The biomechanical importance of the costoclavicular ligament is well known; however, an extensive debate still exists regarding the amount of the medial clavicle that can be removed without injuring the ligament. The goal of this anatomic study in fresh cadavers is to measure the distance between the inferior articular surface of the medial clavicle and the most medial clavicular insertion of the costoclavicular ligament, as well as to verify whether there is a relationship between this measurement and the length of the clavicle. Dissection of 100 shoulders from 50 fresh cadavers was performed. All specimens were from male cadavers ranging in age from 17 to 65 years (mean, 37 years). Variation in clavicular length did not alter the distance between the inferior articular surface of the medial clavicle and the most medial clavicular insertion of the costoclavicular ligament, which in our study measured 1.26 cm. The costoclavicular ligament can extend as far as the inferior articular surface of the medial clavicle. We recommend identification of this ligament during surgeries for resection of the clavicle's proximal extremity.