The invention provides an ultrasound imaging and medical instrument guiding apparatus, a system for acquiring and displaying ultrasound medical images and methods of using the apparatus and system in epidural anesthetic procedure. The apparatus comprises a hand-held ultrasound probe, configured to acquire a volumetric dataset representing a 3-D depiction of a volume a mount to which the probe is mounted and a medical instrument guide positionable relative to the ultrasound probe and configured to receive and guide a medical instrument along a propagation axis to a target in a body such that the target and the propagation axis intersect in the volume. The volumetric dataset acquired by the hand-held ultrasound probe comprises information about the medical instruments position relative to the target in three dimensions and the medical instrument guide has a visible mark from which the depth of the medical instrument insertion along the propagation axis can be referenced.
