Figure 4From: Ultrasound evaluation in combination with finger extension force measurements of the forearm musculus extensor digitorum communis in healthy subjects Muscle pennation angle. (A) The black rectangle shows the position of the US probe during pennation angle measurements. (B) The longitudinal US image showing the superficial aponeurosis (black arrows), the deep aponeurosis (white arrows) and the pennation angle (α).Back to article page