Deltoid muscle volume estimated from ultrasonography: in vitro validation and correlation with isokinetic abduction strength of the shoulder.

Accurate prediction of muscle parameters can be used for customization of biomechanical models. A method is presented to estimate the volume of triangular-shaped muscles from ultrasonographic measurements. The deltoid muscle was used to validate the technique in a cadaver study of 12 shoulders. The relationship between isokinetic abduction strength and estimated deltoid muscle volume of the dominant shoulder of 30 healthy male subjects was analysed. Isokinetic joint moments were quantified using the Biodex System 3. A significant relationship (R = 0.87; p < 0.001) between the calculated deltoid volume and the isokinetic abduction peak torque was established.