mobilization forces were applied through a dynamometer, ultrasound images were taken at rest and during 3 grades of inferior mobilization. This process was repeated in the NP and the ABDP. Results: In the NP, movements during grade 1, 2, and 3 mobilizations were 1.8, 3.8, and 4.5 mm, respectively. Movements measured in the OPP (1.0, 2.4, and 3.6 mm, respectively) and in the ABDP (1.0, 2.2, and 2.3 mm, respectively) were less. Forces were higher in the NP during grade 1, 2, and 3 mobilizations (51.8, 138.7, and 202.1 N, respectively) than in the OPP (37.2, 91.2, and 139.9 N, respectively) and the ABPD (42.5, 115.3, and 165.5 N, respectively). Discussion: Mobilization position altered the movement and force during inferior mobilizations. Conclusions: Shoulder position should be considered when utilizing inferior mobilizations. Level of Evidence: NA.