Results of dissection of middle cranial fossa of the skull base of 50 white and no-white brazilian cadavers' whose ages varied form 25 to 80 years are reported. The anatomic relations of the ovale foramen emissary sinus with the surrounding dura mater and nervous components were systematized. It was verified that the lateral walls of the emissary sinus of the foramen ovale are related to: a) with the anterior edge of the trigeminal ganglion in the totality of the examined cases; b) with the middle third of the medial face of the trigeminal ganglion, in 68% of the examined cases; c) with the medial surface of the proximal extreme of the maxilar branch, in the totality of the examined cases; d) with the anterior superior edge and the anterior half of the medial surface of the intracranial segment of the mandibular nerve, including its motor root, in 99% of the examined cases; e) with the lateral face of the intracranial segment of the mandibular nerve, at the foramen ovale, in 9% of the examined cases; f) with the region between the inferior edge of the ophtalmic nerve and the superior edge of the maxilar nerve (angle V1-V2), near its vertex in 45% of the examined cases; g) with the region between the inferior edge of the maxilar nerve and the anterior edge of the mandibular nerve (angle V2-V3), in 100% of the examined cases. The author concludes that the quoted emissary sinus is an important anatomic element at the clinical-surgical point of view. It must be recalled mainly in concern with the surgical therapy of the trigeminal ganglion, and the maxillary and mandibular nerves intracranial segment.