Cranial cavity (Norma basalis interna)

https://drive.google.com/file/d/1LELe... This document outlines the features and foramina of the three parts of the cranial cavity (Norma Basalis Interna): the anterior, middle, and posterior cranial fossae. 1. Anterior Cranial Fossa Bones Forming the Floor: Orbital plates of the frontal bone and the ethmoid bone. Ethmoid Bone Features (Anteriorly): Cribriform plate (a perforated bony plate) and the Crista galli (a median bony projection). Posterior Structures: Jugum sphenoidale (anterior part of the body of the sphenoid) and the lesser wing of the sphenoid, which ends medially in the anterior clinoid process. Foramina: Foramen caecum (between crista galli and frontal crest), foramina of the cribriform plate, and anterior and posterior ethmoidal foramina. 2. Middle Cranial Fossa Median Part (Formed by Body of Sphenoid): Includes the optic groove (leading to the optic canal) and the Sella turcica, which contains the Tuberculum sellae, Hypophyseal (pituitary) fossa, and Dorsum sellae. The Dorsum sellae's expanded lateral end is the posterior clinoid process. Lateral Part (On Either Side): Formed by the greater wing of the sphenoid and the petrous temporal bone. Greater Wing Foramina: Superior orbital fissure, foramen rotundum, foramen ovale, and foramen spinosum. Petrous Temporal Bone Features: Foramen lacerum, Trigeminal impression, Arcuate eminence, Tegmen tympani, and greater and lesser petrosal hiatuses and grooves. 3. Posterior Cranial Fossa Anterior to Foramen Magnum: Body of sphenoid and basilar part of occipital bone fuse to form the clivus. Posterior to Foramen Magnum: Internal occipital protuberance and a cruciate ridge formed by the Internal occipital crest (below), Superior sagittal sulcus (above), and Transverse sulcus (on each side). Sulci on Either Side of Foramen Magnum: Sigmoid, superior petrosal, and inferior petrosal. Foramina: Foramen magnum, internal auditory meatus, jugular foramen, anterior condylar canal, posterior condylar canal, and mastoid foramen.