What are the precautions to be taken when harvesting autogenous bone grafts from mandibular symphysis and ramus?

When harvesting grafts from the mandibular symphysis region, following structures should be protected:

 Incisive branch of the inferior alveolar artery which anastomoses with the artery of the opposite side in this region.

 Injury to the sublingual artery( branch of lingual artery) and submental artery( branch of facial artery) can result in life threatening haemorrhage. Excessive bleeding and formation of massive lingual, sublingual and submandibular haematomas due to arterial trauma can displace the tongue causing upper airway obstruction.Applied Basic Sciences When harvesting graft from the ramus region injury to the long buccal nerve and vessels and to the inferior alveolar nerve must be avoided.