BONES OF THE SKULL

 

 

NEUROCRANIUM                                                              VISCEROCRANIUM

 

FRONTAL (1)                                                             NASAL (2)

PARIETAL (2)                                                                        ZYGOMATIC (2)

TEMPORAL (2)                                                                                  Frontal Process

Squamous Part                                                             Temporal Process

Mastoid Process                                                                       Maxillary Process

Zygomatic Process                                                       MAXILLA (2)

Petrous Part                                                                             Zygomatic Process

Frontal Process

OCCIPITAL (1)                                                                                  Alveolar Process

SPHENOID (1)                                                                                   Anterior Nasal Spine Greater Wing                                                                            Palatine Process

Lesser Wing                                                                 PALATINE (2)

Medial and Lateral Pterygoid Plates                                          Perpendicular Plate

Sella Turcica                                                                             Horizontal Plate

 

ETHMOID (1)                                                             INFERIOR CONCHA (2)

Crista Galli                                                                   VOMER (1)

Cribriform Plate                                                            MANDIBLE (1)

Perpendicular Plate                                                                   Head

Lamina Papyracea                                                                    Notch

Coronoid Process

Ramus

Body

Mental Eminence

 

 

 

                                           FEATURES OF THE CRANIAL CAVITY

 

ANTERIOR FOSSA:  formed by the orbital plates of the frontal bone, the cribriform plate of the ethmoid bone and the lesser wings of the sphenoid bone

 

FORAMEN CECUM - transmits emissary vein that connects the nasal veins and the superior sagittal sinus

 

CRISTA GALLI - anterior attachment of the falx cerebri

 

CRIBRIFORM PLATE - olfactory nerve (I), anterior ethmoidal vessels and nerves

 

POSTERIOR ETHMOIDAL FORAMEN - transmits posterior ethmoidal vessels and nerves from the orbit to the anterior cranial fossa

 

MIDDLE FOSSA:  bounded by the lesser wing of the sphenoid bone and the anterior clinoid processes anteriorly.  The superior ridges of the petrous portion of the temporal bones form the posterior boundary.  The middle fossa includes the greater wing of the sphenoid bone and the squamous portion of the temporal bone.

 

CHIASMATIC GROOVE - connects the optic foramina and contains the optic chiasma

 

HYPOPHYSEAL FOSSA - contains the diaphragma selle, which is a special dural fold surrounding the pituitary gland

 

SUPERIOR ORBITAL FISSURE - connects the cranial cavity with the orbit.  It transmits the   oculomotor n. (III), the trochlear n. (IV), the ophthalmic division of the trigeminal n. (V1), abducens n. (VI), sympathetic fibers from the cavernous plexus and the ophthalmic veins.

 

DORSUM SELLAE - together with the posterior clinoid processes it forms the attachment for the tentorium cerebelli

 

CAROTID GROOVE - carries the internal carotid artery as it enters the cranial cavity.  It also lodges the cavernous sinus.

 

FORAMEN ROTUNDUM - transmits the maxillary n.  (V2)

 

FORAMEN OVALE  - transmits the mandibular n. (V3) and the accessory meningeal artery, which is a branch of the maxillary artery.

 

FORAMEN SPINOSUM - carries the middle meningeal artery

 

CAROTID CANAL - the entrance for the carotid artery

 

DEPRESSION FOR THE SEMILUNAR GANGLION - on petrous part of the temporal bone

 

 

POSTERIOR FOSSA: formed by the occipital bone, the petrous and mastoid portions of the temporal bones and the inferior portion of the parietal bone

 

FORAMEN MAGNUM - spinal cord, vertebral vessels, spinal accessory n. (XI)

 

HYPOGLOSSAL CANAL - hypoglossal n. (XII)

 

PETRO-OCCIPITAL FISSURE - for the inferior petrosal sinus which connects the cavernous sinus to the sigmoid sinus at the jugular foramen

 

JUGULAR FORAMEN - jugular vein leaves the cranial cavity with glossopharyngeal n. (IX), vagus n. (X) and accessory n. (XI)

 

INTERNAL ACOUSTIC MEATUS - transmits the facial n. (VII), vestibulocochlear n. (VIII) and the labyrinthine artery (from basilar art, to supply the inner ear)

CONDYLOID CANAL - emissary veins connect the lower sigmoid sinus with veins in the  suboccipital triangle (occipital, deep cervical or vertebral veins)

 

MASTOID FORAMEN - contains the mastoid emissary veins which connect the posterior auricular vein with the sigmoid sinus