Identifying target anatomic locations in a subject's body, and delivering medicinal substances thereto, following transtissual progression (penetrating, cutting through body tissue) and reaching body tissue with medical device distal tip. Involves acquiring mechanical properties of body tissue. Exemplary medicinal substance is, or includes, a drug (anesthetic agent), and exemplary target anatomic location is epidural space in subject's body. Exemplary system includes: cannular member enclosing cannula lumen； pusher-probe having distal end in cannula lumen and positionable from retracted to protruding positions, wherein pusher-probe distal end protrudes out of cannula distal end； and extending mechanism including cam member, a follower shiftable from first to second stations on cam member, and plunger selectively traveling in cannula lumen while forcing relative motion between cam member and follower, wherein pusher-probe distal end repositions between retracted and protruding positions. Optionally, includes data-information analyzing device having triggering mechanism via a winged hub member and associated components.
