Download osteology of head and neck

OSTEOLOGY OF HEAD AND
NECK
THE SKULL
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Skeleton of the head is
called the Skull.
Can be divided into two
main parts:
The calvaria or brain box
,upper part of the
cranium which encloses
the brain.
fascial skeleton
constitutes the rest of the
skull and includes the
mandible.
Bones of the skull
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22 bones
Calvaria is composed of 8 bones:
Paired:
parietal
temporal
unpaired
Frontal
Occipital
Sphenoid
ethmoid
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The facial skeleton is composed of 14 bones:
Paired:
Maxilla
Zygomatic
Nasal
Lacrimal
Palatine
Inferior nasal concha
unpaired:
mandible
vomer
Joints of skull
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Most of the joints of the skull are
immovable and fibrous in type called
SUTURES.
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1.
2.
3.
4.
5.
The skull can be studied externally in
different ways:
Superior view or Norma verticalis
Posterior view or Norma occipitalis
Anterior view or Norma frontalis
Lateral view or Norma lateralis
Inferior view or Norma basalis
Norma verticalis
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Usually oval in shape
Wider posteriorly than anteriorly
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1.
2.
3.
Bones seen:
Upper part of the frontal bone.
Uppermost part of the occipital bone
posteriorly.
Parietal bone on each side.
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1.
2.
SUTURES:
Coronal suture:placed
between the frontal
bone and the two
parietal bones.
The suture crosses the
cranial vault from side
to side and runs
downwards and
forwards .
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SAGITTAL SUTURE:
Placed in the median plane between the
two parietal bones.
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LAMBDOID SUTURE:
Lies posteriorly between the occipital and
the two parietal bones
Runs downwards and forwards across the
cranial vault
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METOPIC SUTURE: Occasionally present in
about 3-8% individuals .
Lies in the median plane
Separates the two halves of the frontal
bone.
Named features
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Vertex: highest point on the sagittal
suture.
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vault:arched roof for the dome of the
skull
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Bregma :meeting point between the
coronal and sagittal sutures.
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In the fetal skull, this is the site of a
membranous gap called the anterior
fontanelle.
Closes at eighteen months of age.
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The lambda is the meeting point between
the sagittal and lambdoid suture.
In the fetal skull this is the site of
postreior fontanelle which closes at two or
three months of age.
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The parietal tuber :area of maximum
convexity of the parietal bone.
Common site of fracture of the skull`
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The parietal foramen :one
on each side.
Pierces the parietal bone
near it’s upper border,2.5
to 4 cm in front of the
lambda.
Transmits an emissary
vein from the scalp to the
superior sagittal sinus.
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The OBELION is the point on the sagittal
suture between the two parietal foramina.
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The TEMPORAL lines :begin at the
zygomatic process of the frontal bone
Arch backwards and upwards and cross
the frontal bone,the coronal suture and
the parietal bone
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Two lines are present over the parietal
bone:
Superior
inferior
NORMA OCCIPITALIS
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1.
2.
3.
Convex upwards and on
each side , and is
flattened below.
Bones seen:
Posterior part of the
parietal bones,above
Upper part of the
squamous part of the
occipital bone below.
Mastoid part of the
temporal bone ,on each
side.
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Sutures:
Lambdoid suture lies
between the occipital
bone and the two
parietal bones
Occipitomastoid
suture lies between
the occipital bone and
the mastoid part of
the temporal bone.
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Parietomastoid suture
lies between the
parietal bone and the
mastoid part of
temporal bone.
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Other features:
Lambda
Parietal formina
Obelion
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The external occipital protuberance
:median prominence in the lower part.
Marks the junction of head and neck.
The most prominent part is known as
INION.
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The SUPERIOR
NUCHAL LINES are
curved bony ridges
passing laterally from
the protuberance
Mark the junction of
head and neck.
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HIGHEST NUCHAL LINES
are not always present.
Curved bony ridges about
1 cm above the superior
nuchal lines.
Begin from the upper part
of the external occipital
protuberance.
More arched than the
superior nuchal line.
The OCCIPITAL POINT
is a median point ,a
little above the inion.
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MASTOID FORAMEN
located on the mastoid
part of the temporal bone
at or near the
occipitomastoid suture.
Transmits an emissary
vein and the meningeal
branch of the occipital
artery
NORMA FRONTALIS
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Roughly oval in outline
Wider above than below
Bones
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The FRONTAL bone forms
the fore head
Upper part smooth and
convex
Lower part
irregular,inturrupted by
the :
orbits
anterior bony aperture
of the nose.
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The RIGHT and LEFT MAXILLAE form the
upper jaw.
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The RIGHT and LEFT NASAL bones form
the bridge of the nose.
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The ZYGOMATIC bones form the bony
prominence of the superolateral part of
the cheeks.
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The MANDIBLE forms the lower jaw.
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Can be studied as:
Frontal region
Orbital opening
Anterior piriform –shaped bony aperture
of the nose
Lower part of the face.
Frontal region
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SUPERCILIARY
ARCH:rounded curved
elevation just above
the medial part of
each orbit.
Overlies the frontal
sinus
Better marked in
males than females.
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The GLABELLA :median elevation
connecting the two superciliary arches.
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The NASION is a median point at the root
of the nose where the internasal suture
meets with the frontonasal suture.
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The FRONTAL TUBER or EMINENCE:low
rounded elevation above the superciliary
arch.
Orbital opening
Quadrangular in shape
 Bounded by following 4
margins:
1.supraorbital
margin:formed by the
frontal bone.
At the junction of it’s lateral
two –thirds and it’s
medial one –third supra
orbital notch or foramen
is present.
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2.Infra orbital margin:formed by the
zygomatic bone laterally
maxilla medially
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3. medial orbital margin is ill-defined.
Formed by:
Frontal bone above
Lacrimal crest of the frontal process of the
maxilla below.
4. Lateral orbital margin :formed mostly by
frontal process of zygomatic bone
Completed above by the zygomatic process
of frontal bone.
Frontozygomatic suture lies at their union.
ANTERIOR BONY APERTURE OF
THE NOSE
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Pear shaped.
Wide below and narrow
above.
BOUNDARIES:
Above :by the lower
border of the nasal
bones.
below:by the nasal notch
of the body of the maxilla
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The two nasal bones form the bridge of
the nose.
The nasal cavity is divided into two by the
bony nasal septum which is largely formed
by the VOMER.
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The superior and
middle conchae are
shelves of bone that
project into the nasal
cavity from the
ETHMOID on each
side.
Inferior conchae are
separate bones.
LOWER PART OF THE FACE
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MAXILLA:the anterior surface
of the body of the maxilla
presents:
a) the nasal notch medially
b) the anterior nasal spine
c) the infraorbital foramen
d)the incisive fossa above the
incisors
e)the canine fossa lateral to
the canine eminence.
Processes of maxilla
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a)frontal process
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b)zygomatic process
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c)alveolar process
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Zygomatic bone:
Forms the prominence of the cheek
The zygomaticofacial foramen is also seen
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Mandible:forms the
lower jaw
Upper border or lower
arch lodges the lower
teeth.
Lower border or base
is rounded.
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The middle point of the base is called the
mental point or GNATHION.
Anterior surface of the
body of the mandible
presents :
a) the symphysis
menti,mental
protuberance and the
mental tubercles
anteriorly.
b) Mental foramen
c) Oblique line
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Sutures of norma frontalis
1.
2.
3.
4.
5.
6.
7.
8.
Internasal
Frontonasal
Nasomaxillary
Lacrimomaxillary
Frontomaxillary
Intermaxillary
Zygomaticomaxillary
zygomaticofrontal
NORMA LATERALIS
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1.
2.
3.
4.
5.
6.
7.
8.
9.
Bones:
Frontal
Parietal
Occipital
Temporal
Sphenoid
Zygomatic
Mandible
Maxilla
nasal
features
1.
2.
3.
4.
5.
6.
7.
8.
Temporal lines
Zygomatic arch
External acoustic
meatus
Mastoid part of temporal
bone.
Styloid process
Temporal fossa
Infratemporal fossa
Pterygopalatine fossa