ACDF Ethiopian population First metatarsal head Kommerell’s diverticulum M sternalis Medicine aberrant obturator artery aberrant subclavian artery anatomic landmarks anatomic variation anatomical landmarks anatomical variation anatomical variations anatomographical variation anatomy anatomy and histology ankle arteria lusoria artery tortuosity bulbs of the vestibule cancellous bone density celiac artery celiac artery compression syndrome cortical bone thickness dental cone-beam computed tomography dental implant site diaphragm dysphagia lusoria external iliac branching variations fibula