Anterior Cranial Fossa : Mnemonic

Boundaries

1. Anterior and Lateral: Frontal bone (inner surface)
2. Posterior:
   • Medial: Sphenoid (limbus)
   • Lateral: Sphenoid (lesser wing)
3. Floor: Frontal bone, Ethmoid bone, Sphenoid bone (lesser wing and anterior aspect of body)

Contents

Mnemonic: Remember 6 ‘C’

1. Frontal Crest: Site of attachment of falx cerebri

2. Foramen Cecum (Between frontal crest and crista galli): Site of communication between the draining veins of nasal cavity and the superior sagittal sinus

3. Crista galli: Site of attachment for falx cerebri

4. Cribiform plate: Supports Olfactory bulb and Olfactory tract runs through it

• 2 foramina lateral to the olfactory bulb:
  • Anterior ethmoidal foramen: transmits anterior ethmoidal artery, nerve and vein
  • Posterior ethmoidal foramen: transmits posterior ethmoidal artery, nerve and vein

5. Anterior Clinoid process (formed by lesser wing of sphenoid): Important landmark for the optic nerve and supracavernous Internal Carotid Artery (ICA)

6. Chiasmatic sulcus: for optic chiasm

Clinical considerations

Fractures of the anterior cranial fossa:

1. Bleeding: from anterior meningeal vessels when dura is torn
2. Anosmia: injury to olfactory nerve fibers which run through the cribiform plate
3. CSF rhinorrhea: tear in meningeal coverings leading to leakage of CSF into nasal cavity

Ophthalmic artery:

• Branch of supraclinoid portion of ICA
• Origin is medial to anterior clinoid process and below the optic nerve
• At the level of optic canal, the artery has passed to a position lateral to the nerve
• This anatomical fact must be kept in mind during the opening of the falciform ligament to avoid an iatrogenic lesion of the artery