Rodríguez Vázquez, José Francisco

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First Name
José Francisco
Last Name
Rodríguez Vázquez
Universidad Complutense de Madrid
Faculty / Institute
Anatomía y Embriología
Anatomía y Embriología Humana
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Now showing 1 - 6 of 6
  • Publication
    Origin of the torus mandibularis: an embryological hypothesis
    (Wiley, 2013-11) Rodríguez Vázquez, José Francisco; Sakiyama, Koji; Verdugo López, Samuel; Amano, Osamu; Murakami, Gen; Abe, Shinichi
    Torus mandibularis, a well-known protuberance in the dental field, has been defined as a hyperostosis in the lingual aspect of the body of the mandible above the mylohyoid line. However, the origin of the torus mandibularis has not yet been clarified. The aim of this study was to provide a better understanding on the origin of the torus in view of the specific development of Meckel's cartilage at the site corresponding to the adult torus. A total of 40 mid-term human fetuses at 7-16 weeks of gestation were examined. The 10-13 weeks stage corresponded to the critical period in which Meckel's cartilage with endochondral ossification underwent a bending at the beginning of the intramandibular course. At the level of mental foramen, which was located between the deciduous canine and the first deciduous molar germs, the medial lamina of the mandible protruded medially to reach Meckel's cartilage. Thus, the medial lamina covered the posterior and superior aspect of the bending Meckel's cartilage just above the attachment of the developing mylohyoid muscle (i.e., in the oral cavity). We considered a bony prominence, which composed the protruding medial lamina and the bending Meckel's cartilage as the fetal origin of the torus mandibularis. A new theory is proposed for the origin of the torus mandibularis based on the existence of an anlage formed during the development of the mandible, variable in morphology and size, but always constant.
  • Publication
    Development of the stapedius muscle and unilateral agenesia of the tendon of the stapedius muscle in a human fetus
    (Wiley, 2010-01) Rodríguez Vázquez, José Francisco; Mérida Velasco, José Ramón; Verdugo López, Samuel
    The objective was to analyze the development of the stapedius muscle to understand an isolated unilateral absence of the tendon of the stapedius muscle in a human fetus. The study was made on 50 human embryos and fetuses aged 38 days to 17 weeks post-conception. The stapedius muscle was formed by two anlagen, one for the tendon, which derives from the internal segment of the interhyale and another for the belly, located in the second pharyngeal arch, medially to the facial nerve and near the interhyale. In the interhyale, two segments were observed forming an angle and delimited by the attachment of the belly of the stapedius muscle. The internal segment will form the tendon. The lateral segment of the interhyale was attached to the cranial end of the Reichert's cartilage (laterohyale), and normally it disappears at the beginning of the fetal period. The right unilateral agenesia of the tendon of the stapedius muscle, observed for the first time in a human fetus of 14 weeks post-conception development (PCd), was brought about by the lack of formation or the regression of the internal segment of the interhyale. It presented a belly of the stapedius muscle with an anomalous arrangement, and with a pseudo tendon originated by the persistence of the external segment of the interhyale.
  • Publication
    Fetal topographical anatomy of the female urethra and descending vagina: a histological study of the early human fetal urethra
    (Elsevier, 2011-12) Masumoto, Hiroshi; Rodríguez Vázquez, José Francisco; Verdugo López, Samuel; Murakami, Gen; Matsubara, Akio
    Background: Which parts of the male urethra correspond to the female urethra? To resolve this question, we need to understand fetal topographical changes in the urethra, its external sphincter and vagina. The vagina joins the mid-course of the primitive urethra and, later "descends" to the vaginal vestibulum. Methods: We examined histological sections of 14 female and 4 male mid-term fetuses. Results: The inferior end of the vagina was consistently embedded in the posterior wall of the urethra at 9-12 weeks. The supero-inferior level of the vaginal merging was lower in larger fetuses. Thus, the sequential variation in levels appeared to reflect the process of vaginal descent. However, in spite of penetration of the vaginal end into the posterior urethral wall, we found no sign of destruction of the urethral wall after vaginal descent in the low-merging types. Before vaginal descent, the female external sphincter extended posterolaterally around the urethra. Conclusion: The vaginal descent is classically regarded as a relative topographical change, but it is likely to be a result of elongation of the proximal urethra in the superior side of the vaginal merging. Conversely, the distal urethra is likely to be incorporated into the vaginal vestibulum by 15 weeks. During these processes, most of the female external sphincter seems to be expelled from the original anterior position into the vestibular wall as the urethrovaginal sphincter. The adult female urethra seems to correspond to the male prostatic urethra superior to the prostatic colliculus.
  • Publication
    Initial stage of fetal development of the pharyngotympanic tube cartilage with special reference to muscle attachments to the tube
    (ACB, 2012-09) Katori, Yukio; Rodríguez Vázquez, José Francisco; Verdugo López, Samuel; Murakami, Gen; Kawase, Tetsuaki; Kobayashi, Toshimitsu
    Fetal development of the cartilage of the pharyngotympanic tube (PTT) is characterized by its late start. We examined semiserial histological sections of 20 human fetuses at 14-18 weeks of gestation. As controls, we also observed sections of 5 large fetuses at around 30 weeks. At and around 14 weeks, the tubal cartilage first appeared in the posterior side of the pharyngeal opening of the PTT. The levator veli palatini muscle used a mucosal fold containing the initial cartilage for its downward path to the palate. Moreover, the cartilage is a limited hard attachment for the muscle. Therefore, the PTT and its cartilage seemed to play a critical role in early development of levator veli muscle. In contrast, the cartilage developed so that it extended laterally, along a fascia-like structure that connected with the tensor tympani muscle. This muscle appeared to exert mechanical stress on the initial cartilage. The internal carotid artery was exposed to a loose tissue facing the tubal cartilage. In large fetuses, this loose tissue was occupied by an inferior extension of the temporal bone to cover the artery. This later-developing anterior wall of the carotid canal provided the final bony origin of the levator veli palatini muscle. The tubal cartilage seemed to determine the anterior and inferior margins of the canal. Consequently, the tubal cartilage development seemed to be accelerated by a surrounding muscle, and conversely, the cartilage was likely to determine the other muscular and bony structures.
  • Publication
    Venous drainage from the developing human base of mandible including Meckel's cartilage: the so-called Serres' vein revisited
    (Springer, 2011-09) Rodríguez Vázquez, José Francisco; Verdugo López, Samuel; Murakami, Gen
    Purpose: The present study describes the venous drainage, especially, that via the so-called Serres' vein, from border areas between two different types of ossifications: the endochondral ossification of Meckel's cartilage in close topographical relation with the membranous ossification of the mandible. Methods: Frontal and transverse sections of 25 human fetuses between 8 and 16 weeks of post-conception development. All sections were stained with hematoxylin, and eosin and azan. Results: At 9 weeks, a distinct vein (Serres' vein) is seen originating from the endochondral ossification of Meckel's cartilage. At 11 weeks, the vein collects blood sinusoids from both the endochondral and membranous ossification areas. At 12 weeks the vein accompanies a definite bony canal, the Serres' canal. The vein does not extend anteriorly beyond a level of the deciduous canine germ that was located anterior to the mental foramen. Notably, up to 12 weeks, the vein becomes clearly isolated from the inferior alveolar nerve, artery, and vein. Conclusion: Serres' vein seems to be a unique drainage route of ossification, not of the tooth germ, and is similar to veins at the usual diaphysis of a long bone. Although the Serres' canal had been termed "canal of the deciduous dentition", there appears to be no topographical relation with deciduous germs.
  • Publication
    Embryonic anastomosis between hypoglossal nerves
    (Springer, 2009-12) Rodríguez Vázquez, José Francisco; Mérida Velasco, José Ramón; Verdugo López, Samuel; Sanz Casado, José Vicente; Jiménez Collado, Juan
    This article presents two cases of anastomosis of hypoglossal nerves in the suprahyoid region in human embryos of CR length 10.75 and 17.5 mm. This variation was studied in two human specimens at this stage of development and compared with the normal arrangement of the hypoglossal nerves in embryos at the same stage. The anastomotic branches were of similar caliber to the main trunks. In both cases the anastomosis was located dorsal to the origin of the geniohyoid muscles and caudal to the genioglossus muscles, lying transversally over the cranial face of the body of the hyoid bone anlage. The anastomosis formed a suprahyoid nerve chiasm on the midline in the embryo of 10.75 mm CR length.