What is the external oblique ridge?

• A. A bony projection on the lingual surface of the mandible.
• B. An extension of the anterior border of the mandibular ramus projecting backward.
• C. An extension of the anterior border of the mandibular ramus projecting forward.
• D. A depression along the inferior border for nerve passage.

Answer: (C)

The external oblique ridge is a raised line on the outer (buccal) surface of the mandible that marks the forward extension of the anterior border of the ramus as it continues onto the body of the mandible. In other words, it’s an extension of the ramus’ front edge that runs forward along the external surface, helping delineate the masseter attachment area. It isn’t on the lingual surface, it doesn’t extend backward, and it isn’t a depression for nerve passage.