Symmetry of anterior tibial muscle size measured by real-time ultrasound imaging in young females

Abstract

The between-limb symmetry of anterior tibial muscle size was examined in 40 healthy females, aged 18-35 years (20.7 ± 3.9). Real-time ultrasound imaging was used to measure the cross-sectional area (CSA) of the muscle group. With the subject half-lying, bilateral scans were taken and measurements of CSA were made by tracing the muscle group outline using an onscreen electronic calliper. On each scan, two CSA measurements were made and the mean of the two measurements was used in the analysis. Between-side comparisons were made by expressing the CSA of the smaller muscle as a percentage of that of the larger muscle and the mean, standard deviation and range for the 40 subjects were calculated. The paired t-test was used to compare the raw data between-sides, i.e. larger versus smaller muscle. The smaller muscle was approximately 93% of the size of the larger muscle with a mean difference of 7.2% ± 5% and a range of 0.1-20%. The differences between the raw values for CSA were significantly different (p < 0.001). The degree of symmetry of anterior tibial muscle size has been documented in a group of normal young females using real-time ultrasound scanning, which could be used to examine wasting in patients with unilateral leg injuries or pathology. The degree of normal symmetry for other subject groups of both sexes and different ages needs to be documented.