Depth of target/landmark (cm) on US (d US) | Angle (α°) between US probe and needle | ||||||||||||
15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 75 | |
1 | 1 | 1.1 | 1.1 | 1.2 | 1.2 | 1.3 | 1.4 | 1.6 | 1.7 | 2 | 2.4 | 2.9 | 3.9 |
1.5 | 1.6 | 1.6 | 1.7 | 1.7 | 1.8 | 2 | 2.1 | 2.3 | 2.6 | 3 | 3.5 | 4.4 | 5.8 |
2 | 2.1 | 2.1 | 2.2 | 2.3 | 2.4 | 2.6 | 2.8 | 3.1 | 3.5 | 4 | 4.7 | 5.8 | 7.7 |
2.5 | 2.6 | 2.7 | 2.8 | 2.9 | 3 | 3.3 | 3.5 | 3.9 | 4.4 | 5 | 5.9 | 7.3 | 9.6 |
3 | 3.1 | 3.2 | 3.3 | 3.5 | 3.7 | 3.9 | 4.2 | 4.7 | 5.2 | 6 | 7.1 | 8.8 | 11.6 |
3.5 | 3.5 | 3.7 | 3.9 | 4 | 4.3 | 4.6 | 4.9 | 5.4 | 6.1 | 7 | 8.3 | 10.2 | 13.5 |
4 | 4.1 | 4.3 | 4.4 | 4.6 | 4.9 | 5.2 | 5.7 | 6.2 | 7 | 8 | 9.5 | 11.7 | 15.5 |
4.5 | 4.7 | 4.8 | 5 | 5.2 | 5.5 | 5.9 | 6.4 | 7 | 7.8 | 9 | 10.6 | 13.2 | 17.4 |
5 | 5.2 | 5.3 | 5.5 | 5.8 | 6.1 | 6.5 | 7.1 | 7.8 | 8.7 | 10 | 11.8 | 14.6 | 19.3 |
d N=d US sec(α).