Download facial bones

Anatomy of Skeletal Elements
Bone Surface Markings
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Foramen = opening (arteries, nerves)
Fossa = shallow depression
Sulcus = shallow groove (artery or nerve)
Canal = longer, tubelike opening
Fissure = narrow, cleftlike opening
Notch = indentation at the end of a bone
Meatus = type of canal
Condyle = large, round protuberance, attachment of muscles
Epicondyle = above or upon a condyle
Facet = smooth flat articular surface
Trochanter = very large projection
Tuberosity = large, rounded, roughened projection
Tubercle = rounded eminence/elevation
Crest = roughened border or ridge
Spine = sharply pointed projection
Skeletal system includes
• Axial division
– Skull and associated bones
• Auditory ossicles
• Hyoid bones
– Vertebral column
– Thoracic cage
• Ribs sternum
• Appendicular division
-Pectoral girdle
-Pelvic girdle
The Axial Skeleton
• Axial division
– Skull and associated bones
• Auditory ossicles
• Hyoid bones
– Vertebral column
– Thoracic cage
• Ribs sternum
The Skull and Associated Bones
Sutures
• Immovable joints (synarthrotic, fibrous joints)
• Form boundaries between skull bones
• Five sutures
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Coronal
Sagittal
Lambdoid
Squamous
Frontonasal
The Adult Skull
•skull = 22 bones
•cranium = 8 bones: frontal, occipital, 2 temporals, 2 parietals, sphenoid and
ethmoid
•facial bones = 14 bones: nasals, maxillae, zygomatics, mandible, lacrimals,
palatines, inferior nasal conchae, vomer.
•skull forms a larger cranial cavity
-also forms the nasal cavity, the orbits, paranasal sinuses
mandible and auditory ossicles are the only movable skull bones
•cranial bones also: attach to membranes called meninges
-stabilize positions of the brain, blood vessels
-outer surface provides large areas for muscle attachment that
move the head or provide facial expressions
Figure 6.4 Sectional Anatomy of
the Skull, Part I
• Frontal bone
– Forms the forehead
– Roof of the orbit
– articulates with
parietal, sphenoid,
lacrimal, nasal,
ethmoid, zygomatic
and maxilla
– superior and lateral to
glabellar region –
frontal sinuses
– inferior portion –
supraorbital ridges
with supraorbital
notch (supraorbital
nerve and artery)
•Parietal bones
-Part of the superior and lateral surfaces of the cranium
-articulate with each other – sagittal suture
-articulate with occipital, frontal,
temporal and sphenoid bones
•Temporal bone
-Forms wall of jugular foramen
-Petrous part: posterior portion
-Tympanic part: associated with ear canal
-Squamous part: anterior portion, fan-shaped
-zygomatic process
-forms cranial portion of the TMJ joint
-inferior to zygo. process – mandibular fossa (mandibular condyle)
•Temporal bone – petrous portion
•houses the inner ear
-inferior aspect – mastoid process
(air spaces that communicate with the
middle
ear)
-also for attachment of
sternocleidomastoid muscle
-inferior to mastoid process –
mastoid foramen
-anterior to mastoid process –
external acoustic meatus
-inferior and medial to the MP –
styloid process (muscle attachment)
-stylomastoid foramen (7th
cranial)
• Occipital bone
• Part of the base of the skull
• articulates with parietal, temporal
and sphenoid
• Surrounds the foramen magnum
• lateral to the FM – hypoglossal
canal (12th cranial)
• projections = occipital condyles
• Forms part of the jugular foramen
• Sphenoid bone
– Contributes to floor of
cranium
– articulates with the frontal,
ethmoid, temporal
zygomatic, parietal
maxillary, palatine, vomer
& occipital bones
– Bridges cranial and facial
bones
– Optic canal allows passage
of optic nerve
-Foramina:
-superior orbital fissure – 3rd, 4th, 6th cranials
-foramen ovale – 5th cranial (mandibular)
-foramen rontundum – 5th cranial
-foramen spinosum – middle meningeal artery
-optic canal
-greater wing – posterolateral portion
-lesser wing
-Pterygoid processes – inferior to the
greater wings – sites of muscle
attachment
-lateral and medial plates with a
fossa located between
-body: sella turcica, tuberculum
sellae, dorsum sellae, sphenoid
Ethmoid bone
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Irregularly shaped bone
Forms part of orbital wall
Forms roof of nasal cavity
articulates with: frontal, sphenoid,
lacrimal and maxillary bones
– connects with the vomer
– two lateral masses – contain the
ethmoid sinuses
• projections called the superior and
middle nasal conchae
– two plates: perpendicular plate
& the cribiform plate
– Cribiform plate: perforations for
olfactory nerve, midline is the crista
galli
– Perpendicular plate = upper part
of nasal septum
14 Facial Bones
Nasal (2)
Mandible (1)
Inferior nasal conchae (2)
Maxillae (2)
Lacrimal (2)
Zygomatic (2)
Palatine (2)
Vomer (1)
Bones of the Face
• Maxillae
– Paired bone
– Largest of facial
bones
– Form upper jaw
– body = orbital, nasal,
infratemporal and
facial surfaces
– body contains the
maxillary sinuses
Maxillary bones: Anterior View
• frontal process – articulates with frontal bone and nasal bones & forms medial
orbital rim
• facial surface – body of maxilla
– infraorbital foramen – landmark for local
– inferior to this IF – canine fossa
– inferior portion of the maxilla – alveolar processes of the teeth (contains the roots of
the maxillary teeth
• Inferior view:
• zygomatic process:
articulates with
zygomatic bone
– palatine process – major portion of
the hard palate
– joined by the median palatine
suture covered by the median
palatine raphe (fibrous tissue)
– anterior portion – incisive foramen
(nasopalatine nerves and vessels)
Zygomatic Bones
• Cheekbones
• Lateral wall of orbit along with sphenoid
• Part of zygomatic arch along with part of temporal
• Palatine bones
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Small, L-shaped
link between maxilla and sphenoid
Form posterior portion of hard palate
Contribute to floor of orbit
made up of horizontal plate and a vertical plate +
orbital process
-midpoint of horizontal plate = nasal crest
-vertical plates – forms lateral wall of
nasal cavity
-two foramina in each palatine bone
1. greater palatine – about 3rd molar
-greater palatine nerve, landmark
for administration of local
2. lesser palatine – lesser palatine
nerve to soft palate
• Inferior nasal concha
– Located on each side of nasal septum
– Increase epithelial surface
– Create turbulence in inspired air
• Lacrimal bones
– Smallest bones in skull
– Forms nasolacrimal groove leading to nasolacrimal canal
– Delivers tears to nasal cavity
Palatine & Vomer
• Vomer
– posterior part of nasal septum
– Forms inferior portion of nasal septum
– Articulates with maxillae and palatines
Mandible
• lower jaw
• only freely movable bone of the skull
• moving articulations with temporal bone
Mandible: Anterior surface
• many landmarks on the
body
– mental protruberence –
beneath the roots of the
mandibular incisors
– faint ridge at the midline –
mandibular symphysis
(fusion of right and left
processes during
development)
– lateral to the midline –
mental foramina (mental
nerve and vessels into the
mandibular canal)
Mandible: Anterior &
Lateral surfaces
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superior to the body – alveolar
processes of the mandible
body is capable of elongation in
children
like the maxillary alveolar processes,
the alveolar processes of the mandible
can become completely resorbed upon
loss of teeth
ramus – superior and posterior to the
body
– primary area for attachment of muscles
for mastication
– also grows
– anterior border is the coronoid process
– posterior border – mandibular condyle
– between in the mandibular notch or
coronoid notch (landmark for local)
– ramus and body joined at the external
oblique line
– superior to this – coronoid notch
Mandible: Inferior
surface
-visible are the genial tubercles – or mental spines
-muscle attachment area
-two fossas: 1) sublingual (sublingual salivary gl.)
2) submandibular (submandibular gl.)
-divided by the mylohyoid line (mylohyoid m.)
-mandibular foramen – opening of the mandibular canal
-for the exit of the alveolar nerve and vessels
-can be lost with alveolar process reabsorption
-overhanging the foramen – lingula (attachment of sphenomandibular
ligament – TMJ)
The Hyoid Bone
• Suspended by stylohyoid ligaments
• Consists of a body, greater horns and lesser
horns
• Base for muscles of the tongue and larynx
The Orbital and Nasal Complexes
• Orbital complex
– Bony recess that holds the eye
– Seven bones
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Frontal bone
Lacrimal bones
Palatine bones
Zygomatic bones
Ethmoid
Sphenoid
Maxillae
Orbital Complex: Eye socket
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medial wall: frontal process, lacrimal bone and part of
ethmoid
• lateral wall: sphenoid, zygomatic
• floor: maxillary, zygomatic
• back: sphenoid + superior orbital
fissure
-top: frontal bone
• sphenoid and frontal bones
are separated by the infaorbital
fissure (infraorbital & zygomatic
nerves, infraorbital artery
and inferior opthalmic vein)
-continues on as the infraorbital sulcus
-becomes the infraorbital canal
-terminates on the facial surface as the
infraorbital foramen (infraorbital nerve)
• Bones and
cartilage that
enclose the nasal
cavity
The Nasal Complex
Nasal bones & cavities
• Nasal bones
– Paired bones – forms the bridge
– Articulate with frontal bone
– nasion: junction between frontal and nasal bones
• Nasal cavity
– anterior, triangular opening: piriform aperture
-lateral wall: nasal conchae (superior, middle, inferior)
-superior and middle - ethmoid
-inferior nasal conchae – separate bone
-divided into separate cavities – nasal septum
-anterior portion is nasal septal cartilage
-superior portion formed by perpendicular plate
-inferior portion formed by the vomer
deviated nasal septum: nasal septum divides the nasal cavity into right and left
halves
-three components: vomer, septal cartilage & perpendicular plate of the
ethmoid
-deviation results in a later deflection of the septum
-severe deviation may affect breathing
Paranasal Sinuses
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• part of the nasal complex
• Paired cavities in ethmoid,
sphenoid, frontal and maxillary
• Lined with mucous membranes
and open into nasal cavity
though openings called ostia
• Resonating chambers for voice,
lighten the skull
• Sinusitis is inflammation of the
membrane (allergy)
frontal sinuses: frontal bone, separated by a septum • infection can easily spread from
one sinus to the other through
– connects with nasal cavity – frontonasal duct
the nasal cavity
sphenoid sinuses: body of the sphenoid bone
– also drain into nasal cavity
• can also spread to other tissues
ethmoid sinuses: or ethmoid air cells, located in the
lateral masses
– anterior, middle and posterior sinuses
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maxillary: body of the maxilla
– size varies with individual and age
– largest of the sinuses
– close proximity to alveolar processes – periodontal
tissues may be in direct contact with sinus’ mucus
membranes
– secondary sinusitis
Cranial Fossae
• Depressions in cranial
floor
• Anterior cranial fossa
– Frontal bone, ethmoid,
lesser wings of
sphenoid
• Middle cranial fossa
– Sphenoid, temporal
bones, parietal bones
• Posterior cranial fossa
– Occipital bone,
temporal bones,
parietal bones
Cranial Fossae
The Vertebral Column
http://www.wisc-online.com/objects/index.asp?objID=AP12104
Adult Vertebral Column
• 26 vertebrae
– 24 individual vertebrae
– Sacrum
– Coccyx
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Seven cervical vertebrae
Twelve thoracic vertebrae
Five lumbar vertebrae
Sacrum and coccyx are fused
Typical Vertebrae
• Body
– weight bearing
• Vertebral arch
– pedicles
– laminae
• Vertebral foramen
• Seven processes
– 2 transverse
– 1 spinous
– 4 articular
• Vertebral notches
Typical Cervical Vertebrae (C3-C7)
• Smaller bodies
• Larger spinal canal
• Transverse processes
– shorter
– transverse foramen
for vertebral artery
• Spinous processes of
C2 to C6 often bifid
• 1st and 2nd cervical
vertebrae are unique
– atlas & axis
Atlas & Axis (C1-C2)
• Atlas -- ring of bone, superior facets for occipital condyles
– nodding movement at atlanto-occipital joint signifies “yes”
• Axis -- dens or odontoid process is body of atlas
– pivotal movement at atlanto-axial joint signifies “no”
Thoracic Vertebrae
(T1-T12)
• Larger and stronger bodies
• Longer transverse &
spinous processes
• Facets or demifacets on
body for head of rib
• Facets on transverse
processes (T1-T10) for
tubercle of rib
Lumbar Vertebrae
• Strongest & largest
• Short thick spinous &
transverse processes
– back musculature
Intervertebral Foramen & Spinal Canal
• Spinal canal is all vertebral foramen together
• Intervertebral foramen are 2 vertebral notches together
Herniated discs:
•distortion in the
intervertebral discs
between vertebral bodies
•bulges out into the
intervertebral foramen
•presses on spinal nerves
which pass through this
foramen
•pain, numbness, paralysis