The interforaminal region is usually considered as a safe region in the chin bone graft without important vital anatomical structures to be damaged. But the accurate anatomy of the interforaminal region, with its potential clinical relationships, is controversial. Moreover some complications suggesting damage of incisive terminal branches after chin bone harvesting are reported such as sensory discomfort and pain etc. In order to verify incisive innervation of symphyseal area, we examined the cross-sectional CT scan images taken for preoperative planning of implant placement with chin bone graft and some parameters were measured; (1) visuality rating of incisive canal (2) vertical and horizontal diameter of canal (3) distance from lower border of the incisive canal to the lower border of the mandible (4) shortest distance from anterior border of the incisive canal to the anterior border of the mandible. We report the positive outcome that decrease the complications related with the damages of incisive branch during bone harvesting from the chin.