The margin of the mandibular foramen

Mandibular foramen

The Mandibular foramen is an opening on the internal surface of the ramus for divisions of the mandibular vessels and nerve to pass.-Contents:...

 is irregular; it presents in front a prominent ridge, surmounted by a sharp spine, the lingula mandibulæ

Lingula of mandible

The margin of the mandibular foramen is irregular; it presents in front a prominent ridge, surmounted by a sharp spine, the lingula of the mandible which gives attachment to the sphenomandibular ligament; at its lower and back part is a notch from which the mylohyoid groove runs obliquely downward...

, which gives attachment to the sphenomandibular ligament

Sphenomandibular ligament

The sphenomandibular ligament is a flat, thin band which is attached above to the spina angularis of the sphenoid bone, and, becoming broader as it descends, is fixed to the lingula of the mandibular foramen...

; at its lower and back part is a notch from which the mylohyoid groove runs obliquely downward and forward, and lodges the mylohyoid vessels and nerve.

Behind this groove is a rough surface, for the insertion of the Pterygoideus internus.