Incisive fossa : shallow depression below the incisor teeth.
Gives origin to:-1. Mentalis 2. Parts of orbicularis oris.
B. Internal Surface: Concave in outline.
Mylohyoid ridge : (int oblique line): an oblique ridge running forward and downwards on each side from 3 rd Molar tooth to the symphysis menti; very prominent behind. It divides the int surface in to 2 areas.
a. Submandibular fossa below the line
b. Sublingual fossa above the line
Gives origin to :
mylohyoid muscle: throughout its whole length.
Sup constrictor muscle of pharynx: from its post end.
Groove for lingual nerve : a groove above the mylohyoid line but below the last molar tooth. It lodges lingual nerve. Above this groove sup constrictor muscle is attached.
Lower (inferior) border : continuous in front with the base of mandible.
Coronoid process : flat & traingular with the apex pointing upwards while the base is fused with upper & ant part of ramus. Its ant border is continuous with ant border of the ramus & the post border forms the ant boundary of mandibular notch.
Insertion of temporalis muscle: to the apex, margins, whole of medial surface and a part of lat surface close to the apex.