Maxillary Sinus PDF

Maxillary Sinus

Anatomical facts and location:

√ The largest para-nasal sinuses.
√ Situated in the maxilla.
√ Has pyramidal shape.
√ Lateral nasal bone forms its base.
√ Apex headed towards the zygomatic bone.
√ Canine fossa, orbital floor and hard palate form the pyramidal walls.
√ Communicates with nasal cavity through maxillary ostium, in the posterior end of hitus simlunaris of middle meatus.

Maxillary Sinus Maxillary Sinus

Anatomical morphology:

√  Size varies from one person to another.
√  Asymmetry existed in the same individual.
√  Small in children and grows up with aging.
√  Average height is about 3.5 cm, depth 3.2 cm and width 2.5 cm.
√  Capacity of about 15 cc.
√  Divided into several compartments by bony septa (underwood’s septa).
√  Lined with pseduo-stratified columnar ciliary epithelium (schneiderian membrane).

Maxillary Sinus

Maxillary Sinus Maxillary Sinus

Relation with other structures:

√ Alveolar bone and dentition.
√ Nasal cavity and nasopharynex.
√ Orbital cavity and its contents.
√ Hard palate and oral cavity proper.
√ Pterygomaxillary fissure and its contents.
√ Neurovascular structures including infraorbital and superior alveolar nerve.

Maxillary Sinus


√  Develops from invagination of the mucous membrane of middle meatus of the nasal cavity at about the 3rd month of intrauterine life.
√  Fully development reaches with the age of 16 years.
√  Loss of permanent teeth and alveolar bone may make the sinus to appear huge in size.

Blood supply:

Blood supply from facial, maxillary, infraorbital, greater and lesser palatine arteries and lateral and posterior nasal branches of sphenopalatine artery.
Venous drainage to the anterior facial vein, sphenopalatine vein and pterygopaltine plexus.

Maxillary Sinus

Nerve supply:

√  Infraorbital nerve.
√  Posterior, middle and anterior superior alveolar nerves.
√  Greater and lesser palatine nerves.

Maxillary Sinus

Lymphatic drain:

The lymphatic drain of the sinus is through the nose or the submandibular lymph nodes.


Unknown but the following functions have been proposed:

√  Speech and voice resonance.
√  Reduce weight of skull.
√  Warmth inspired air.
√  Filtration of inspired air.
√  Immunologic barrier ( body defense).


  1. Congenital anomalies.
  2. Inflammatory diseases.
  3. Cysts and odontogenic infection.
  4. Bone metaplasia and benign tumors.
  5. Neoplasia.
  6. Trauma.

Maxillary Sinus

Congenital anomalies:

√  Cleft palate.
√  Facial fistula and cleft.
√ Cystic formation.
√  Atresia.

Inflammatory diseases:

√  Bacterial infection.
√  Bacterial infection secondary to viral infection.
√  Fungal infection.

Acute sinusitis:

Suppurative or non suppurative inflammation of the mucosal lining of the sinus. It involves one or both sinuses.


√  Secondary to hay fever and allergic rhinitis.
√  Secondary to acute rhinitis (common cold) and URT infection.
√  Bacterial infection due to: dental sepsis, swimming and diving, trauma and foreign body dislodgment.

Sings and symptoms:

√  Headache.
√  Pain and tenderness.
√  Nasal obstruction.
√  Nasal discharge.
√  Toxic manifestations.
√  Heavy filling with bending.
√  Nasal congestion.
√  X-ray and transillumination findings.


√  Rest and fluid and mouth hygiene.
√  Antibiotics (C&S); pneumococci and streptococci are the most causative organisms.
√  Analgesics and antihistamines.
√  Local treatment (decongestant and steam inhalation).

Chronic sinusitis:

It is a chronic type of infection affected the mucosal lining of one  or both sinuses, resulted in mucopus or pus collection. A polypoidal type of inflammation can lead to formation of multiple or single mucosal polyps.


√  As a consequence of non resolved acute sinusitis.
√  Dental abscesses.
√  Virulent organism with low resistance.
√  Foreign body dislodgement or trauma

Signs and symptoms:

√  Headache.
√  Nasal obstruction
√  Nasal discharge.
√  Fatigue.
√  Hyposmia/ cacosmia.
√  Transllumination findings.
√  Proof puncture.


√  Antibiotics.
√  Systemic decongestants.
√  Sinus wash-out.

Maxillary Sinus

Mycotic infection:


Opportunistic infection caused by maxillary sinus flora fungi environment in susceptible individual, leads to obliteration of the sinus space and erosion of its bony components.

Complications of sinusitis:

  • Orbital abscess and orbital cellulites.
  • Intracranial abscesses.
  • Meningitis.
  • Cavernous sinus thrombosis.
  • Spread of infection to neighboring sinuses, structures and organs.
  • Osteomyelitis.
  • Gastrointestinal disturbances.

Cysts and odontogenic tumors:

Odontogenic cysts:

√ radicular cysts.
√ residual cysts.
√ dentigerous cysts.
√ premordial cysts.

Non-odontogenic cysts.

Mucocele and retention cysts.

Odontogenic tumors:

√ ameloblastoma.
√  Myxoma.

Bone metaplasia and benign tumors:

√  Fibrous dysplasia.
√  Ossifying fibroma.
√  Transitional papilloma.
√  Osteoma.
√  Giant cell lesions.


√  Squamous cell carcinoma.
√  Adenocarcinoma.
√  Sarcoma (osteosarcoma).
√  Ewing’s sarcoma.

Maxillary Sinus


√  Tuberosity fracture.
√  Dentoalveolar fracture.
√  LeFort’s fractures.
√  Zygomatic complex fracture.
√  Pure and impure orbital floor fractures.
√  Establishment of oro-antral fistula.

Clinical examination:


√ Assess asymmetry.
√ Color of overlaying skin.


√  Tenderness.
√  Swelling and expansion.
√  Depression.

Examination of nasal passage

√ Nasal patency.
√ Pus discharge.
√ Nasal polyps.
√ Erythema, redness, change in the color of nasal mucosa.


Diagnostic sinus lavage

√ sinus rinsing through the canine fosaa.
√ Nasal antrostomy.

Maxillary Sinus Maxillary Sinus

Radiographical examination:

Routine radiographical examination

√ Orthopantomogram (OPG)
√ Occipitomental (water’s view), with lateral tilt.

Maxillary Sinus Maxillary Sinus
Special investigation and radiographical examination
  • Sinuscopy
  • Sinogram
  • CT scan
  • MRI
  • Microbiology and histological examination:
  • Culture and sensitivity and biopsy.