Which sinuses drain into the middle meatus?

Which sinuses drain into the middle meatus?

• A. Frontal, maxillary, anterior and middle ethmoidal sinuses
• B. Frontal and sphenoid sinuses
• C. Maxillary sinus only
• D. All paranasal sinuses

Answer: (A)

Drainage from several paranasal sinuses empties into the middle meatus, a groove in the middle nasal cavity wall that collects mucus and conveys it to the nasal cavity. The frontal sinus drains into the middle meatus via the frontonasal duct and the semilunar hiatus. The maxillary sinus opens high on the medial wall into the middle meatus through its ostium. The anterior ethmoid air cells also drain into the middle meatus, through pathways around the ethmoidal infundibulum and the hiatus semilunaris. The middle ethmoid air cells likewise drain into the middle meatus. In contrast, the posterior ethmoid cells drain into the superior meatus, and the sphenoid sinus drains into the sphenoethmoidal recess above the superior meatus. Therefore, the sinuses that drain into the middle meatus are the frontal, maxillary, and the anterior and middle ethmoid sinuses.

Drainage from several paranasal sinuses empties into the middle meatus, a groove in the middle nasal cavity wall that collects mucus and conveys it to the nasal cavity. The frontal sinus drains into the middle meatus via the frontonasal duct and the semilunar hiatus. The maxillary sinus opens high on the medial wall into the middle meatus through its ostium. The anterior ethmoid air cells also drain into the middle meatus, through pathways around the ethmoidal infundibulum and the hiatus semilunaris. The middle ethmoid air cells likewise drain into the middle meatus. In contrast, the posterior ethmoid cells drain into the superior meatus, and the sphenoid sinus drains into the sphenoethmoidal recess above the superior meatus. Therefore, the sinuses that drain into the middle meatus are the frontal, maxillary, and the anterior and middle ethmoid sinuses.