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Axial Skeleton:
The Skull
Slides by Vince Austin;
figures from Marieb & Hoehn 8th ed.;
modifications and some slides by W. Rose
Portions copyright Pearson Education
The Axial Skeleton
Eighty bones segregated into three regions
– Skull
– Vertebral column
– Bony thorax
Figure 7.1 The human skeleton.
Skull
Thoracic cage
(ribs and
sternum)
Vertebral
column
Sacrum
Cranium
Facial bones
Clavicle
Scapula
Sternum
Rib
Humerus
Vertebra
Radius
Ulna
Carpals
Phalanges
Metacarpals
Femur
Patella
Tibia
Fibula
(a) Anterior
view
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Tarsals
Metatarsals (b) Posterior
view
Phalanges
Bones of
pectoral
girdle
Upper
limb
Bones of
pelvic girdle
Lower
limb
Skull
Body’s most complex bony structure
Formed by the cranium and facial bones
Cranium – protects brain; site of attachment for head
and neck muscles
Facial bones
– Framework for the face, sense organs, and teeth
– Provide openings for passage of air and food
– Anchor facial muscles of expression
Figure 7.2a The skull: Cranial and facial divisions and fossae.
Bones of cranium (cranial vault)
Coronal
suture
Squamous
suture
Lambdoid
suture
Facial
bones
(a) Cranial and facial divisions of the skull
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Anatomy of the Cranium
Eight cranial bones – two parietal, two
temporal, frontal, occipital, sphenoid, and
ethmoid
Cranial bones thin and strong for their weight
Figure 7.2b The skull: Cranial and facial divisons and fossae.
Anterior cranial
fossa
Middle cranial
fossa
Posterior cranial
fossa
(b) Superior view of the cranial fossae
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Figure 7.2c The skull: Cranial and facial divisions and fossae.
Temporal lobe
of cerebrum
Cerebellum
Frontal lobe
of cerebrum
Posterior
Cranial Middle
fossae Anterior
(c) Lateral view of cranial fossae showing the
contained brain regions
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Figure 7.3 Major cavities of the skull, frontal section.
Cranial cavity
Frontal
sinus
Orbit
Orbit
Ethmoid
sinuses
Maxillary
sinus
Nasal
cavity
Oral
cavity
Frontal
bone
Zygomatic
bone
Ethmoid
bone
Inferior
nasal
concha
Maxilla
Vomer
Mandible
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Frontal Bone
Anterior portion of the cranium
Articulates posteriorly with the parietal
bones via the coronal suture
Major markings include: supraorbital
margins, anterior cranial fossa, frontal
sinuses (internal and lateral to the
glabella)
Frontal Bone
Figure 7.2a
Parietal Bones and associated sutures
Form most of the superior and lateral aspects of the skull
Coronal, sagittal, lambdoid, squamous sutures
Figure 7.3a
Occipital Bone
Sagittal suture
Parietal
bone
Sutural
(Wormian)
bone
Lambdoid
suture
Occipital
bone
Mastoid
process
Forms most of skull’s
posterior wall and base
Occipital
condyle
Cranial cavity floor
Anterior cranial fossa
Middle cranial
fossa
Jugular foramen
Posterior
cranial fossa
Occipital bone
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Foramen magnum
(spinal cord)
View
Temporal Bones
Form the inferolateral aspects of the skull and parts of
the cranial floor
Divided into four major regions – squamous,
tympanic, mastoid, and petrous
Major markings include: zygomatic, styloid, and
mastoid processes, middle cranial fossa
Major openings include: external auditory meatus,
internal auditory meatus, stylomastoid and jugular
foramina, carotid canal
Figure 7.8
Right temporal bone, lateral view
External
acoustic
meatus
Squamous
region
Mastoid
region
Zygomatic process
Mastoid
process
Styloid process
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Tympanic region
Sphenoid Bone
Butterfly-shaped bone that spans the width of the
middle cranial fossa
Forms the central wedge that articulates with all other
cranial bones
Central body, greater wings, lesser wings, and
pterygoid processes
Major markings: sella turcica, hypophyseal fossa,
pterygoid processes, sphenoid sinuses, middle
cranial fossa
Major openings include: optic canals, superior orbital
fissure
Figure 7.7a
Cranial cavity floor
Frontal bone
Optic canal (cn 2)
Sphenoid Lesser wing
Greater wing
Hypophyseal fossa
of sella turcica
Middle cranial
fossa
View
Superior view of cranial interior
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Figure 7.9
Sphenoid bone
Optic canal (cn2)
(cn 3, 4,
part5, 6)
Greater
wing
Hypophyseal
fossa of
sella turcica
Superior view
Lesser wing
Superior
orbital
fissure
Body of sphenoid
Body of sphenoid
Greater
wing
Lesser
wing
Superior
orbital
fissure
(cn 3,4,
part5, 6)
Posterior view
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Pterygoid
process
Ethmoid Bone
Deepest skull bone; lies between the sphenoid and
nasal bones
Forms most of the bony area between the nasal cavity
and the orbits
Major markings include: cribriform plate, crista galli,
perpendicular plate, superior & middle nasal
conchae, ethmoid sinuses
Figure 7.10
Ethmoid bone
Olfactory
foramina
Orbital
plate
Crista galli
Cribriform
plate
Left lateral mass
Ethmoidal
air cells
Perpendicular
plate
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Middle nasal concha
Figure 7.7a
Ethmoid
bone
Cribriform plate
Crista galli
Cranial cavity floor
Frontal bone
Olfactory foramina
Anterior cranial fossa
View
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Facial Bones
Fourteen bones
Only mandible and vomer are unpaired
Paired bones: maxillae, zygomatics, nasals,
lacrimals, palatines, inferior conchae
Mandible
Lower jawbone; largest, strongest bone of face
Major markings include: coronoid process, mandibular condyle,
alveolar margin, mandibular angle, mandibular and mental
foramina
Maxillary Bones
Medially fused bones make up upper jaw and central portion of
the facial skeleton
Facial keystone bones that articulate with all other facial bones
except mandible
Major markings include: palatine, frontal, and zygomatic
processes (artic. w/ respective bones), alveolar margins,
maxillary sinuses
Figure 7.11
Mandible and maxilla
Temporomandibular
joint
Mandible
right lateral view
Mandibular
condyle
Coronoid
process
Mandibular foramen
Alveolar margin
Ramus of
mandible
Mandibular angle
Orbital
surface
Mental foramen
Body of mandible
Articulates with
frontal bone
Zygomatic
process
(cut)
Alveolar
margin
Maxilla, right lateral view
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Facial Bones
Zygomatic Bones - irregularly shaped bones (cheekbones), form
prominences of cheeks and inferolateral margins of orbits
Nasal bones – thin medially fused bones, form bridge of nose
Lacrimal bones – contribute to medial walls of orbits; contain
lacrimal fossae which house lacrimal sacs
Palatine bones – two bone plates, form portions of hard palate,
posterolateral walls of nasal cavity, and small parts of orbits
Vomer – plow-shaped bone, forms part of nasal septum
Inferior nasal conchae – paired, curved bones in nasal cavity,
form part of lateral walls of nasal cavity
Figure 7.4a
Anterior aspect of skull
Frontal bone
Parietal bone
Nasal bone
Sphenoid bone
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxilla
Mandible
Mental
foramen
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Supraorbital margin
Superior orbital
fissure
Optic canal
Inferior orbital
fissure
Ethmoid
bone
Inferior nasal concha
Vomer
Figure 7.5a
Lateral aspect of skull, external view
Frontal bone
Sphenoid bone
(greater wing)
Ethmoid bone
Coronal suture
Parietal bone
Temporal bone
Lacrimal bone
Lambdoid
suture
Squamous
suture
Occipital
bone
Zygomatic
process
Nasal bone
Zygomatic
bone
Maxilla
External acoustic
meatus
Mastoid process
Styloid process
Alveolar
margins
Mandible
Mental foramen
Mandibular condyle
Mandibular ramus
Mandibular angle
(a) External anatomy of the right side of the skull
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Coronoid process
Figure 7.5b
Lateral aspect of skull, internal view
Parietal bone
Coronal suture
Frontal bone
Sphenoid
bone
Squamous
suture
Temporal
bone
Frontal sinus
Crista galli
Nasal bone
Sphenoid sinus
Ethmoid bone
(perpendicular
plate)
Vomer
Lambdoid
suture
Occipital
bone
Maxilla
Alveolar
margins
Sella turcica
of sphenoid
bone
Pterygoid
process of
sphenoid bone
Mandibular
foramen
Palatine bone
Mandible
Midsagittal section showing the internal anatomy of left half of skull
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Figure 7.6a
Inferior aspect of skull, mandible removed
Maxilla
Hard
palate Palatine bone
Zygomatic bone
Temporal bone
(zygomatic process)
Maxilla
Sphenoid bone
(greater wing)
Vomer
Styloid process
External acoustic meatus
Mastoid process
Temporal bone
(petrous part)
Occipital condyle
Parietal bone
Foramen magnum
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Orbits
Bony cavities in which the eyes are firmly encased
and cushioned by fatty tissue
Formed by parts of seven bones – frontal, sphenoid,
zygomatic, maxilla, palatine, lacrimal, and ethmoid
Orbits
(cn 3,4,part5,6)
(cn 2)
frontal
maxilla
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Nasal Cavity
Constructed of bone and hyaline cartilage
Roof – formed by cribiform plate of ethmoid
Lateral walls – formed by superior and middle
conchae of ethmoid, perpendicular plate of
palatine, and inferior nasal conchae
Floor – formed by palatine process of the maxillae
and by palatine
Frontal sinus
Superior, middle, and
inferior meatus
Superior
nasal concha Ethmoid
Middle
bone
nasal concha
Inferior nasal
concha
Nasal bone
Sphenoid
Sphenoid sinus
Pterygoid
bone
process
Palatine bone
Maxillary bone
(palatine process)
Palatine bone
Nasal cavity: left lateral wall
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Nasal septum removed.
Ethmoid
bone
Crista galli
Cribriform
plate
Sella turcica
Frontal
sinus
Nasal bone
Perpendicular
plate of
ethmoid bone
Sphenoid
sinus
Septal cartilage
Palatine
bone
Hard Palatine process
palate of maxilla
Vomer
Alveolar margin
of maxilla
Nasal cavity: Midline structures.
Septum in place; note contributions of ethmoid bone, vomer, septal cartilage
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Paranasal Sinuses
Mucosa-lined, air-filled sacs found in five skull bones:
frontal, sphenoid, ethmoid, and paired maxillary
bones
Named for bones in which they reside
Air enters paranasal sinuses from nasal cavity
Mucus drains into nasal cavity from paranasal sinuses
Lighten skull; enhance resonance of the voice
Figure 7.15 Paranasal sinuses.
Frontal
sinus
Ethmoidal
air cells
(sinus)
Sphenoid
sinus
Maxillary
sinus
(a) Anterior aspect
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(b) Medial aspect
Frontal
sinus
Ethmoidal
air cells
Sphenoid
sinus
Maxillary
sinus
Hyoid Bone
Not actually part of the skull
Lies just inferior to mandible in anterior neck
Only bone that does not articulate with another bone
Attachment point for neck muscles that raise and lower
larynx during swallowing and speech
Anterior aspects of skull
Frontal bone
Parietal bone
Nasal bone
Sphenoid bone
Temporal bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxilla
Mandible
Mental
foramen
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Supraorbital margin
Superior orbital
fissure
Optic canal
Inferior orbital
fissure
Ethmoid
bone
Inferior nasal concha
Vomer
Right side of skull
Frontal bone
Sphenoid bone
(greater wing)
Ethmoid bone
Coronal suture
Parietal bone
Temporal bone
Lacrimal bone
Lacrimal fossa
Lambdoid
suture
Squamous
suture
Occipital
bone
Zygomatic
process
Nasal bone
Zygomatic
bone
Maxilla
Alveolar
margins
Mandible
Mental foramen
Mandibular ramus
Mandibular angle
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Coronoid process
Internal anatomy of left half of skull (midsagittal section)
Parietal bone
Frontal bone
Sphenoid bone
Frontal sinus
Temporal
bone
Crista galli
Nasal bone
Sphenoid sinus
Ethmoid bone
Lambdoid
suture
Occipital
bone
Vomer
Maxilla
Alveolar
margins
Sella turcica
of sphenoid
bone
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Mandibular
foramen
Palatine bone
Mandible
Maxilla
Figure 7.7a
Ethmoid
bone
Cribriform plate
Crista galli
Cranial cavity floor
Frontal bone
Olfactory foramina
Anterior cranial fossa
Optic canal
Sphenoid Lesser wing
Greater wing
Hypophyseal fossa
of sella turcica
Middle cranial
fossa
Temporal bone
Hypoglossal canal
Posterior
cranial fossa
Parietal bone
Occipital bone
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Foramen magnum
View
Inferior view of skull (mandible removed)
Maxilla
Hard
palate Palatine bone
Zygomatic bone
Temporal bone
(zygomatic process)
Maxilla
Sphenoid bone
(greater wing)
Vomer
Carotid canal
Temporal bone
Occipital condyle
Parietal bone
Foramen magnum
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