Developmental Anatomy — MCQs

Q: Which paranasal sinuses are present at birth?

Ethmoid and maxillary. The development of paranasal sinuses is a high-yield topic in embryology. At birth, only the **maxillary** and **ethmoid** sinuses are present and pneumatized enough to be clinically identifiable, though they are rudimentary in size. 1. **Maxillary Sinus:** This is the first sinus to develop (around the 3rd month of fetal life). At birth, it is a small sac measuring approximately 7 x 4 x 4 mm. 2. **Ethmoid Sinus:** These air cells are present at birth and continue to enlarge during early childhood. **Analysis of Incorrect Options:** * **Frontal Sinus:** This sinus is **absent at birth**. It starts developing from the anterior ethmoidal cells around the age of 2 and is usually not radiologically visible until age 5–7. * **Sphenoid Sinus:** While a tiny evagination may exist at birth, it is effectively **absent/non-pneumatized**. It begins to invade the sphenoid bone around age 3 and reaches full development in adolescence. **High-Yield Clinical Pearls for NEET-PG:** * **Sequence of Development:** Maxillary → Ethmoid → Sphenoid → Frontal (Mnemonic: **M**y **E**xtra **S**pecial **F**riend). * **Radiology:** The frontal sinus is the last to appear on an X-ray. * **Clinical Correlation:** Because the frontal and sphenoid sinuses are absent at birth, sinusitis in infants typically only involves the ethmoid or maxillary sinuses. * **Growth:** The maxillary sinus shows a rapid growth spurt during the eruption of permanent teeth.

Practice by Chapter

Prenatal Development

Practice Questions

Postnatal Growth and Development

Practice Questions

Age-Related Anatomical Changes

Practice Questions

Developmental Abnormalities

Practice Questions

Principles of Teratology

Practice Questions

Developmental Basis of Congenital Anomalies

Practice Questions

Molecular Aspects of Development

Practice Questions

Genetic Factors in Developmental Anatomy

Practice Questions

Environmental Influences on Development

Practice Questions

Clinical Aspects of Developmental Anatomy

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free

Scan to download app