Skull

D.Rania GabrD.Sama

Objectives

• Identify the different bones forming the skull with important foramina.

• Differentiate between the bony features of the skull of an adult and infant.

The Skull• It consists of flat and irregular bones• Divides into: Cranial bones which encase the brain Facial bones which form the bones of the face• The following must be identified: Nasion Inion Bregma Lambda External occipital protuberance Parietal eminence Zygomatic arch

• Cranial bones include: (Neurocranium) Frontal Ethmoid Sphenoidal Occipital

ParietalTemporal

• Facial bones include: (Viscerocranium)

MaxillaZygomaticNazalPalatine

Lacrimal Inferior concha

VomerMandible

The Skull

The Skull

• Frontal• Maxilla• Zygomatic• Nazal• Mandible• Lacrimal

The Skull

• Parietal• Temporal

SquamousMastoidStyloidTympanicPetrous

• SphenoidGreater wingLesser wingPterygoid processBody

• Occipital

The Skull

• Petrous part of temporal• Lesser wing of sphenoid• Body of sphenoid• Pterygoid process• Ethmoid bone

Crista galliCribriform platePerpendicular plate

• Vomer • Palatine bone

Cranial Fossa

• It is the cavity of the skull

• Divides into: Anterior cranial fossa Middle cranial fossa Posterior cranial fossa

Anterior Cranial Fossa

• Formed of: Orbital plate of frontal bone Cribriform plate of ethmoid Crista galli Lesser wing of sphenoid• Occupies: Frontal lobe of the cerebrum Optic nerves Olfactory bulb and tract

Middle Cranial Fossa

• Formed of: Greater wing of sphenoid Body of sphenoid Squamous part of temporal bone Anterior part of petrous bone• It occupies: Temporal lobe of the cerebrum

Posterior Cranial Fossa

• Formed of: Sphenoid part of clivus Posterior part of petrous bone Occipital bone• It shows the following land marks: Groove for transverse sinus Groove for segmoid sinus Internal occipital protuberance• It occupies: Cerebellum Brain stem

Base of The Skull

• Most of the bones are seen in other views

• Fracture base of the skull why?

Foramina of the Skull

• Foramina are found within the skull bones• They vary in size and shape• They transmit nerves, blood vessels and dura matter

Foramina of the Skull

Foramina of the Skull

• Supraorbital• Infraorbital• Mental

Sutures of the Skull

• Sutures are fibrous joints articulating the skull bones

• They include: Coronal Sagittal Lambdoid Pterion

Skull Fontanel

• Fontanels are spaces between some of the skull bones of infants

• They permit easy growth of the brain

• They permit overlapping of skull bones during labor

• They are anterior, posterior, anterolateral, and postero- lateral• They close later in life at 6-18 months

The Mandible

• It is a flat bone• Identify the following: Head(condylar process) Mandibular notch Coronoid process Ramus Angle Body Mylohyoid line Submandibular fossa Digastric fossa Mandibular foramen Mental foramen