**Core Concept**
The coronal CT paranasal sinuses is a radiological imaging technique used to visualize the paranasal sinuses in a coronal plane. This plane is particularly useful for assessing the ostiomeatal complex, the drainage pathway of the maxillary and frontal sinuses. The coronal CT scan provides a detailed view of the sinuses, orbits, and surrounding structures.

**Why the Correct Answer is Right**
The frontoethmoid recess is a small, slit-like structure located in the anterior part of the ethmoid bone. It is not visible on a coronal CT paranasal sinuses scan because it is oriented in a sagittal plane. In contrast, the ostiomeatal complex, orbits, and sinus cavities are all well-visualized on a coronal CT scan. The frontoethmoid recess is a small structure that is better evaluated on a sagittal or axial CT scan or on a 3D reconstruction.

**Why Each Wrong Option is Incorrect**
**Option A:** The ostiomeatal complex is a critical drainage pathway for the maxillary and frontal sinuses, and it is well-visualized on a coronal CT paranasal sinuses scan.
**Option B:** The orbit is a structure that is adjacent to the paranasal sinuses, and it is easily seen on a coronal CT scan.
**Option C:** The sinus cavities, including the frontal, maxillary, and ethmoid sinuses, are all visible on a coronal CT paranasal sinuses scan.

**Clinical Pearl / High-Yield Fact**
The coronal plane is optimal for evaluating the ostiomeatal complex, but a sagittal or axial view may be necessary to assess the frontoethmoid recess or other structures oriented in a different plane. Familiarity with the orientation and visualization of different structures on various CT scans is essential for accurate diagnosis and treatment planning.

**✓ Correct Answer: D. Frontoethmoid recess**