One hundred mandibles of adult Chinese cadavers of both sexes without missing teeth, alveolar bone resorption and malposition of teeth were studied. The anatomical location of each mandibular mental foramen was measured by using a combination of three previous methods. Our results showed that the location of the mental foramen below the apex of the lower second premolar (relation IV: 58.98%) was the most common. On average, the distance between the most anterior portion of the anterior border of the mental foramen and the mandibular symphysis was 28.06 mm, between the most anterior portion of the anterior border of the mental foramen and the posterior border of the ramus 74.14 mm, between the inferior border of the mental foramen and the lower border of the mandibular body 14.70 mm, between the superior border of the mental foramen and the bottom of the lower second premolar socket 2.50 mm. The distance across the mental foramen between the alveolar crest and the lower border of the mandibular body was 30.29 mm. Our results were compared with those of other investigators. The significance of identifying the anatomical location of the mental foramen in dental practice is discussed.

One hundred dry skulls of adult Chinese of both sexes were studied. They were homogeneous in the form of maxillary arch and having full eruption of the upper third molar, without missing teeth and malposition of teeth. Our findings revealed that the mean distance from the center of the greater palatine foramen (GPF) to the midsagittal plane of the hard palate was 16.00 mm, and to the posterior border of the hard palate, 4.11 mm. The location of the GPF related to the maxillary molars was expressed as percentage in 5 relations. We found that the most common location of the GPF was between the maxillary second and third molars (relation III: 48%) and less common was lingual to the maxillary third molar (relation IV: 33.5%). The usually accepted description of the GPF location was lingual to the second molar (relation II), but in our study this relative position occurred in only 17% of the skulls. The long axis of the greater palatine canal directing to the GPF in the oral cavity was found to be directed anteriorly in 181 openings (90.5%) of the 200 GPF, and only 19 openings (9.5%) directed vertically. The bilateral symmetry of GPF on both sides of each skull was remarkable. The discrepancy of our observations on the Chinese skulls from those on other ethnic groups was discussed. Our findings suggest, therefore, the existence of an ethnic variation and the necessity of a more accurate method of locating the GPF in clinical practice.

One hundred and twenty Chinese adults’ facial halves were selected for this study. The description of the mandibular ramus of the facial nerve was presented under 4 items: (1) the relationship with the lower border of the mandible, (2) the number of its rami, (3) the relationship with the retromandibular vein, the facial vein or the facial artery, and (4) its anastomoses with the buccal ramus and/or the cervical ramus. In these specimens, anterior to the facial artery, 90% of the mandibular rami ran above the lower border of the mandible, and 10% of the mandibular rami ran below the lower border of the mandible. Posterior to the facial artery, 67% of the mandibular rami ran above the lower border of the mandible, and 33% of the lowest mandibular rami passed in an arc with an average of 0.95 cm (the lowest point being 3 cm or less) below the lower border of the mandible. In 32% of the specimens the mandibular ramus had no branch and in 68% of the specimens, the mandibular ramus had two or more rami. There were 100% of the mandibular rami lying superficially to the retromandibular vein and the facial vein, while in 5% of the specimens, some other mandibular rami ran deeply to the facial vein. In 83 % of the specimens the mandibular rami lay only superficially to the facial artery and in only 2% deeply to the facial artery. The remaining 15% ran both deeply and superficially to the facial artery. There were 60% of the specimens in which the mandibular rami had one or more anastomoses with the buccal rami. In addition, in 12% of the facial halves, the mandibular rami had one anastomosis with the cervical ramus. However, only 4% of the mandibular rami had anastomosing branches with both the buccal and the cervical rami. The results of this study indicate that (1) it is recommended and safe to make an incision line at least 0.5 cm below the lower border of the mandible while doing surgeries such as radical neck dissection and open reduction for mandibular angle fracture anterior to the facial artery and 2 finger breadths or 3 cm below the lower border of the mandible while doing the same surgeries posterior to the facial artery, (2) most of the mandibular rami have two branches innervating the depressor muscles of the lip (3) the retromandibular vein can be used as a guide during approaching the mandibular ramus at the mandibular angle and (4) the anastomoses with the buccal and/or the cervical ramus may provide additional innervation to the depressor muscles of the lip. Therefore, our findings suggest the existence of an ethnic variation and the necessity of a more accurate method of approaching the mandibular ramus in clinical practice.