A medical device-placing system, comprising: an ultrasound probe configured to emit ultrasound signals into a limb of a patient and receive echoed ultrasound signals from the patient's limb by way of a piezoelectric sensor array; an array of magnetic sensors embedded within a housing configured for placement about the patient's limb; a console having electronic circuitry including memory and a processor configured to: transform the echoed ultrasound signals to produce ultrasound-image segments corresponding to anatomical structures of the patient's limb, and transform magnetic-sensor signals from the array of magnetic sensors into location information for a magnetized medical device within the patient's limb when the housing is placed about the patient's limb; and an alternative-reality headset, including: a frame having electronic circuitry including memory and a processor; and a display screen coupled to the frame through which a wearer of the alternative-reality headset can see the patient's limb, the display screen configured to display over the patient's limb a virtual medical device in accordance with the location information for the medical device within objects of virtual anatomy corresponding to the ultrasound-image segments; wherein the console is configured to transform the ultrasound-image segments into the objects of virtual anatomy with a virtualization algorithm and send both the virtual medical device and the objects of virtual anatomy to the alternative-reality headset for display over the patient's limb. an ultrasound probe configured to emit ultrasound signals into a limb of a patient and receive echoed ultrasound signals from the patient's limb by way of a piezoelectric sensor array; an array of magnetic sensors embedded within a housing configured for placement about the patient's limb; a console having electronic circuitry including memory and a processor configured to: transform the echoed ultrasound signals to produce ultrasound-image segments corresponding to anatomical structures of the patient's limb, and transform magnetic-sensor signals from the array of magnetic sensors into location information for a magnetized medical device within the patient's limb when the housing is placed about the patient's limb; and transform the echoed ultrasound signals to produce ultrasound-image segments corresponding to anatomical structures of the patient's limb, and transform magnetic-sensor signals from the array of magnetic sensors into location information for a magnetized medical device within the patient's limb when the housing is placed about the patient's limb; and an alternative-reality headset, including: a frame having electronic circuitry including memory and a processor; and a display screen coupled to the frame through which a wearer of the alternative-reality headset can see the patient's limb, the display screen configured to display over the patient's limb a virtual medical device in accordance with the location information for the medical device within objects of virtual anatomy corresponding to the ultrasound-image segments; a frame having electronic circuitry including memory and a processor; and a display screen coupled to the frame through which a wearer of the alternative-reality headset can see the patient's limb, the display screen configured to display over the patient's limb a virtual medical device in accordance with the location information for the medical device within objects of virtual anatomy corresponding to the ultrasound-image segments; wherein the console is configured to transform the ultrasound-image segments into the objects of virtual anatomy with a virtualization algorithm and send both the virtual medical device and the objects of virtual anatomy to the alternative-reality headset for display over the patient's limb.