The two root canals, root canal diverge and root canal branch et al have considerable incidence. Besides, mesial-distalroot canal walls of mandibular incisor teeth are thin.
下颌切牙中，双根管、根管分支和根管分歧都有一定的发生率。
2
Results:The distal transverse palmar arches(DIPA) were 73%, 19% and 8% in nail root cross section, distal and proximal nail root respectively.
结果：指动脉的远侧掌横弓位于甲根平面、甲根平面以远和以近者分别占73％、19％和8％。
3
Objective To investigate the diagnosis and treatment of the cervical nerve root coexisting with the distal nerve entrapment(Double crush syndrome).