Endosseous Screw for Attaching a Plate to a Bone Site, Orthopedic Fracture Osteosynthesis Device and System for Fixing and Extracting an Endosseous Screw The present invention relates to an orthopedic fracture osteosynthesis device of the type comprising a plate and screws endosseous to fix it to a bony site. the endosseous screw (1) for securing a plate (102) to a bone site (300) comprising an at least partially threaded shaft (2), insertion means for inserting the screw into the bone site (300) and a distal portion ( 33) provided for engaging the plate (102) to secure it to the bone site (300) and comprising a head (3) having facets (30) defining an external peripheral profile provided for engagement with a tubular manipulation wrench ( 101) to allow the screw (1) to be extracted from the bone site (300) into which it was inserted, with the facets (30) being curvilinear and the external peripheral profile defined by the same facets (30) having a similar shape. to a convex barrel in order to allow a stable coupling between the tubular manipulation wrench (101) and the profile which is maintained during the screw loosening phase from the plate even when the tubular manipulation wrench ( 101) is oriented in an inc with respect to the longitudinal axis (x) of the endosseous screw (1), the facets (30) being even in number and defining a regular polygonal section along an average section (aa) of the head (3), with the middle section (aa) being an average cross section positioned in a plane perpendicular to the longitudinal axis of the screw and dividing each facet (30) into two inner and outer portions (30a, 30b), respectively, which mirror each other.parafuso endósseo para fixar uma placa a um sítio ósseo, dispositivo ortopédico para a osteossíntese de fraturas e sistema para fixar e extrair um parafuso endósseo a presente invenção se refere a um dispositivo ortopédico para a osteossíntese de fraturas, do tipo que compreende uma placa e parafusos endósseos para fixar o
