17. A 42-year-old female fell on her outstretched left arm one week ago and suffered injuries to her hand, wrist, arm, shoulder, and neck. Since the fall, she has been experiencing constant numbness and tingling in the 4th and 5th fingers of the left hand and a feeling of weakness in the hand. Associated with the primary complaints are tightness in forearm and shoulder, and some neck achiness. On examination, the chiropractor found that she was unable to keep her thumb adducted against her hand when the chiropractor was resisting the motion. Based on the symptoms and finding, in which following body regions should the chiropractor focus his assessment to get the correct diagnosis?