This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Avascular necrosis of head of femur occurs commonly at : 
Select and explain. 
A. Subcapital region, B. Transcervical region, C. Subchondral region, D. Trochanteric region
A: Subcapital region
Answer: A: Subcapital region 
Explanation: Avascular necrosis is common with fractures to the subcapital region. Subcapital fractures damage the ascending vessels, thereby causing avascular necrosis and nonunion. Subcapital is the most common location for a femoral fracture. Ref: Srinivasan R.C., Tolhurst S., Vanderhave K.L. (2010). Chapter 40. Ohopedic Surgery. In G.M. Dohey (Ed), CURRENT Diagnosis & Treatment: Surgery, 13e.