Anatomy of the lingual nerve: Application to oral surgery.

The purpose of this research is to obtain morphological information about the traveling route, branching pattern, and distribution within the tongue of the lingual nerve, all of which are important for oral surgical procedures. Using 20 sides from 10 Japanese cadaveric heads, we followed the lingual nerve from its merging point with the chorda tympani to its peripheral terminal in the tongue. We focused on the collateral branches in the area before reaching the tongue and the communication between the lingual and hypoglossal nerves reaching the tongue. The collateral branches of the lingual nerve were distributed in the oral mucosa between the palatoglossal arch and the mandibular molar region. Two to eight collateral branches arose from the main trunk of the nerve, and the configuration of branching was classified into three types. More distally, the lingual nerve started to communicate with the hypoglossal nerve before passing the anterior border of the hyoglossus muscle. Nerve communications were also found in the main body and near the apex of the tongue. A thorough understanding of the collateral branches near the tongue, and the communication with the hypoglossal nerve inside the tongue, will help to prevent functional disorders from local anesthesia and oral surgical procedures associated with the lingual nerve. Clin. Anat. 32:635-641, 2019. © 2019 Wiley Periodicals, Inc.

A morphological study of the multi-posterior superior alveolar canals of maxilla in the Japanese macaque by cone-beam computed tomography.

The posterior superior alveolar canal (PSAC) composed of several canals which contains vessels and nerve in molar region of the maxilla of Japanese macaque. The PSAC of maxilla run to the maxillary sinus. However, the PSAC and accessory canal (AC) of the maxilla in the Japanese macaque (JM) is unknown in morphological features in the maxilla. The purpose of this study was to describe the PSAC of the primates and to determine whether this structure could be used as a model for the human clinical condition. In this study, we showed the course of PSAC structure of the 23 JMs (male: n = 15; female: n = 8) using a cone-beam computed tomography apparatus. In the results, we classified a type to have one AC toward, a type to have two ACs toward, and three ACs in a type to have in PSAC. The main canal have some bony branch canals (BBCs) composed of 3 types (no BBC, one BBC, two BBCs). These canals and they run downward and supply to MS, these roots of maxillary molar region of the craniofacial skeleton in contrast to numerous small accessory canals with no nerve and vessels observed in the posterior regions in maxilla. These morphology features may give useful information about MS in dental treatment human model.

Angle between the common and internal carotid arteries detected by ultrasound is related to intima-media thickness among those with atherosclerotic disease.

OBJECTIVES: Although carotid artery structural variations have been detected by ultrasound, their clinical significance is not fully understood. The objective of this study was to determine whether the angle between the common carotid artery (CCA) and the internal carotid artery (ICA), designated angle α, an ultrasound-detectable carotid artery structural variation, is related to carotid artery intima-media thickness (IMT), a surrogate marker for carotid atherosclerosis. METHODS: As a cross-sectional study, we measured angle α in routine carotid artery ultrasounds from 176 subjects (130 men) with atherosclerotic disease/risk factors that attended Kouseiren Hospital in Kagoshima City, Japan between August 2007 and April 2009. We evaluated the correlation between the angle α and CCA- or ICA-IMT. RESULTS: Angle α was weakly correlated with age but significantly correlated with ICA-IMT. The correlation was stronger in subjects with an ICA-IMT ≥ 0.5 mm than in those with an ICA-IMT < 0.5 mm (Right side r = 0.475 vs. 0.246, Left side r = 0.498 vs. 0.301, respectively). Upon multivariate logistic regression analysis, angle α and serum low-density lipoprotein cholesterol were independent explanatory variables for ICA-IMT. CONCLUSION: Angle α is related to ICA-IMT in subjects with atherosclerotic disease or risk factors in this study.

Differences in the morphology of the maxillary sinus and roots of teeth between Macaca fuscata and Macaca fuscata yakui determined using cone beam computed tomography.

The Japanese macaque is an endemic species consisting of two subspecies: Macaca fuscata fuscata (MFF) and Macaca fuscata yakui (MFY). The MFY is indigenous to Yakushima Island and represents a subspecies of MFF that lives from Honshu to Shikoku and Kyushu, Japan. However, the differences in the skulls of the MFY and MFF are unknown, despite these subspecies having different skull sizes. The maxillary sinus (MS) indicates that the features of the frontal view reflect the transversal growth of the maxilla of the skull. In this study, we show the MS structures of the MFF (n = 9, 18 sides) and MFY (n = 10, 20 sides) using a cone-beam computed tomography instrument. Base on three-dimensional (3D) reconstructed images the MS and nasal cavity were found to present almost to no significant differences between MFF and MFY. However, we designated three classifications of the sinus floor based on the 3D MS images of these Japanese macaques: a round-like shape (type a, MFF = 66.7% (12/18), MFY = 45% (9/20)), a flat-like shape (type b, MFF = 22.2% (4/18), MFY = 35% (7/20)), and an irregular shape (type c, MFF = 11.1% (2/18), MFY = 20.0% (4/20)). The sinus floor shapes of the MFF were mostly type a, while those of the MFY were mostly type b. The prevalence of a root contacting the cortical bone is higher in the canine (26.7%, (8/30)) and second premolar (20%, (6/30) of the MFY at the nasal cavity, moreover, this value is higher in the third molar (42.9%, (9/21)) of the MS in the MFY. These results suggest that the features of the floor of the MS are related to the differences in maxillary root apices teeth between MMF and MMF.

Communication between the buccal nerve (V) and facial nerve (VII) in the human face.

Terminal arrangements of communicating branches between the buccal nerve (V) and the facial nerve (VII) have yet to be precisely determined. To clarify distributions and relationships to facial muscles, detailed morphological examination of the two nerves was performed in the buccal region. The facial skin and underlying tissues of three cadavers were removed en bloc from the surface of the skulls and dissected from outside and inside. Arrangements of the facial muscles, nerves, and associated structures were observed. In all specimens, the communicating buccal nerve (CBN) was detected, largely covering the buccal region. The CBN gave off multidirectional twigs around the facial vein, some of which reached the anterior part of the zygomaticus major muscle. Several twigs of the CBN joined proximally with the zygomatic and buccal branches of the facial nerve. Ramified junctions that interconnected the lower zygomatic and upper buccal branches of the facial nerve were observed near sites where the CBN joined. Anterior twigs of the CBN supplied the longitudinal area lateral to the mouth, where many muscles converged. This study presents a precise morphological pattern of the CBN, suggesting functional contribution of the CBN to control of orofacial movements.

Morphological study of the human chondroglossus muscle in Japanese.

The chondroglossus muscle was macroscopically studied to clarify its fundamental morphology. This muscle was present in all of the 100 tongue halves examined in Japanese cadavers. In 14% of the specimens, however, the muscular fibers were sparse and vestigial. Originating mainly from the medial side of the lesser cornu of the hyoid bone, the chondroglossus muscle passed upward to penetrate the inferior longitudinal muscle of the tongue, and immediately entered the genioglossus muscle. Ascending inside the genioglossus muscle, it's bundles spread, taking a broom head or a fan-like shape. Thereafter it reached the submucosal layer in the root of the tongue, changed the direction from upward to forward, and terminated diffusely, never going past the sulcus terminalis. The origin, course, and spreading manner of the chondroglossus muscle were quite different from those of the hyoglossus muscle. The nerve fiber supplying the chondroglossus muscle was a ramus from the first lateral branch of the hypoglossal nerve. It should be considered a separate extrinsic lingual muscle independent of the hyoglossus muscle, although they have a phylogenetically close relationship.