2Running title: Implants near the midline mandibular lingual canal Abstract Purpose: To determine the position and occurrence of the midline mandibular canal (MLC) in the various age, sex, population and dentition groups. The average distances from the MLC to a planned mandibular midline implant and the inferior mandibular border were measured. Materials and methods: Cone beam computed tomography (CBCT) was used to scan 122 mandibles (31 black males; 28 black females; 32 white males and 31 white females). Midsagittal sections in the reconstructed images of edentulous mandibles or sagittal sections through the socket of the 41 tooth (FDI nomenclature) in dentate mandibles were made. A measurement of 6 mm across buccolingually (BL) was delineated with the caliper tool indicating the minimum dimensions for placement of an implant. In dentate cases where the BL distance was in excess of 6 mm, the caliper was placed across the deepest part of the socket as a marker to determine the bone dimension available below the socket for implant placement. From these markers a vertical line was dropped to the MLC to measure the available bone. Results: The MLC was a consistent finding within the anterior mandible.A statistical significant difference in bone availability amongst the sexes and with dentition pattern was found indicating that edentulous female patients were particularly at risk of injury to the vessels of the midline lingual canal during implants in that area. Conclusion: Immediate implants in the position of lower central incisors are regarded as a safe procedure as is the placement of interforaminal implants in the anterior mandible. Clinicians should however take note of the position of the midline mandibular lingual canal and approach this area with caution, especially if the alveolar ridge is to be reduced before implant placement.

Purpose: Several surgical and clinical procedures are performed in the area of the medial compartment of the thigh. This places the obturator nerve and its branches in potential danger of injury. This study aimed to provide a clear description of the anatomy and course of the obturator nerve and its branches to assist surgeons and clinicians in the safe performance of various pelvic procedures. Methods: One hundred and one (101) formalin-fixed were dissected. Dissections were performed just lateral to the lumbar vertebra to describe the origin of the obturator nerve. The course of the nerve, with its relations, was observed and recorded until it terminated in the medial thigh. The location of the obturator nerve within the obturator foramen was quantified by measuring the distance from three bony landmarks of the obturator foramen to the nerve. Findings: Variations were observed in the root origins of the obturator nerve, its course in the abdomen, bifurcation patterns and the innervation patterns of its terminal branches. Conclusion: The results of this study may be used in the pre-operative preparation of surgeons that are to perform surgery in the area of the obturator foramen. The study serves to assist in expanding the knowledge on the anatomy of the obturator nerve and its branches in a South African context. These results should be verified in a clinical setting.

Abnormalities in the morphology of the corpus callosum have been found to be involved in cognitive impairments or abnormal behaviour in patients with mental disorders such as schizophrenia and bipolar disorder. The present study investigated morphological shape differences of the corpus callosum in a large cohort of 223 participants between normal, schizophrenic and bipolar patients on MRI scans, CT scans and cadaver samples. Healthy samples were compared to a mental disorder population sample to determine morphological shapes variations associated with schizophrenia and bipolar disorder. Landmark‐based methodology was used to contour the corpus callosum shape that served as standard positions to allow for radial and thickness partitioning in order to determine shape variations within the specific localised anatomical sections of the corpus callosum. Shape analysis was performed using Ordinary Procrustes averaging and superimposing landmarks to define an average landmark position for the specific regions of the corpus callosum. No significant global shape differences were found between the different mental disorders. Schizophrenia and bipolar shapes differed mostly in the genu‐rostrum, posterior body, isthmus and splenium. Sample group comparisons yielded significant differences between all groups and global measurement parameters and in various sub‐regions. The findings of the present study suggest that the corpus callosum in schizophrenia and bipolar differs significantly compared to healthy controls, specifically in the anterior body and isthmus for schizophrenia and only in the isthmus for bipolar disorder. Shape changes in these regions may possibly, in part, be responsible for the symptoms and cognitive impairments observed in schizophrenia and bipolar disorder.

Person-specific three-dimensional computational modelling plays a vital role in modern day research of cochlear implants to assist in understanding the neural interface of the cochlea and implanted electrode array. Further improvements are made to these models as more parameters are included. Landmark assessment provides information and is frequently used to register co-ordinates for model generation as it captures small variations. Objectives: The objective of this study is to identify and define landmarks to describe the internal auditory canal adequately for inclusion in the three-dimensional computational models of the cochlea and its surrounding structures. Participants: Retrospectively collected computer tomography scans of live human cochleae were collected. Descriptive and comparative statistics were used to describe the data obtained from the scans. Results: The mean anterior-posterior (AP) diameter at the base on the basal turn, the AP diameter at the midpoint of the IAC, the anterior and posterior length of the internal acoustic canal were measured. 57.14% of the internal acoustic canals observed presented with a cylindrical, 40.48% was funnel-shaped and 2.38 % was bud-shaped. A statistically significant difference was found between the diameters of the male and female internal acoustic meatii. Conclusion: This paper serves as a reference providing a landmark set for the description of the internal acoustic canal for inclusion in three-dimensional computational reconstruction of the cochlea and surrounding structures.

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