Head

A The A nterior, M iddle and P osterior cranial fossae from above An illustration of the inferior view of the human skull. The skull is labeled with numbers and letters to indicate different anatomical features. https://www.w3.org/1999/xlink" content-type="colour" xlink:href=" https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003679868/1695039f-b7ac-4492-8001-b65743b8361c/content/fig101_10_1_C.jpg "/> ➜ Notes This illustrates the three cranial fossae on the interior aspect of the skull base. The A nterior fossa is limited posteriorly by the posterior edge of the lesser wing of the sphenoid ( 7 ). The M iddle cranial fossa extends from here to the superior border of the petrous part of the temporal bone ( 14 ), while the P osterior fossa, the largest and deepest of the three, extends posteriorly to the junction of the basilar and squamous parts of the occipital bone, marked by the groove formed by the transverse venous sinus ( 35 ). Note that a fracture through the orbital part of the frontal bone ( 6 ) may implicate the cribriform plate ( 5 ). If the overlying dura is torn, this will allow cerebrospinal fluid (CSF) to escape through the nose (CSF rhinorrhoea) and provide a pathway for bacteria to pass from the nasal cavity to the meninges (meningitis).