Introduction:The Foramen Magnum (FM) lies in an anteromedian position and leads into the posterior cranial fossa. It is oval and wider behind, with its greatest diameter being anteroposterior. It contains the lower end of the medulla oblongata, meninges, vertebral arteries and spinal accessory nerve. The apical ligament of dens and the tectorial membrane pass through it, to attach to the basiocciput. Anteriorly the margin of foramen magnum is slightly overlapped by the occipital condyles. Transcondylar, supracondylar, and other lateral surgical approaches provide access to various foramina on the base of skull and prevent broad retraction of the neural structures passing through them Morphometric analysis of foramen magnum plays important role in transcondylar approach. Aim: The study was designed to measure the diameters and shape of foramen Magnum and correlates the measurements with clinical importance, as its shape and variation in diameters will be of great help to operating surgeon during surgical procedures. Materials and Methods: Forty dry human skulls were studied during this research work. Skulls were taken from the department of anatomy, dayanand medical college and hospital, Ludhiana and other medical college. Results: During this study the mean MAPD was 35.42mm, the MTD found to be 27.90mm The Foramen magnum Index found to be 17.20mm. The shape of foramen magnum found mostly was oval in 60% cases. The anterior inter condylar distance found to be 18.01 to 20.00mm. Whereas middle intercondylar distance is 20.1 to 22mm and posterior was 30.01 to 32.00mm. Conclusion:The present study had observed the variation in the measurements of skull base foramen magnum which were different from observations by the western studies because of difference of race and geographical areas.

The Retromolar foramen/canal are one of the non-metric variants of the mandible located in the retromolar fossa of the mandible behind the 3 rd molar of mandible. These are obviously of profound dental and surgical importance. The aim of the study was to know the prevalence of retromolar canal/foramen in north Indian population. In the present study, 35 dry mandibles of unknown sex of north Indian origin were examined by naked eyes to know the incidence of retromolar foramen/canal. The retromolar foramen/canal was found in 6 mandibles (17.14%), bilaterally in 2 mandibles and unilaterally in 4 mandibles. We conclude that retromolar foramen /canal is of profound clinical importance.

Background: Mandibular foramen (MF), present on the medial surface of ramus of the mandible, leads to the mandibular canal through which inferior alveolar nerve (IAN) and vessels transmit. IAN block is a common anaesthetic procedure before dental and reconstructive surgeries. Surgeons usually do IAN block in their clinics and encounter failure of block because of variable position of MF.Objective: The present study was carried out to find the most common position of MF in north Indian population.Materials and Methods: Study was done on 50 dry adult human mandibles of unknown sex and age of north Indian origin. Height was measured from the angle of the mandible to the highest point on condyloid process. Mid point of the line joining these points was noted. The position of MF was observed in relation to pre noted mid point.Results: MF was placed below the level of mid point in 40 mandibles (80%). Conclusion:The knowledge of most common position of MF will help the surgeons to reduce the chance of unsuccessful IAN block.