The present invention concerns a trocar comprising a body (13, 14, 15, 25, 26), coupled to a hollow cylindrical cannula (29) in which a n obturator (23) is insertable, and a top cap (10), having a top, that is capable to be removably coupled to ® the body (13,14,15), characterised in that the top cap (10) has p Ian inscribable in to a circle of radius R1, wherein a first section of the top cap (10) with a first plane passing through the top has a first upper contour comprising a central portion having a radius R2 of curvature not lower than the radius R1 of the circle into which the plan of the top cap (10) is inscribable, and wherein a second section of the top cap (10) with a second plane orthogonal to the first one and passing through the top has a second upper contour comprising a rear portion (72) having a radius R4 of curvature larger than the radius R1 of the circle into which the plan of the top cap (10) is inscribable.
