The inferior alveolar nerve is the one of the large branches of the mandibular division of the trigeminal nerve. It is vulnerable during surgical procedures of the mandible. Despite its importance, no anatomical and histological examination has been conducted to provide a detailed cross-sectional morphology of the mandibular canal according to dental status. Therefore, the present study aimed to identify the position of the mandibular canal through direct measurement and to determine the branches of the inferior alveolar nerve through histologic examination. The area between the anterior margin of the third molar and the anterior margin of the second premolar of dentulous, partially dentulous, and edentulous hemimandible specimens (n = 49) from 26 human cadavers was serially sectioned into seven segments, and specific distances were measured using digital calipers. Following this, 5-microm cross-sections were prepared along the mandibular canal and mental foramen, and examined by fluorescence microscopy. The mandibular canal was located at a mean distance of 10.52 mm above the inferior margin of the mandible. The mean maximum diameters of the mandibular canal, inferior alveolar nerve, inferior alveolar artery, and inferior alveolar vein were 2.52, 1.84, 0.42, and 0.58 mm, respectively. This study found that the inferior alveolar nerve often gives rise to several branches at each level (range 0-3). To minimize the risk of injury, knowledge of the small branches of the nerve and of the detailed findings regarding the position of the mandibular canal reported here should be considered when planning mandibular surgery, especially during implant placement.
The aim of this study was to determine number of ocular vortex veins, their scleral coordinates, and their relationship with nearby extraocular muscles. Sixty intact cadaver orbits having no history of eye or orbital disorders during life were carefully dissected under stereomicroscopic magnification to expose vortex veins and their exit sites from the eyeball. The number of vortex veins per eye varied from four to eight. Eyes having four (35%) or five (30%) vortex veins were observed most frequently. Three eyes (5%) had eight vortex veins. Although the incidence of the vortex veins was variable, there was at least one vein in each quadrant of the sclera. Knowledge of the approximate location of the vortex vein exit sites is very important for surgeons because damage to these veins during eye surgery could produce potential complications, especially choroidal detachment.
The musculus extensor digiti medii proprius and musculus extensor digitorum brevis manus are anomalous extensor muscles of the hand. During the routine dissection of a white male cadaver a musculus extensor digiti medii proprius was seen on both hands and a musculus extensor digitorum brevis manus was seen on the left hand. The extensor medii proprius has a belly originating from the distal third of the ulna near the extensor indicis proprius and its tendon is inserted into the dorsal aponeurosis of the middle finger on both hands. On the left hand there was another anomalous muscle (musculus extensor digitorum brevis manus) which originated from the distal end of the radius, carpal ligaments and carpal joint capsule and inserted on the tendon of the extensor digiti medii proprius. This case is a multivariation of the hand extensor muscles and a musculus extensor digitorum brevis manus inserting on the musculus extensor digiti medii proprius has not been reported previously.
Objective This study aims to determine the topographic localization of the stylomastoid foramen (SF) and its morphometric relationship with the surrounding bony landmarks.
Design A descriptive anatomical study.
Setting Anatomy Laboratory of the Faculty of Medicine.
Participants Measurements were performed on 53 dry temporal bones.
Main Outcome Measures On the inferior and lateral aspects of photographic images, lines and angles were defined. The most lateral end of the SF (SF1) and the transverse medial–lateral line that passes through the upper end of the anterior border of mastoid process (line 1) were used as reference points for topographic evaluation. The upper end of the anterior border of mastoid process (A) and the tip of mastoid process (B) were considered in defining angles. The dates about SF were evaluated using the ImageJ 1.46r software and digital caliper.
Results SF1 was classified into three different types based on its topographical localization, stated as Type 1, Type 2, and Type 3. In Type 1, SF1 was located anterior to line 1 (54.7%). SF1 was located posterior to line 1 in Type 2 (34.0%). SF1 was located just over line 1 in Type 3 (11.3%). We also detected angular variations between these types in the inferior and lateral aspects.
Conclusions The recommended angles of application are 30 degrees on the horizontal plane and 55 degrees on the sagittal plane for Type 1 when point B is considered. A needle length below 10 mm is more suitable to minimize the potential complications of the nerve block.
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