The Angles of the Mandible in Korean - Three Dimensional Reconstruction Study / 체질인류학회지

The aim of this study was to analyze the difference of the measurements of mandible between young male and female using three dimensional reconstruction images derived from the facial bone CT images. Type classification of mandible was performed based on the angle of base of mandible and the angle of mandibular margin observed from the anterior view and the correlation among the measurement items was analyzed. One hundred-ninety five young adults facial CT were collected from the Konkuk University medical center (98 females, 97 males; mean age 25.9 years, range 18~38 years). Three dimensional images of the face were reconstructed using software from CT images of whole specimens. The angle of the base of the mandible, the angle of the mandibular margin, total length of mandibualr margin, and the height of mandibular symphysis were measured. All measurement items were larger and longer in male than female (P<0.05). Three types were classified according to the mandibular angle. In female, the subjects were evenly distributed among groups, but group I which had large mandibular angle was most common in male. The smaller the height of mandibular symphysis, the larger the angle of base of mandible or the angle of mandibular margin (P<0.05).

A Variation of the Musculocutaneous Nerve Absent

A variation of the brachial plexus, characterized by the absence of the musculocutaneous nerve on the left arm, was found during the dissection of a 28-year old male cadaver. The whole lateral cord was joined to the median nerve, which it met in two points. One was a typical junction of both roots of the median nerve at the level of the coracoid process. The other was a junction of the remaining lateral cord and the median nerve, which was 92 mm away from the typical junction. This case provided some evidence about the absence of the musculocutaneous nerve, rather than a complete fusion of the median and musculocutaneous nerves. As the nerves are named due to their course or innervation, and not from their origin, it is reasonable to assume that the combined nerve was actually the median nerve, and that the musculocutaneous nerve did not exist.

A Variation of the Musculocutaneous Nerve Absent

A variation of the brachial plexus, characterized by the absence of the musculocutaneous nerve on the left arm, was found during the dissection of a 28-year old male cadaver. The whole lateral cord was joined to the median nerve, which it met in two points. One was a typical junction of both roots of the median nerve at the level of the coracoid process. The other was a junction of the remaining lateral cord and the median nerve, which was 92 mm away from the typical junction. This case provided some evidence about the absence of the musculocutaneous nerve, rather than a complete fusion of the median and musculocutaneous nerves. As the nerves are named due to their course or innervation, and not from their origin, it is reasonable to assume that the combined nerve was actually the median nerve, and that the musculocutaneous nerve did not exist.