A surgical instrument for penetrating bodily tissue including an imaging element providing the capability for simultaneous visualization during penetration is disclosed. A transparent portion of the imaging element extends from the distal end of an elongated, substantially hollow shaft. The imaging element is shaped to enlarge an opening as the instrument is advanced into bodily tissue, and an endoscope can be inserted through the shaft adjacent the imaging element to visualize the penetration of tissue as the instrument is advanced. The imaging element may be substantially hollow, and have an annular interior region inside the shaft distal end. The endoscope can then be positioned to rest on the annular region to prevent glare from the reflection of light traveling from the endoscope to the window surface. The imaging element may also have a blade for facilitating the advance of the instrument through tissue. The blade not only has a sharp, linear cutting edge, but also a blunt edge for preventing inadvertent cutting of tissue. The blunt edge is preferably located near the tip and base of the imaging element. Additionally, the imaging element is generally conical and the penetrating surface has a region extending at an obtuse angle relative to the exterior surface of the conical element, and a second region extending generally parallel to the exterior surface of the conical element.