Morphological Studies on the Mandible of Indians: The Incisura Foraminis Mandibulae and Canalis Mylohyoideus

DOI
  • FURUTA YOSHIKO
    Third Department of Anatomy, Nippon Dental University, Fujimi-cho, Chiyoda-ku, Tokyo, Japan

抄録

The lower edge of the Foramen mandibulae shows various degrees of depth of indentation forming the Incisura foraminis mandibulae. The degree of formation of the Incisura markedly influences the morphology of the Foramen mandibulae, being intimately related with the level of branching of the Nervus mylohyoideus. Compared to the intense interest in the confirmation of the position and morphology of the Foramen mandibulae as the site of anesthetic transmis sion, there are extremely few reports available on the Incisura foraminis mandibulae, other than that by the author on the Japanese. There are no detailed reports available on the Canalis mylohyoideus in relation to the degree of for mation of the Incisura foraminis mandibulae.<BR>Using 356 sides of 178 Indian mandibles, the sexual dimorphism which could not be investigated in the Japanese materials, the degree of protrusion of the Lingula mandibulae and the position of the Sulcus with reference to the Foramen mandibulae, were supplementarily studied. The presence or absence of racial differences was assessed by comparison with the author's results for the Japanese.<BR>I. Incisura foraminis mandibulae<BR>A. The degree of formation of the Incisura was investigated according to a four-type classification.<BR>The total of Type I with a shallow Incisura and Type II with a moderately deep Incisura, both of which are considered to be normal, amounted to approximately 60% of males and approximately 84.5% of females. The incidences of Type III with a deep Incisura and Type IV without an Incisura, both of which are considered to represent a transition from normal, were much higher in males than in females. Comparison of the Indians with Japanese revealed that a moderately deep Incisura was found in about 1/2 of the Indians while a shallow Incisura was seen about 1/2 of the Japanese.<BR>B. Individuals having the same type of Incisura on the right and left sides amounted to approximately 57.0% of the Indians and approximately 77.0% of the Japanese, so that there was a higher incidence of right-left symmetry in Japanese than in Indians.<BR>C. The relationship between the grading of the degree of protrusion of the Lingula mandibulae classified into 5 types and the type of Incisura was analyzed. Type 3 with a relatively distinct protrusion of the Lingula mandibulae was frequently found in association with a moderately deep Incisura of Type II. The incidence of Type 1 with a marked protrusion was high in Type III with a deep Incisura.<BR>II. A Canalis mylohyoideus was formed in 4.2±1.1% in the present study. A similar incidence is also indicated by the results of other investigatigators on the Japanese. A. Sexual dimorphism. The Canalis mylohyoideus was formed in 5 of 82sides of male specimens (6.1±2.6%) and 5 of 122 sides of females specimens (4.1±1.8%). Males thus showed a higher incidence. B. Canalis formation in combination with Types I and IV was mostly found, except for 2 specimens of Type III with a deep Incisura. Among Japanese specimens, Type IV was always found. Among Indians, strange shapes were frequently noted. C. One unusual aspect of the morphology of specimens of Type III, was that the Sulcus nervi mylohyoideus was located markedly lateral to the Foramen mandibulae. D. Formation of this Canalis was intimately related with the branching of the Nervus mylohyoideus at a deeper site and complete block of this nerve.

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詳細情報 詳細情報について

  • CRID
    1390282680438018816
  • NII論文ID
    130004650088
  • DOI
    10.2535/ofaj1936.58.4-6_1073
  • COI
    1:STN:280:DyaL3s%2FhtlOrsw%3D%3D
  • ISSN
    0030154X
  • 本文言語コード
    en
  • データソース種別
    • JaLC
    • Crossref
    • CiNii Articles
  • 抄録ライセンスフラグ
    使用不可

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