Figure 1.

Illustration of the reference lines used to measure the thickness of the deltoid muscle and length of the bony landmark. The line connecting the OP and DP was equally divided into 8 equal sections. The average value of each section was about 2 cm. AP: the anterior point of the acromion; PP: the posterior point of the acromion; OP: the origin point of the reference line; blue line: thickness measurement point of the deltoid muscle; x-axis: line connecting the AP and PP; DP: the lowest point of the deltoid tuberosity; y-axis: line connecting the OP and DP.