<s>[INST] context: Mastoid process is a Traction epiphysis.Traction epiphysis is produced due to the pull of the muscles and therefore provide attachment to the muscle. for e.g., sternocleidomastoid muscle puts a traction upon the mastoid process.Note: The mastoid process does not begin to develop until the end of the second year. Before the mastoid process develops, the facial nerve is a subcutaneous structure and is in danger of being damaged by an incision behind the ear, if it extends too far down. Types of epiphysis: Pressure epiphysis Traction epiphysis Atavistic epiphysis Aberrant epiphysis -Aicular ends(takes pa in transmission of weight) Example- Head of femur - Nonaicular(does not take pa in transmission of weight) *Provides attachment to one or more tendons which exe traction on the epiphysis. Example- Tubercles of humerus, mastoid process. - Phylogenetically an independent bone, which in humans is fused to another bone Example- coracoid process of scapula Is not always present Example- Epiphysis of head of first metacarpal [/INST] question: Mastoid process is which type of epiphysis | options: A: Pressure B: Aberrant C: Atavistic D: Traction | answer: D </s>