Introduction: Firstly described in 1699 by Dupré, the muscle of knee joint (MAJ) is small and flat and consists of several muscular bundles that originate in the previous surface of the distal part of the femur and are inserted in the proximal part of the synovial membrane of the articulation of the knee, and function in the retraction of the suprapatelar synovial bursa during the extension of the leg, avoiding that the pleats inside this articulation are pressed between the femur and the patella. The objective of the present study valued the morphological aspects as for the format, fixation, sense and proximal and distal position of the muscular bundles of the MAJ. Materials and methods: Five knees of human corpses (being two left and three right ones, previously fixed with formaldehyde to 10% and glycerin) of both genders of the Institute of Anatomy of the University Severino Sombra were analyzed. An average (size,value,etc.) was calculated and obtained through the length and width of the MAJ through the use of a caliper ruler of polyethylene. Results: The total length of the MAJ varied from five to eleven cm (medium = 8,3 cm). Three anatomic presented morphology of the trapezoidal type, one presented morphology of the rectangular type and another presented morphology not found in the classification of Didio (2002). Conclusion: Our study established the presence of this muscle as a different muscular structure from the quadriceps femoral muscle, observing a morphological type not described in the literature.