SKULL
The cranium (skull)
can be subdivided
into:
•an upper part (the
calvaria), which
surrounds the cranial
cavity containing the
brain;
•a lower anterior partthe facial skeleton
(viscerocranium).
The bones
forming the
calvaria are:
1.paired temporal
2. paired parietal
3. unpaired frontal
4. sphenoid
5.Ethmoid
6.occipital bones.
1.
2.
3.
4.
5.
6.
7.
The bones
forming the
facial skeleton
are:
paired nasal
maxillae
zygomatic
lacrimal
inferior nasal
conchae,
palatine bones
unpaired vomer.
Superior view of the skull
Norma verticalis
Newborn
skull
Anterior view
Norma frontalis
Bones:
Frontal
2 Nasal
2 Maxillary
2
zygomatic
Openings
2 Orbital
piriform
Sutures
Internasal
Frontonasal
Frontozygomatic
intermaxillary
Features
Nasion
Glabella
Superciliary
arches
Anterior
nasal spine
foramena
Supraorbital
Infraorbital
Zygomaticofascial
Lateral view
Norma lateralis
bones forming
the facial
skeleton: the
nasal, maxilla,
and zygomatic
bones
bones
forming the
lateral
portion of the
calvaria
include the
frontal,
parietal,
occipital,
sphenoid,
temporal
bones
Sutures:
Coronal
Sphenoparietal
Sphenosquamous
Squamous
Parietomastoid
Occipitomastoid
Lambdoid
The junction
where the
frontal, parietal,
sphenoid, and
temporal bones
are in close
proximity is the
pterion
Temporal bone :
squamous part
tympanic part
petrous part
mastoid part
Features
External auditory
meatus
Temporal line
Supramastoid crest
Temporal fossa
Pterion
Suprameatal
triangle
Styloid process
Asterion
Mastoid foramen
Lateral view
Posterior view
Norma occipitalis
Bones
2 Parietal
Squamous occipital
2 Mastoid temporal
Sutures
Sagittal
Lambdoid
Parietomastoid
Occipitomastoid
Features
Lambda
Asterion
External
occipital
protuberance
Inion
Superior
nuchal lines
Highest
nuchal lines
The end
Inferior view
Norma basalis externa
The base of the
skull is divided
into:
•anterior part
•middle part
•posterior part
By 2 lines
•hard palate
• the anterior
margin of the
foramen
magnum
The hard palate is composed of:
• palatine processes of each maxilla
• horizontal plates of each palatine
bone
Sutures: cruciform suture
intermaxillary suture,
palatomaxillary suture,
interpalatine suture
Features
•
•
•
incisive fossa and incisive foramina
greater palatine foramina which lead to greater
palatine canals;
• pyramidal process of palatine bone,
lesser palatine foramina
• posterior nasal spine
Middle part
The middle part of the base of the skull is
complex:
• forming the anterior half are the vomer and
sphenoid bones;
• forming the posterior half are the occipital
and paired temporal bones
The anterior half of the middle part
• Anteriorly, the small vomer is in the
midline, resting on the sphenoid bone
• The sphenoid bone is made up of a
centrally placed body, paired greater and
lesser wings projecting laterally from the
body, and two downward projecting
pterygoid processes immediately lateral
to each choana
• Pterygoid processes consists of a narrow
medial plate and broader lateral plate
separated by the pterygoid fossa
The anterior half of the middle part
• Each medial plate of the pterygoid process
ends inferiorly with a hook-like projection,
the pterygoid hamulus, and divides
superiorly to form the small, shallow
scaphoid fossa
• Important features visible on the surface of
the greater wing in an inferior view of the
skull are the foramen ovale and the
foramen spinosum on the posterolateral
border extending outward from the upper
end of the lateral plate of the pterygoid
process
The posterior half of the middle part
• In the posterior half of the middle part of
the base of the skull are the occipital bone
and the paired temporal bones
• The parts of the occipital bone are the
squamous part, which is posterior to the
foramen magnum, the lateral parts, which
are lateral to the foramen magnum, and
the basilar part, which is anterior to the
foramen magnum
The posterior half of the middle part
• On each anterolateral border of the foramen
magnum are the rounded occipital condyles
• Posterior to each condyle is a depression (the
condylar fossa) containing a condylar canal,
and anterior and superior to each condyle is the
large hypoglossal canal.
• Lateral to each hypoglossal canal is a large,
irregular jugular foramen formed by opposition
of the jugular notch of the occipital bone and
jugular notch of the temporal bone.
• Anteromedial to the mastoid process is the
needle-shaped styloid process. between the
styloid process and the mastoid process is the
stylomastoid foramen
Bony mandible
Mandible
• The mandible is the bone of the lower jaw
• It consists of a body of right and left parts,
which are fused anteriorly in the midline
(mandibular symphysis).
• The upper surface of the body of mandible
bears the alveolar arch, which anchors the
lower teeth, and on its external surface on
each side is a small mental foramen.
Lateral view
Mandible
• the superior and inferior mental spines
(superior and inferior genial spines)
• the mylohyoid line
• Above the anterior one-third of the mylohyoid
line is a shallow depression (the sublingual
fossa), and below the posterior two-thirds of the
mylohyoid line is another depression (the
submandibular fossa).
• The ramus of mandible, one on each side, is
quadrangular shaped. On the medial surface of
the ramus is a large mandibular foramen for
transmission of the inferior alveolar nerve and
vessels.
Medial view
Superior view
Hyoid bone
• The hyoid bone is a small U-shaped bone in the
neck between the larynx and the mandible.
• It has an anterior body of hyoid bone and two
large greater horns, one on each side, which
project posteriorly and superiorly from the body
• There are two small conical lesser horns on the
superior surface where the greater horns join
with the body.
• The stylohyoid ligaments attach to the apices of
the lesser horns.
Superior view
Lateral view
Cervical vertebrae
Cervical vertebrae
• The seven cervical vertebrae form the bony
framework of the neck.
Cervical vertebrae are characterized by:
• small bodies;
• bifid spinous processes;
• transverse processes that contain a foramen
(foramen transversarium).
• The typical transverse process of a cervical
vertebra also has anterior and posterior
tubercles for muscle attachment.
Typical features
Typical cervical vertebra
Atlas
• Vertebra CI (the atlas) lacks a vertebral body.
• When viewed from above, the atlas is ring-shaped and
composed of two lateral masses interconnected by an
anterior arch and a posterior arch.
• Each lateral mass articulates above with an occipital
condyle of the skull and below with the superior articular
process of vertebra CII (the axis).
• The superior articular surfaces are bean shaped and
concave, whereas the inferior articular surfaces are
almost circular and flat.
• The atlanto-occipital joint allows the head to nod up
and down on the vertebral column.
• The posterior surface of the anterior arch has an articular
facet for the dens
• The dens is held in position by a strong transverse
ligament of atlas
atlas
Axis
• The axis is characterized by the large tooth-like
dens, which extends superiorly from the
vertebral body
• The anterior surface of the dens has an oval
facet for articulation with the anterior arch of the
atlas.
• The two superolateral surfaces of the dens
possess circular impressions that serve as
attachment sites for strong alar ligaments, one
on each side, which connect the dens to the
medial surfaces of the occipital condyles. These
alar ligaments check excessive rotation of the
head and atlas relative to the axis.
Axis-vertebra CII (superior view)
Axis
Atlas and axis (anterolateral view)
Atlanto-occipital joint (posterior view)