Structure D is the:

Structure D is the:

• A. Zygomatic arch
• B. Anterior nasal spine
• C. Bony nasal septum (perpendicular plate of ethmoid and vomer)
• D. Angle of mandible

Answer: (B)

The main concept is recognizing a facial bone landmark on radiographs. The anterior nasal spine is a sharp projection at the lower border of the nasal aperture where the maxilla meets the nasal bones. It sits at the front of the face, at the base of the nose, and is a prominent midline point that radiographs can clearly show. This makes it the best choice because it is the anterior projection at the base of the nasal cavity, formed by the maxilla and nasal bones. The zygomatic arch is a lateral cheekbone arch, not at the midline or at the nasal base. The angle of the mandible is the jaw’s lower corner, far from the nasal region. The bony nasal septum lies inside the nasal cavity and is composed of the perpendicular plate of the ethmoid and vomer, not a surface projection seen on the exterior of the skull.

The main concept is recognizing a facial bone landmark on radiographs. The anterior nasal spine is a sharp projection at the lower border of the nasal aperture where the maxilla meets the nasal bones. It sits at the front of the face, at the base of the nose, and is a prominent midline point that radiographs can clearly show.

This makes it the best choice because it is the anterior projection at the base of the nasal cavity, formed by the maxilla and nasal bones. The zygomatic arch is a lateral cheekbone arch, not at the midline or at the nasal base. The angle of the mandible is the jaw’s lower corner, far from the nasal region. The bony nasal septum lies inside the nasal cavity and is composed of the perpendicular plate of the ethmoid and vomer, not a surface projection seen on the exterior of the skull.