Review Question - QID 218647

A 15-year-old lacrosse player comes to the clinic with a complaint of persistent right medial foot pain that is typically worse after long afternoon practice sessions. He was given rigid foot insoles for arch support by his pediatrician for his flat feet, but these seem to make his pain worse. An external oblique radiograph of the affected extremity is shown in Figure A. Which of the following inserts onto the structure associated with the cause of this patient's pain and is likely contributing to worsening pain with the use of the rigid arch supports?