Fig. 1

Modified Neer classification. The modified Neer classification defines displacement of the fragment as separation of more than 1 cm or angulation of more than 45° from the humeral head fragment. a 1-part fracture. The humeral head stays together with the other segments. b 2-part fracture. The humeral head with the tuberosities is rotated to the humeral shaft. c 3-part fracture. The humeral head is separated from the humeral shaft and greater tuberosity. d 4-part fracture. The humeral head is displaced from the other 3 segments