The Maxillary Sinus is largest of all the Sinuses and is located in the maxilla. The air filled cavity is lined by pseudo stratified columnar epithelium. The Maxillary sinus is pyramidal in shape, Boundaries of Maxillary sinus are the Medial wall is formed by the lateral wall of nasal cavity, the roof is formed by floor of orbit, the floor is formed by alveolar process of maxilla. The Maxillary sinus communicates with the nasal cavity through the ostium which is located near the top of maxillary sinus, in some cases there may be an accessory opening posterior and inferior to the main opening.

Maxillary sinus begins to develop as an invagination of the epithelium of the lateral wall of the nasal fossa at about 3 months in utero. The size of sinus is very small at birth and gradually increases in size until adulthood. The other paranasal sinus are frontal, ethmoidal, n sphenoidal sinuses.

Classification of Diseases of the Maxillary Sinus:

Developmental Anomalies: 

  • Aplasia: When the Maxillary Sinus fails to develop fully
  • Hypoplasia: When the Maxillary Sinus fails to develop partially
  • Agenesis: Complete absence of Maxillary Sinus
  • Supernumerary Maxillary Sinus: Multiple Maxillary Sinuses

Inflammatory diseases of Maxillary Sinus:

  • Maxillary sinusitis: Inflammation of the Sinus
  • Mucositis: Inflammation of the mucous membrane of Maxillary sinus
  • Empyema: Pus filled in Maxillary Sinus due to Bacterial or Viral infections
  • Antroliths: Calcified mass present in the Maxillary Sinus
  • Antrochoanal Polyps (ACPs): These are benign polypoid lesions in the maxillary antrum. They appear as Dome shaped Radiopacity.

Radiographic Features of Diseases of Maxillary Sinus

Cysts of Maxillary Sinus: The Cysts of the Maxillary sinus are divided into two types –

  • Odontogenic: Periapical, Dentigerous, Keratocysts and Primordial cysts
  • Non-Odontogenic: Mucous Retention cyst (Radiographically appears as a ball like radio-opacity without cortical outline), Serous Retention cyst (Radiographically appears less radiopaque when compared to Mucous Retention Cyst), Mucocele

Traumatic Diseases of Maxillary Sinus:

  • Oro-antral Fistula: It is a communication between the Maxillary Sinus and the Oral Cavity.
  • Fractures:
  • Root piece or Foreign body in sinus: A root piece can be dislodged into the Sinus during extraction procedure of the Second Premolar or the Maxillary 1st and 2nd molars. They appear as Radiopaque bodies in the Sinus cavity

Benign Tumors of Maxillary Sinus: Odontogenic Tumors, Antral papilloma, Cholesteatoma, Antral papilloma, Osteoma, Odontomes.

Malignant Tumors of Maxillary Sinus: Squamous cell carcinoma, Adenocarcinoma, metastatic, carcinoma

These are the Radiographic features of diseases of Maxillary Sinus which need Radiographic Diagnostic help to determine the Treatment plan.