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),sphenoidðmoid. 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)
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.