The Boundaries of the Cavities of the Skull

The boundaries of the cavities of the skull

(A brief summary)

Anterior cranial fossa

posterior surface of the squamous part of the frontal bone → posterior ridge of the lesser wing of the sphenoid bone, anterior clinoid process, optic canal and prechiasmatic groove

Middle cranial fossa

posterior ridge of the lesser wing of the sphenoid bone, anterior clinoid process, optic canal and prechiasmatic groove → superior margin of the petrous part of temporal bone and dorsum sellae

Posterior cranial fossa

superior margin of the petrous part of temporal bone and dorsum sellae → groove for transverse sinus, internal occipital protuberance

Orbit

superior: orbital part of frontal bone and lesser wing of sphenoid bone

lateral: orbital surface of zygomatic bone and orbital surface of greater wing of sphenoid bone

inferior: orbital surface of maxilla and orbital process of palatine bone

medial: frontal process of maxilla, lacrimal bone, orbital plate of ethmoidal bone and body of sphenoid bone

Nasal cavity

superior: nasal bone, nasal part of frontal bone, cribriform plate of ethmoid bone and body of sphenoid bone

lateral: nasal bone, frontal process and nasal surfaces of maxilla, lacrimal bone, nasal plate of ethmoid bone with superior and inferior nasal conchae, perpendicular plate of palatine bone, inferior nasal concha and medial plate of pterygoid process

inferior: palatine process of maxilla and horizontal plate of palatine bone

septum: perpendicular plate of ethmoid bone and vomer

Temporal fossa

superior and inferior temporal lines → the plane of infratemporal crest and zygomatic arch

Infratemporal fossa

anterior: maxillary tuber (approximately the same as the posterior surface of maxilla)

posterior: ramus of mandible

medial: lateral plate of pterygoid process

lateral: infratemporal crest and zygomatic arch

superior: infratemporal surface of greater wing of sphenoid bone

Pterygopalatine fossa

anterior: maxillary tuber (somewhere referred as posterior surface of maxilla)

posterior: maxillary surface of greater wing of sphenoid bone and anterior surface of the pterygoid process

medial: perpendicular plate of palatine bone

lateral: there is no lateral wall as it is completly occupied by the pterygomaxillary fissure

(Superior and inferior boundaries are also defined somewhere as the body of sphenoid bone and pyramidal process of palatine bone, respectively.)

Bony oral cavity

Only the hard palate can be defined, it consits of the palatine process of maxilla and horizontal process of palatine bone. The anterior and lateral walls are formed by the superior and inferior alveolar processes of maxilla and the teeth within them. The inferior and posterior wall is missing (are constituted by viscera).