Advanced Ethmoid Bone Quiz

Q1. Why can a fracture of the cribriform plate cause anosmia?

• The optic chiasm lies inside the cribriform foramina
• Olfactory nerve filaments passing through the plate can be torn
• The facial nerve is severed within the plate
• The vagus nerve supplies the olfactory epithelium

Q2. Why can a cribriform plate fracture cause cerebrospinal fluid rhinorrhea?

• The nasolacrimal duct opens into the cranial cavity
• The ethmoidal cells produce cerebrospinal fluid
• A meningeal tear can connect the subarachnoid space with the nasal cavity
• The carotid canal normally drains into the nose

Q3. Why can ethmoidal sinus infection spread into the orbit relatively easily?

• The orbital floor is absent beside the ethmoid
• The ethmoid contains the lacrimal gland
• The lamina papyracea is a very thin partition between ethmoidal cells and the orbit
• The optic canal opens directly into every ethmoidal cell

Q4. Why is the crista galli important in intracranial dural anatomy?

• It forms the jugular foramen
• It anchors the anterior falx cerebri
• It anchors the posterior tentorium to the mandible
• It contains the cavernous sinus

Q5. Why can injury near the anterior ethmoidal foramen cause both neural and vascular damage?

• The vagus nerve and sigmoid sinus share the foramen
• The anterior ethmoidal nerve and artery pass together through the foramen
• The facial nerve and internal carotid artery share the foramen
• The hypoglossal nerve and vertebral artery share the foramen

Q6. Why is the ethmoid particularly important to both cranial and nasal anatomy?

• It contributes only to the temporomandibular joint
• It contributes to the cranial floor, nasal cavity, septum, and orbit
• It forms only the posterior cranial vault
• It is confined entirely to the oral cavity

Q7. Why can disruption of the lamina papyracea during endoscopic sinus surgery endanger orbital contents?

• It forms the lateral wall of the maxillary sinus only
• It is a thin medial orbital wall directly adjacent to orbital contents
• It contains the mandibular canal
• It is separated from the orbit by the parotid gland

Q8. Why are the ethmoidal air cells clinically complex compared with a single large sinus cavity?

• They drain exclusively into the inferior meatus
• They have no relationship to the orbit
• They form multiple variable cell groups with distinct drainage routes
• They are a single unpartitioned cavity

Q9. Why is the perpendicular plate vulnerable to contributing to nasal septal deviation after trauma?

• It is embedded within the tongue
• It forms the mandibular symphysis
• It forms the posterior wall of the external acoustic meatus
• It is a thin structural component of the bony nasal septum

Q10. Which statement best integrates the anatomy of the ethmoid bone?

• It is a paired bone confined to the lateral cranial vault
• It forms only the hard palate and upper teeth
• It connects cranial, nasal, sinus, septal, and orbital anatomy and transmits important neural and vascular structures
• It is a dense posterior skull bone containing the foramen magnum