- Definition: minimum distinguishing distance of two objects parallel
to sound wave travelling - Units: mm, cm
- Determined by the Spatial pulse length. Axial resolution=SPL/2
- Not adjustable by sonographer
- Typical value in clinical setting range from 0.1 to 1 mm
- Axial resolution is increased when wavelength, cycles in a pulse and
pulse duration are decreased. Axial resolution is increased when
frequency is increased