Paranasal sinus

{
  "id": "MLC-T-ENV-020221",
  "term": "Paranasal sinus",
  "field": "Environment",
  "term_source": "Paranasal Sinus",
  "definition": "1. Air-filled extension of the respiratory part of the nasal cavity into the frontal, ethmoid, sphenoid, and maxillary cranial bones. They vary in size and form in different individuals and are lined by the ciliated mucous membranes of the nasal cavity.\n\n2. Any of various sinuses (as the maxillary sinus and frontal sinus) in the bones of the face and head that are lined with mucous membrane derived from and continuous with the lining of the nasal cavity.\n\n3. One of many small hollow spaces in the bones around the nose. Paranasal sinuses are named after the bones that contain them: frontal (the lower forehead), maxillary (cheekbones), ethmoid (beside the upper nose), and sphenoid (behind the nose). The paranasal sinuses open into the nasal cavity (space inside the nose) and are lined with cells that make mucus to keep the nose from drying out during breathing.",
  "subject": "Biological substances",
  "references": [
    "NIH Genetics Home Reference Glossary",
    "National Cancer Institute Glossary"
  ],
  "url": "https://mlchart.com/terminology/environment/paranasal-sinus/"
}