This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper Limb and Lower Limb, Subject name: Anatomy
All of following are examples of traction epiphysis except:- 
Select and explain. 
A. Tubercles of humerus., B. Posterior tubercle of talus., C. Trochanters of femur., D. None of above.
B: Posterior tubercle of talus.
Answer: B: Posterior tubercle of talus. 
Explanation: Epiphysis is the pa of bone which ossifies from the secondary centre. It may be of three basic types; 1) Pressure epiphysis:- it transmits the body weight and protects the epiphyseal cailage. E.g. heads of femur and humerus, condyles of femur and tibia. 2) Traction epiphysis:- it is produced by the pull of some muscles. E.g. trochanters of femur and tubercles of humerus. 3) Atavistic epiphysis:- it is phylogenitically an independent bone and is attached secondarily on a host bone to receive nutrition. E.g. coracoids process of scapula and posterior tubercle of talus or os trigonum.