Mother of a 10 year old male child is concerned that he appears smaller than other boys of his age. Intraoral examination reveals that the patient is in his mixed dentition stage. Permanent incisors and 1st molars are found to be present. Mandibular permanent canines are erupting and maxillary deciduous molars are present. Physical growth status of a child may vary from the chronologic age in many children, but it correlates well with skeletal age. Which is the best radiographic analysis to ascertain the skeletal age of this patient?