the following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention . the description is not to be taken in a limiting sense , but is made merely for the purpose of illustrating the general principles of the invention , since the scope of the invention is best defined by the appended claims . various inventive features are described below that can each be used independently of one another or in combination with other features . broadly , embodiments of the present invention generally provide a method and instrument for making surgical incisions through a tissue layer while holding underlying tissue away from an incision plane . referring to the figures various views are shown of an exemplary embodiment of a surgical knife 10 . the knife 10 may comprise a blade 18 with a blade cutting edge 20 and a handle 22 with handle grip ribs 24 , a logo area 26 , a blade recess 28 , a tissue - displacing member 30 and a concave arc - shaped notch 32 . the blade 18 may be a conventional scalpel blade that may have a curved or a straight cutting edge 20 . the blade 18 may be positioned in the arc - shaped notch 32 of the handle 22 . a portion of the cutting edge 20 may project below a lower surface 42 of the handle 22 . the tissue - displacing member 30 may have a convex arc shape . an outer tip 30 - 1 of the member 30 may have a smooth rounded shape with a radius of between about 1 . 5 mm to 3 mm . the outer tip 30 - 1 may project below a forward end 20 - 1 of the blade cutting edge 20 by a distance l . advantageously the distance l may be between about 1 mm to about 6 mm . the outer tip 30 - 1 may project a distance d below the bottom surface 42 of the handle 22 . advantageously , the distance d may be between about 7 mm to about 10 mm . the knife 10 may be constructed with the blade 18 imbedded in the handle 22 as an injection molded assembly . in that regard , the knife 10 may be produced as a relatively inexpensive and disposable surgical instrument . in operation , the knife 10 may be employed to safely make an incision in a tissue layer such as a peritoneum or dural layer without risk that the blade 18 may cause damage to underlying organs or tissue . referring particularly to fig7 , it may be seen that tip 30 - 1 of the knife 10 may be inserted through an initial - entry opening in the tissue layer or membrane 14 . the blade 20 may be then drawn across the membrane 14 to be cut . the tip 30 - 1 of the tissue - displacement member 30 may press against underlying tissue 15 to displace the tissue 15 from the incision plane . it may be seen that the knife 10 may safely make incisions while being either pulled or pushed along the incision plane . it should be understood , of course , that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims .
a surgical knife may include a handle and a blade embedded in the handle . the handle may have a tissue - displacing member surrounding the blade .