Ativastic epiphysis is a phylogenetically independent bone which gets attached to the host bone secondarily to recieve nutrition. Eg are coracoid process of scapula, posterior tubercle of talus or trigonum. Classification of epiphysis : Pressure epiphysis : head of femur and humerus. Traction epiphysis : trochanter of femur and tubercle of humerus. Ativastic epiphysis : coracoid process of scapula, posterior tubercle of talus or trigonum.