Fig. 1
From: Assessment of quadriceps muscle mass by ultrasound in the postoperative period of cardiac surgery
Assessment of quantitative and qualitative measurements of the quadriceps using ultrasound. A Measurement of the midpoint and distal third of the quadriceps, skin marking for sequential measurements, and muscle evaluation in the transverse axis with a high-frequency linear transducer. B Cross-sectional area of the rectus femoris. C Thickness of the rectus femoris and vastus internus. D Pennation angle of the rectus femoris. E Thickness and pennation angle of the vastus lateralis. F Length of the fascicle of the vastus lateralis using a linear extrapolation technique