Anterior Cranial Fossa Flashcards

Examine the anterior cranial fossa, including its bony boundaries, frontal lobe relationships, ethmoidal landmarks, foramina, and clinical anatomy.

Card 1 of 28Question

What is the anterior cranial fossa?

The most anterior and shallowest depression of the internal cranial base.

In This Section

1. What is the anterior cranial fossa?

The most anterior and shallowest depression of the internal cranial base.

2. Which bones form the anterior cranial fossa?

The frontal, ethmoid, and sphenoid bones.

3. Which parts of the brain occupy the anterior cranial fossa?

The frontal lobes of the cerebral hemispheres.

4. What forms the anterior and lateral floor of the anterior cranial fossa?

The orbital plates of the frontal bone.

5. Which part of the ethmoid bone forms the central floor of the anterior cranial fossa?

The cribriform plate.

6. Which parts of the sphenoid bone contribute to the anterior cranial fossa floor?

The lesser wings and the anterior superior surface of the sphenoid body.

7. What forms the posterior boundary of the anterior cranial fossa?

The posterior borders of the sphenoid lesser wings, anterior clinoid processes, and sphenoidal limbus.

8. Which cranial fossa lies immediately posterior to the anterior cranial fossa?

The middle cranial fossa.

9. What is the cribriform plate?

A thin, perforated horizontal plate of the ethmoid bone forming part of the nasal cavity roof.

10. Which nerve fibers traverse the foramina of the cribriform plate?

Olfactory nerve fibers (cranial nerve I).

11. Which structures rest on the superior surface of the cribriform plate?

The olfactory bulbs.

12. What is the crista galli?

A vertical midline projection of the ethmoid bone extending superiorly from the cribriform plate.

13. Which dural fold attaches to the crista galli?

The falx cerebri.

14. What is the frontal crest?

A midline ridge on the internal surface of the frontal bone that provides anterior attachment for the falx cerebri.

15. What is the foramen cecum?

A small midline opening between the frontal bone and ethmoid bone, anterior to the crista galli.

16. Which vessel may traverse a patent foramen cecum?

An emissary vein connecting nasal veins with the superior sagittal sinus.

17. Which structure passes through the anterior ethmoidal foramen?

The anterior ethmoidal nerve, artery, and vein.

18. Which structures traverse the posterior ethmoidal foramen?

The posterior ethmoidal nerve, artery, and vein.

19. Which bony structures separate the anterior cranial fossa from the orbits?

The orbital plates of the frontal bone.

20. Which nasal structures lie immediately inferior to the cribriform plate?

The superior portions of the nasal cavities, including the olfactory regions.

21. What are the anterior clinoid processes?

Medially directed projections from the posterior ends of the sphenoid lesser wings.

22. Which dural structure attaches to the anterior clinoid processes?

The free and attached margins of the tentorium cerebelli.

23. What are the cerebral impressions on the floor of the anterior cranial fossa?

Shallow depressions produced by the inferior surfaces of the frontal lobes.

24. Why can fractures of the cribriform plate cause anosmia?

They may tear olfactory nerve fibers as they pass between the nasal mucosa and olfactory bulbs.

25. What causes cerebrospinal fluid rhinorrhea after an anterior cranial fossa fracture?

A defect in the skull base and meninges allows cerebrospinal fluid to leak into the nasal cavity.

26. What are raccoon eyes in the context of an anterior skull base fracture?

Periorbital ecchymosis caused by blood tracking into the tissues surrounding the eyes.

27. Why can a defect in the anterior cranial fossa floor increase the risk of meningitis?

It may create a communication between the nasal cavities and intracranial space, allowing microorganisms to enter.

28. What is an anterior skull base encephalocele?

Herniation of intracranial contents through a defect in the anterior cranial base, sometimes extending into the nasal cavity.