Table 1.
Summary of cranial fossae features and findings in the T18 fetus at 28 weeks
| Cranial fossa | T18 Cranial fossae shifted anteriorly |
|---|---|
| Anterior cranial fossa | |
| Sphenoid bone | |
| Lesser wing | Absent on right side, reduced on left side |
| Ethmoid bone | |
| Crista galli | Absent |
| Cribriform plate | Absent |
| Orbital part of the frontal bone (forms roof of orbit) | Absent |
| Middle cranial fossa | |
| Sphenoid bone | |
| Superior orbital fissure | Present on left side, absent on right |
| Hypophyseal fossa | Cartilaginous, incomplete |
| Anterior clinoid process | Highly reduced |
| Optic canal | Singular, centrally located |
| Posterior clinoid process | Highly reduced |
| Dorsum sellae | Diminutive |
| Greater wing of sphenoid bone | |
| Foramen rotundum | Size reduced |
| Foramen ovale | Size reduced |
| Temporal bone | |
| Squamous part | Underdeveloped, anteriorly located |
| Superior border of petrous part | Malformed, highly enlarged |
| Trigeminal ganglion | Highly reduced |
| Internal carotid artery | Not observed in gross view |
| Internal acoustic meatus | Enlarged, bony protuberance |
All structures were present in the control fetus at 29 weeks.