Presentation ,Skull,By Dr Iram Iqbal
Transcript of Presentation ,Skull,By Dr Iram Iqbal
OsteologyCraniumDr Iram Iqbal
sequence• Skull,• Cranium• Anatomical position of skull • Norma verticalis• Norma Frontalis• Norma occipitalis• Norma Lateralis• Temporal, infra temporal, &Pterygopalatine fosses• Norma basali• Cranial fossae• Individual bones of skull• Muscle attachments
• Clinical note• conclusion
skull The skull is the bony skeletal of the
head. It shield the brain ,the organ of special sense and the cranial part of the respiratory and digestive system and providing attachments for many of the muscles of the head and neck.
Composed of 28 bones
Skull is divided in to 2 main parts– Calvaria (brain box)
– Fascial skeleton (rest of skull including mandible)
Cranium• Skull without mandible is called cranium it is divided into
– Neurocranium or cranial vault
• Enclosing brain ,meninges, csf
– Viscerocranium or fascial skeleton
• Houses the organs of special sense
Anatomical position of skull
Reid's base line• Reid's base line . It
is defined as a line drawn from the inferior margin of the orbit to the auricular point (center of the orifice of the external acoustic meatus) and extending backward to the center of the occipital bone
• skull is the Frankfurt plane , where the lower margins of the orbits and the upper borders of the ear canal s are all in a horizontal plane. ...also called eye-ear plane, Frankfort horizontal, Frankfort plane
NORMA VERTICALISNORMA VERTICALIS
• CORONAL SUTURE
• SAGITAL SUTURE
• LAMBDOID SUTURE
• BREGMA
• LAMBDA
NORMA FRONTALISNORMA FRONTALIS
• ORBITAL OPENING
• ANTERIOR NASAL APERTURE
ORBITORBIT
ROOF• Lecrimal fossa• Optic canal
MEDIAL WALL• Lecrimal groove• Forms the lateral wall of ethmoidal sinus• Lecrimal crest• Orbital plate of ethmoid
ORBITORBIT
FLOOR• Inferior orbital fissure• Infra orbital groove• Infra orbital foramen
LATERAL WALL•Formed by greater wing of sphenoid • frontal process of zeugmatic bone•Superior orbital fissure
ANTERIOR NASAL APERTUREANTERIOR NASAL APERTURE
NORMA OCCIPITALISNORMA OCCIPITALIS• External occipital protuberance• Inion • Superior nuchal line
NORMA LATERALISNORMA LATERALIS
TEMPORAL FOSSA• Boundaries• PterionZYGOMATIC ARCH• Formation • Roots of arch• Tubercle of zygoma• Supra mastoid crest
NORMA LATERALISNORMA LATERALISEXTERNALACOUSTICMEATUS• Upper margin
formed by squamous part of temporal bone
• Tympanic part• Supra meatal
triangle
MASTOID PART• Parietomastoid suture• Occipitomastoid suture• Asterion
• STYLOID PROCESS
• INFRATEMPORAL FOSSA
– AnteriorMaxilla
- MedialLateral Pterygoid
plate
INFRATEMPORAL FOSSAINFRATEMPORAL FOSSA
COMMUNICATIONS• Temporal fossa• Orbit • Pterygopalatine
fossaCONTENTS• Maxillary nerve• Maxillary artery• Pterygopalatine
ganglion
PTERYGOPALATINE FOSSAPTERYGOPALATINE FOSSA
COMMUNICATIONS– (laterally) Infratemporal
fossa– (Medial wall) Nasal cavity by
sphenopalatine foramen– (Above) Orbit by infraorbital
fissure
• Posterior wall has 3 openings
• (Upper) Foramen rotundum• (Below) Pterygoid cannal• (posterior wall) Sphenopalatine foramen
CONTENTS OF CONTENTS OF SUPERIOR SUPERIOR ORBITAL ORBITAL FISSUREFISSURE
• Branch of ophthalmic artery
• Occulomotor nerve• Trochlear nerve• Abducent nerve• Lecrimal nerve• Frontal nerve• Nasociliary nerve• Ophthalmic veins
• Infraorbital nerve &Vessels
• Zygomatic nerve• Branches from
Pterygopalatine ganglion
CONTENTS OF CONTENTS OF INFERIOR INFERIOR ORBITAL ORBITAL FISSUREFISSURE
NORMA BASALISNORMA BASALIS
EXTENT• From incisor teeth
back to superior nuchal lines
LATERRALLY• Teeth • Zygomatic arch• Mastoid process
ANTERIOR PART
MIDDLE PARTMIDDLE PART
POSTERIOR PARTPOSTERIOR PART
ANTERIOR CRANIAL FOSSSAANTERIOR CRANIAL FOSSSA
MIDDLE CRANIAL FOSSAMIDDLE CRANIAL FOSSA
POSTERIOR CRANIAL FOSSAPOSTERIOR CRANIAL FOSSA
Frontal bone• Half a shallow
irregular cap forming forehead
• It has– 3 parts
• Squamous (Main part)
• Nasal • Orbital • Zygomatic process
– 2 cavities• Frontal sinus
Ossification• It ossified in fibrous mesenchyme from 2
primary centers• Appear in 8th wk in utero near each frontal
tuber• Secondary center for nasal spine appear
about 10th year• At birth it has 2 halves• Median suture disappears at about 8th year• May persist as Metopic suture
Parietal bone
• 2 bones form most of cranial roof and side of the skull
• Irregular quadrilateral • & it has • 2 surfaces• 4 borders• 4 angles
Ossification• Each parietal bone ossified from 2
centres which appear in dense mesenchyme near the tuberosity,one above the other at about the 7th wk in utero.
• Angles are the last part to ossified & fontanelles occur at these sites
• At birth temporal lines are low down• Reach at their final position after the
eruption of molar teeth.
Occipital bone• Unpaired lies in
posterior part of skull• Pierced by foramen
magnum• It has 3 parts
– Squamous part– Basilar part– Condylar part
• Occipital condyles• Hypoglossal &post
Condylar canal. jugular process ,fossa &foramen, mastoid canaliculus ,canaliculus for tympanic n.
Occipital bone
Maxilla• 2nd Largest of facial bone• It has
– Body (4 surfaces)– Maxillary air sinus
• Ant surface• Infratemporal ( Jugal crest ,alveolar canals, pos sup
alveolar n&v)• Orbital (canalis sinuosus ,ant sup alveolar n)• Nasal
– 4 processes • frontal• zyomatic• Alveolar• palatine
Maxilla
Ossification• From a single center in a sheet of
mesenchyme.• Appear above the canine fossa at about
the 6th wk in utero and spread to rest of maxilla and its processes.
• The maxillary sinus appear as a shallow groove on the nasal aspect at about the 4th month in utero. (though small at birth)
• After birth it enlarge with growing maxilla• Fully developed following the eruption of
the permanent teeth.
Zygomatic bone• 2 processes . 5 borders• 3 surfaces . Whitnall,s
tubercle
OSSIFICATION• From one center• Appears in fibrous tissues about the
8th wk in utero
• Sphenoid• Unpaired ,it forms
middle part of base of skull
• Extend into Lateral wall of the vault & into orbit
• It has– Body(5 surfaces)– Rt & Lt greater
wings(3 surfaces)– Rt &Lt lesser wings– Rt & Lt Pterygoid
processes
sphenoid
Ossification• Until the 7th to 8th month in utero the
sphenoidal body has a presphenoidal part, ant to the tuberculum sellae with which the lesser wing was continuous .
• Postsphenoidal part consisting of sella turcica ,dorsum sallae, greater wing and Pterygoid process.
• Much of the bone preformed in cartilage.
• 6 ossification centres for presphenoidal
• 8 for postsphenoidal
Temporal bone
Temporal bone
Ethmoid bone
Inferior nasal concha &VOMER
Ossification• Ethmoidal bone ossifies in the
cartilaginous nasal capsule from 3 centres .1 for perpendicular plate,1 in each labyrinth. later 2 appear In the orbital plates b/e 4th and 5th month in utero.
• Inferior nasal concha ossifies from 1 centre which appear at about the 5th month in utero.
Palatine bone
ossification• Palatine bone ossifies in the
mesenchyme from 1 centre in the perpendicular plate that appear during 8th wk in utero
Clinical note• SCAPHOCEPHALY
• PLAGIOCEPHALY
• OXYCEPHALY
• TRIGONOCEPHALY
• PAN SYNOSTISIS
SCAPHOCEPHALY
Premature closure of sagittal suture.
PLAGIOCEPHALY
Premature closure of coronal suture on one side.
REFERANCESREFERANCES• GRAY’S ANATOMY 40th edition
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