Skull

BY: DR.Yahya Alfarra

Skull • Defenition:it is the skeleton of the head

* The skull is composed of several separate bones united at immobile joints called sutures (line of fusion) note??

* Mandible is united to skull by mobile T.M.J Parts of the skull: The skull is divided into 2 parts 1- cranium OR skull cap 2- Facial skeleton.

1- The cranium(skull cap):* The upper& post. Part which encloses the brain.• It consists of the following bones:

Frontal,parietal(2),occipital,temporal(2),sphenoid&ethmoid.

2- Facial bones:* it’s the ant. Part of skull which includes: A- upper fixed part. B- lower movable part(mandible)

* It consists of the following bones: Zygoamtic bone,maxillae,nasal,lacrimal,vomer,palatine,inf.

Conchae,mandible Total : 22 bones

• For convinous of the description,the skull is

described from various aspect: 1- from sup. Aspect(or norma verticalis) 2- from ant. Aspect(or norma frontalis) 3- from lat. Aspect(or norma lateralis) 4- from post. Aspect(or norma

occipitalis) 5- from inf. Aspect(or norma basalis)

1 -from sup. Aspect(or norma verticalis)

• Now we are going to describe sup. Aspect

of skull or norma verticalis:

This superior aspect shows :

1- frontal bone- anteriorly

2- occipital bone-posteriorly

3- 2 parietal bone- inbetween(on the side)

Coronal suture

Lambdoidal suture

2 -Ant. Aspect of skull(norma frontalis)

• The ant. Aspect shows: - forehead - orbital cavity- Nasal cavity seperated by nasal

septum- Upper & lower jaw

A- Forehead Anatomical features:• superciliary arches which are more prominent in

male than female.• nasofrontal suture • nasion• glabella• Note: in some cases the 2 halves of frontal bone

persist in adult and called metapoic suture.

B- Orbital cavity it’s pyramidal in shape having abase open into

face & apex which it opens into cranial cavity.

The base of orbit have 4 margins

1- sup.

2- inf.

3-medial

4- lateral

• sup. Orbital foramen which transmit supraorbital nerves&vesseles.

• the supratrochlear notch which transmit supraorbital nerves&vesseles.

• The inf. Orbital margin , it’s formed by maxilla medially& zygomatic bone laterally

• infraorbital foramen which transmit infraorbital N.&V.

• lacrimal fossa• Note: the cavity of orbit has a roof , floor ,medial

wall & lateral wall.• Optic canal

• Inf. Orbital fissure communicate orbit with both infratemporal fossa & pterygopalatine fossa , it transmits continuation max. N. which is called infratemporal N. & branch of maxillary A. which is called infratemporal A.

C- Nasal bone:

* 2 nasal bones seperated by nasal septum

*This is ant. Nasal spine

*This is canine eminence : projection produced by root of canine tooth

* Canine fossa :

* Incissive fossa :

D- Maxilla *It’s enclose with maxillary air sinus to form upper jaw*The process with carry teeth it called alv. Process *The process which formed part of hard palate is called

palatine process.

Zygoamtic bone:It’s articulate with zygomatic process of temporal bone to

form zygomatic arch which lies in lateral aspect of skull.