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Left maxilla
Superior view, anterior at top
Left maxilla
Medial view, anterior to right
Left maxilla
Lateral view, anterior to left
Left maxilla
Inferior view, anterior at top
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arched body with a tooth-bearing alveolar process. Posteriorly each side of the arched body joins the vertically directed rami at the mandibular angle. The superior aspects of the two rami articulate with the
temporal bones at the base of the cranium. The mandible is a strong bone composed predominantly of
compact bone. It houses the lower tooth row in its alveolar arch. The strong masticatory muscles act on
this bone to move it in the temporomandibular joint. Its shape can vary exceedingly with age. If the teeth
are lost, bone gets resorbed on the alveolar surface leading to the thinning of the dental arch. The mandible articulates with two bones.
The mandible, the largest of
the facial bones, forms the
lower jaw. The bone has an
Cranial Bones – Mandible
1 Body of mandible
2 Mental protuberance
3 Mental foramen
4 Mental tubercle
5 Oblique line
6 Digastric fossa
7 Mental spines
8 Mylohyoid line
9 Submandibular fossa
10 Alveolar part
11 Retromolar triangle
12 Ramus of mandible
13 Angle of mandible
14 Mandibular foramen
15 Coronoid process
16 Mandibular notch
17 Condylar process
18 Head of mandible
19 Pterygoid fovea
20 Masseteric tuberosity
21 Pterygoid tuberosity
Mandible
Anterior view
Mandible
Posterior view
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Mandible
Superior view, anterior at bottom
Mandible
Lateral view, anterior to right
Mandible
Inferior view, anterior at bottom
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sieve-like bone because of the many small foramina that transmit the olfactory nerves to the nasal cavity.
This unpaired bone is both complex and delicate and is the central bone of the nasal cavity. Wedged between the two orbits, the bone consists of a median vertical plate, a horizontal plate perforated by many
small foramina, and bilateral pneumatic, labyrinthine regions. The labyrinthine regions form most of the
medial walls of the orbit and the superior and middle nasal conchae. This bone consists of thin laminae of
compact bone surrounding many small air sinuses, which communicate with the nasal cavity. The ethmoid
bone articulates with thirteen bones, more articulations than any other cranial bone.
Cranial Bones – Ethmoid
1 Cribriform plate
2 Cribriform foramina
3 Crista galli
4 Perpendicular plate
5 Ethmoidal air cells
6 Orbital plate
7 Superior nasal concha
8 Middle nasal concha
9 Ethmoidal bulla
10 Uncinate process
11 Ethmoidal infundibulum
Ethmoid bone
Anterior view
Ethmoid bone
Posterior view
Ethmoid bone
Lateral view, anterior at right
Ethmoid bone
Superior view, anterior at top
Ethmoid bone
Inferior view, anterior at top
The term ethmoid comes from the
Greek term ethmos meaning
sieve. Galen called the bone the
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the Greek word zygon meaning yoke, after its resemblance to a yoke placed on oxen. This yoke-shaped
bone has three distinct surfaces, fi ve borders, and two processes. It is situated anterolateral on the face
as the “cheekbone”, and contributes to the lateral and inferior walls of the orbit. It consists of external and
internal laminae of compact bone with an inner core of spongy bone. The zygomatic bone articulates with
four bones.
Cranial Bones – Zygomatic
1 Orbital surface
2 Temporal surface
3 Lateral surface
4 Temporal process
5 Frontal process
6 Zygomatico-orbital foramen
7 Zygomaticofacial foramen
8 Zygomaticotemporal foramen
Right zygomatic bone
Superior view, anterior to top Right zygomatic bone
Inferior view, anterior to top
Right zygomatic bone
Anterior view Right zygomatic bone
Posterior view
Right zygomatic bone
Lateral view, anterior to right
Right zygomatic bone
Medial view, anterior to left
The zygomatic bone, originally named by Galen the
os zygoma, comes from
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in the posterior facial region where it contributes to the roof of the mouth, fl oor of the orbit, fl oor and
lateral walls of the nasal cavity, and to the pterygopalatine fossa. It has a strong horizontal plate with a
delicate vertical lamina that projects superiorly. The palatine bone articulates with six bones.
The palatine bone is a delicate
and intricate bone that forms the
shape of the letter L. It sits deep
Cranial Bones – Palatine
1 Perpendicular plate
2 Sphenopalatine notch
3 Greater palatine groove
4 Pyramidal process
5 Orbital process
6 Lesser palatine foramina
7 Posterior nasal spine
8 Conchal crest
9 Horizontal plate
Left palatine bone
Anterior view, lateral at right Left palatine bone
Posterior view, lateral at left
Left palatine bone
Superior view, anterior at top Left palatine bone
Inferior view, anterior at bottom
Left palatine bone
Lateral view, anterior at left
Left palatine bone
Medial view, anterior at right
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with transverse posterosuperior projections resembling the handles of the plow. This is a small, thin,
unpaired bone that sits in the median plane. It is wider at its superoposterior base and it tapers toward its
antero-inferior apex. It forms the inferior portion of the bony nasal septum. Its surfaces face laterally and
form the lower, medial wall of the nasal cavities. The vomer articulates with six bones and one cartilage.
The vomer is a fl at, triangular bone
that resembles a plow. It has a fl at,
median, vertical blade-like process
Cranial Bones – Vomer
1 Ala of vomer
2 Vomerine groove
3 Vomerine crest of choana
4 Cuneiform part
Vomer
Inferior view, anterior at bottom
Vomer
Superior view, anterior at bottom
Vomer
Lateral view, anterior at left
Vomer
Anterior view
Vomer
Posterior view
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upon which a pair of eye glasses rest. The external surface of the bones provides attachment for the
procerus and nasalis muscles, two thin muscles of facial expression. Each nasal bone articulates with
four bones.
The paired nasal bones are small, rectangular bones with a subtle bow-like
shape. They form the bridge of the nose
Cranial Bones – Nasal
1 Ethmoidal groove
2 Nasal foramina
3 Superior border
4 Inferior border
5 Lateral border
6 Medial border
Left nasal bone
Posterior view, lateral at right
Left nasal bone
Anterior view, lateral at left
Left nasal bone
Lateral view, anterior at right
Left nasal bone
Medial view, anterior at left
Left nasal bone
Superior view, anterior at bottom
Left nasal bone
Inferior view, anterior at bottom
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This is a small, delicate bone that projects from the lateral wall of the nasal cavity. It is scroll-like in appearance as it arches inferiorly and laterally from the nasal cavity’s lateral wall. The medial surface of the bone
is convex and furrowed by many longitudinal grooves that transport blood vessels beneath the thick nasal
mucosa that covers this surface. The lateral surface of the bone is concave and forms most of the superior and medial boundary of the inferior nasal meatus. The inferior border of the bone has a rough, spongy
appearance. Superiorly the bone forms an articular border with four bones.
Cranial Bones – Inferior Nasal Concha
1 Lacrimal process
2 Maxillary process
3 Ethmoidal process
4 Lateral surface
5 Medial surface
Left inferior nasal concha
Posterior view, lateral at right
Left inferior nasal concha
Anterior view, lateral at left
Left inferior nasal concha
Lateral view, anterior at right
Left inferior nasal concha
Medial view, anterior at left
Left inferior nasal concha
Superior view, anterior at right
Left inferior nasal concha
Inferior view, anterior at right
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the “tear duct.” This small, delicate, quadrate-shaped bone has a vertical axis that is slightly longer than
its horizontal axis. It is extremely thin. When it is held up to a light source, the light easily penetrates the
bone. The bone sits in the anterior part of the medial wall of the orbit. The orbital surface is smooth and
fl at in its posterior half where it contributes to the medial wall of the orbit. Anteriorly this surface has a
longitudinal groove that ends posteriorly in a longitudinal crest that is hook-shaped inferiorly. This groove
supports the nasolacrimal duct. Covered with mucous membrane, the slightly rough, medial surface of the
bone contributes to the nasal cavity. The lacrimal bone articulates with four bones.
The lacrimal bone derives its name
from the Latin word meaning
tear because the bone houses
Cranial Bones – Lacrimal
1 Posterior lacrimal crest
2 Lacrimal groove
3 Lacrimal hamulus
Left lacrimal bone
Anterior view, lateral at right
Left lacrimal bone
Lateral view, anterior at left
Left lacrimal bone
Posterior view, lateral at left
Left lacrimal bone
Medial view, anterior at right
Left lacrimal bone
Superior view, lateral at right
Left lacrimal bone
Inferior view, lateral at left
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three small bones occupy the middle ear cavity, where they transmit and amplify the sound waves from the tympanic membrane to the inner ear. From lateral to medial the bones are the malleus, the incus, and the stapes, or in layman’s terms the
hammer, the anvil, and the stirrup, because of their striking resemblance to these structures.
The auditory ossicles are
the smallest bones of the
human skeleton. These
Cranial Bones – Auditory Ossicles
1 Malleus
2 Incus
3 Stapes
4 Handle of malleus
5 Head of malleus
6 Neck of malleus
7 Lateral process
8 Anterior process
9 Body of incus
10 Long limb
11 Lenticular process
12 Short limb
13 Head of stapes
14 Anterior limb
15 Posterior limb
16 Footplate
Auditory ossicles in situ within temporal bone
Anterior view, left temporal bone
Left auditory ossicles
Anterior view, lateral at left
Left malleus
Anterior view, lateral at left
Left incus
Lateral view, anterior at left
Left stapes
Superior view, lateral at left
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occupies the ventrosuperior neck just inferior to the mandible. It serves as a skeletal attachment site for
muscles associated with the tongue, larynx, and pharynx. It consists of fi ve elements — a body and bilateral lesser and greater cornua. The body is the rectangular ventral element that sits in the transverse
plane. Projecting posterolaterally from the body are the paired, long, slender greater cornua. At the junction of the greater cornua and the body are smaller superior projections, the lesser cornua.
Suspended from the styloid processes
of the temporal bones by the stylohyoid
ligaments, the U-shaped hyoid bone
Cranial Bones – Hyoid
1 Body
2 Lesser horn
3 Greater horn
Hyoid bone
Anterior view
Hyoid bone
Lateral view, anterior at right
Hyoid bone
Superior view, anterior at bottom
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of the vertebrae has a similar structure. The bones of the vertebral column are grouped into seven cervical vertebrae, twelve thoracic vertebrae, fi ve lumbar vertebrae, the sacrum consisting of fi ve fused segments, and the
coccyx comprised of three to fi ve fused segments, most typically four. The column is the central axis of the body
that supports the limbs and the cranium, protects the spinal cord, and provides attachment for muscles that
move this fl exible column of bones.
The vertebral column consists of 26 bones that develop
from a series of 33 identical embryonic body segments. Because they develop from similar repeating segments, each
Vertebral Column
1 Cervical vertebrae
2 Thoracic vertebrae
3 Lumbar vertebrae
4 Sacrum
5 Coccyx
6 Thoracic kyphosis
7 Sacral kyphosis
8 Cervical lordosis
9 Lumbar lordosis
10 Intervertebral foramen
Vertebral column
Anterior view
Vertebral column
Lateral view, anterior at right
Vertebral column
Posterior view
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