Safety trocar assembly

A safety trocar assembly comprising:

• a trocar unit having an elongated obturator with a penetrating distal end;
• and
• a port unit with an elongated tubular cannula, having an open distal end through which said penetrating distal end of said obturator is exposed, wherein said obturator further comprises
• a penetrating means for orifice formation in a body cavity wall disposed onto said penetrating distal end, said penetrating means having at least two penetrating zones in the form of 1) a distal penetrating zone configured to initiate cavity wall penetration by forming an orifice in a body and firstly entering a body cavity through said orifice, and 2) a proximal penetrating zone configured to enlarge said orifice formed by said distal penetrating zone,
• a protector means, having at least a distal independent protector member and a proximal independent protector member for independent protection of each of said distal and proximal penetrating zones respectively during said cavity wall perforation, and
• a resilient bias means for each of said protector members, said bias means enabling said protector members to move independently of each other from an extended position to a retracted position in response to a resistance from perforated tissue encountered by said protector members, and to move independently of each other from said retracted position to said extended position when said resistance from perforated tissue is no longer encountered by said protector members after said penetrating zones have entered said body cavity.