Internal malleolus fractures and postoperative functional limitations are serious complications of deltoid ligament repair, reconstruction, while studies on conducting beak Anatomical structure classification of medial malleolus at home and abroad is reported rarely. Hence, this morphological study is mainly designed to investigate the anatomical morphological classification and clinical significance of medial malleolus based on CT three-dimensional reconstruction.From October 2018 to January 2021, 373 patients who underwent CT examination of malleolus medialis joint in the Jiang 'an Hospital of Traditional Chinese Medicine were observed. The medial malleolus was observed and classified, then geometric parameters were measured according to different medial malleolus types.According to the results of 373 cases, medial malleolus can be divided into 4 types: omega type (66%), radical sign type (16%), inverted triangle type (14%), and wave type (4%).There are four main shapes: omega, inverted triangle, radical sign, and wave in the medial malleolus of all normal ankles. The measurement of medial malleolus parameters according to medial malleolus in different shapes was of importance to guide smooth operation of medial malleolus fixation and deltoid ligament reconstruction and epidemiological.