Sacrococcygeal Synostosis - A Case Report

A sacrum is a triangular, flat bone formed by fusion of five sacral vertebrae creating four pairs of sacral foramina which transmit sacral nerves. Fusion of sacrum cranially with 5th lumbar vertebra or caudally with 1st coccygeal vertebra is some rare anatomical variations that results in the increase of number of sacral foramina and thus variation in the passage way of sacral and coccygeal nerves. A dry specimen of sacrum bone with 5 pairs of sacral foramina was observed during osteology demonstration at Department of Rachana Sharir, Sri Dharmasthala Manjunatheshwara College of Ayurveda and Hospital, Hassan, Karnataka. Extra 5th pair of sacral foramina in this bone was formed due to synostosis of 1st coccygeal vertebra with lower end of sacrum. Such type of variation has paramount importance in clinical field because it may cause prolonged second stage of labour or perineal tear and influence the caudal epidural block anaesthesia during surgical interventions.