"15.0-24.0 MHz: superficial structures, musculoskeletal imaging"
"Higher ultrasound frequencies have shorter wavelengths and provide better detail and spatial resolution (recall that axial resolution (ultrasound) = ½ ⨉ spatial pulse length). However, shorter wavelengths are absorbed/attenuated more easily. Therefore, higher frequencies are not as penetrating. This explains why high frequencies are used for the superficial body structures and low frequencies are used for those that are deeper."
"2.5 MHz: deep abdomen, obstetric and gynaecological imaging"
"3.5 MHz: general abdomen, obstetric and gynaecological imaging"