ANSWER: (A) Maxillary sinusREF: Ballenger's Otorhinolaryngology: Head and Neck Surge by James Byron Snow, PhillipA. Wackym, John Jacob Ballenge centennial ed p. 506Indirect repeat ENT 2012 Session 1 (see details of Fibrous dysplasia)See APPENDIX-49 "PARANASAL SINUSES" APPENDIX - 49Paranasal Sinuses:Paranasalsinus(PNS)Status at birth1stRadiologicalEvidenceBestradiologicalviewAdult sizeDrains intoCommentsMaxillaryPresent4-5 monthsWaters'view/Ocdpitomental/nose-chinposition15 yearsMiddle meatusLargest PNS, capacity of 15 ml in an adult, Antrum of HighmoreEthmoidPresent1 yearCaldwellviewSizeincreases until teensAnterior & middle Etbmoid= middle meatus, Posterior Ethmoid= Superior meatusNumber varies from 3 to 18FrontalAbsent6 yearsCaldwellview7 years,Middle meatus6-7 ml capacitySphenoidAbsent4 yearsWater's view with open mouthBetween 15 years to adult ageSphenoethmoidalrecess2.2 cm x 2 cm x 2.2 cm.Also know:Streptococcus pneumoniae is the most common organism implicated to acute sinusitis in both adults and childrenIn children with cystic fibrosis, most common organism implicated to sinusitis is staphylococcus aureus.Chronic sinusitis is most commonly associated with s. aureus and <2 hemolytic streptococciAspergillus mucormycosis is the most common organism implicated to fungal sinusitis with maxillary sinus most frequently involvedWagner's granulomatosis is the most common granulomatous sinusitis with maxillary sinus most commonly involved.Acute sinusitis almost always involves single sinus, with ethmoid sinus being most common in children and maxillary in adults.Maxillary sinus is the most common location of chromic sinusitis in both children and adults closely followed by ethmoid sinus.(Note: To he more particular "Anterior ethmoid cells'' are most common site of chronic sinusitis in children but comparing sinuses as a whole maxillary becomes more common than ethmoid)Mucous retention cyst (different from mucocele) is most commonly found at maxillary sinus.Most common site of mucocele is frontal sinus (60%), least common at sphenoid sinus.Squamous cell carcinoma is the most common malignant tumor of sinuses with maxillary sinus most commonly involved (80%)Most common site of adenocarcinoma of sinus is ethmoid sinus.Brain abscess is the most common intracranial complication of sinusitis (as a whole)Meningitis is the most common intracranial complication of acute sinusitis.Orbital complication is the most common extracranial an overall complication of sinusitis