Osteology of max n mand/prosthodontic courses

DR.SAPNA.B
POST GRADUATE STUDENT
PREVENTIVE & COMMUNITY
DEPARTMENT
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

INTRODUCTION
BASIC SCIENCE ABOUT BONE
• Development of bone
• Structure of bone
• Classification of bone
• Bone physiology
• Bone composition
• Bone histology.

OSTEOLOGY OF MAXILLA
Development
Structure
Age changes
Normal Radiographic features
OSTEOLOGY OF MANDIBLE
Development
Structure
Age changes
Normal Radiographic feature
DEFECTS IN MAXILLA AND MANDIBLEwww.indiandentalacademy.com

Y: is the scientific study of bone.
rived from Latin word Os and from
osteon meaning bone.
the body articulated together
he skeleton which provides
o body.


(www.wikipedia.com)
Osteology: is a detailed study of the ----
 Structure of bones,
 Skeletal elements,
 Teeth,
 Morphology,
 Function,
 Disease,
 Pathology
The process of ossification (from cartilaginous
molds),
The resistance and hardness of bones (biophysics),

Often used by scientists with identification of
human remains with regard to age, death,
gender, growth, and development in a bicultural
context.

knowledge of osteology is necessary for-
 For getting a clear concept of gross anatomy
because the bones are the key structure of any
part the body.
 To understand the disease processes in bones
and for planning measures for healing and
restoration of their functions.

Osteological approaches are frequently applied
to investigations such as
- Forensic science,
- Physical anthropology,
- Archaeology.

Has a place in research on topics including:
- Health and Disease ,
- Genetics of early populations ,
- war crimes investigations ,
- Identification of Unknown remains,
- population migration,
- Criminal investigations.
(R.N. BAJPAI-HUMAN OSTEOLOGY, 1ST
EDITION, 1986)www.indiandentalacademy.com

BONE
Bone is a living, hardest structure of the human
body forms the skeletal framework. It is a
specialized mineralized connective tissue
COLLAGEN is a protein that provides a soft
framework, and
CALCIUM PHOSPHATE is a mineral that adds
strength and hardens the framework.www.indiandentalacademy.com

This combination of collagen and calcium
makes bone strong and flexible enough to
withstand stress.
More than 99 percent of the body’s calcium is
contained in the bones and teeth.
The remaining 1 percent is found in the blood.www.indiandentalacademy.com

DEVELOPMENT OF BONE

The skeleton arises from fibrous
membranes
and hyaline cartilage during the first month
of embryonic development.
These tissues are replaced with bone by two
different bone-building, or ossification
processes during the development called
osteogenesis.

OSTEOGENESIS
The process of bone formation is called
osteogenesis.
Bone formation take place in two ways:
From cartilaginous tissues :
i.e. Endochondral bone formation.
From the membranous connective tissue :
i.e. Intramembranous bone formation.

ENDOCHONDRAL BONE FORMATION

Mesenchymal cells differentiates into chondroblasts,
produce cartilage matrix model of hyaline cartilage
Increase in length (interstitial growth) &
thickness(appositional growth)
chondrocytes in the mid region, accumulate glycogen for
energy & produce enzymes to catalyze chemical
reaction, which trigger calcification

once cartilage gets calcified
nutrients required for cartilage cells no longer diffuse
leading to death of cartilage cells
lacunae of the cells killed are empty
a nutrient artery penetrates the perichondrium & along with it
the mesenchymal cells accompany which differentiates into
osteoblasts & begin to deposit osteoid
near the middle of the model capillaries of the periosteum
grow into distintegrating calified cartilage the vessels
associated with osteoblasts, osteoclasts & red marrow cells are
known as periosteal bud (primary ossification center).

Secondary ossification center develops around the
time of birth, when the epiphyseal arteries enter the
epiphyses.
different from primary ossification center,
- spongy bone retained in interior of the ephiphyses
- no medullary cavities are formed
- hyaline cartilage remains covering the epiphyses
as articular cartilage & between epiphyses &
diaphysis as epiphyseal platewww.indiandentalacademy.com

INTRAMEMBRANOUS BONE FORMATION
Here, the undifferentiated mesenchymal cells
of the membranous connective tissue
changes to osteoblasts and elaborate osteoid
matrix. The matrix calcifies and bone results.

Endochondral bone formation

mesenchymal cells become vascularized, cluster
& differentiates into osteoprogenitor cell
then into osteoblasts
( center of ossification )
osteoblasts secrete the organic matrix of bone
stop secretion once completely surrounded by the matrix,
cells now are called the osteocytes
later calcium & mineral salts are deposited
on outside of bone, vascularized mesenchyme
develops into periosteum
Intramembranous ossification:

Intramembranous ossification is the predominant
mode of growth in the skull.
Bone tissues laid down by the periosteum,
endosteum, sutures and the periodontal membrane
are all intramembranous in formation.

ANATOMY: STRUCTURE OF BONE
(FROM WIKIPEDIA, THE FREE ENCYCLOPEDIA)

•Medularly cavity -- The medullary (marrow)
cavity is the space within the
Bone containing either red or yellow bone
marrow. Red bone marrow consists of blood
precursors while yellow marrow consists of
adipose tissue. Red bone marrow is a network of
blood vessels, connective tissue, and blood-
forming cells. Red blood cells are formed in the
red bone marrow. All bones have blood vessels
and nerves.

•Diaphysis -- The diaphysis of a long bone is its shaft or
long main portion.
•Epiphysis -- The epiphysis of a long bone is its end.
The two ends
together are called the epiphyses. Each epiphysis is
covered with articular cartilage.
•Articular cartilage -- Articular cartilage is a thin layer
of hyaline cartilage
Covering the articular surfaces of the epiphysis at a joint.

•Periosteum -- The periosteum is the double-layered
connective tissue, Surrounding the bone except where the
articular cartilage. It is divided into an outer fibrous layer
and an inner osteogenic layer.
Fibrous periosteum -- The outer fibrous layer of
the periosteum is Composed of dense irregular
connective tissue containing blood vessels,
lymphatics, and nerves that pass into the bone.
Osteogenic periosteum -- The inner osteogenic
layer of the Periosteum contains elastic fibers and
various bone cell types, particularly osteoprogenitor
cells that give rise to new osteoblasts when stimulated.

Functions Periostium -- The periosteum
helps in bone growth, Repair and nutrition.
In addition, it provides attachment points for
skeletal muscles.

TYPES OF BONES (CLASSIFICATION OF BONES)
(R.N. BAJPAI-HUMAN OSTEOLOGY, 1ST
EDITION, 1986)
I) ACCORDING TO MORPHOLOGY OR SHAPE:
 Long bones - these are the bones connected with
large movement. They are long and cylindrical bones
Eg,- The femur (thigh bone),
The humerus (upper bone in the arm) and
The phalanges (fingers and toes).

Short bones – These are usually cuboidal,
wedge, boat or round shaped bones , and
associated with smaller, more complex
movements.
Eg, Metacarpals (small bones in the base of the hand)
Metatarsals (in the feet).

Flat bones - these bones protect the internal
organs and this include
- The skull (cranium),
- Ribs,
- Scapula (shoulder blade),
- Sternum (breast bone) and
- The pelvic girdle.

Irregular bones - these bones are irregular
in shape.
Eg, The vertebrae and
Some facial bones.

Sesamoid bones - these are small bones
held within tendons.
Eg, patella (knee cap). Cartilage separates the
femur and the patella, and acts as a shock
absorber.

Pneumatic bones – some cranial bones like
maxilla, ethmoid and frontal bones have large air
spaces in their interior lined with mucous
membrane. This is to make the bones lighter, they
are called pneumatic bones.
Generally in other bones the interior of bone is
spongy and has bone marrow. These features are
absent in pneumatic bones.

II) ACCORDING TO OSSIFICATION:
•Membranous bone-formation of bone from
mesenchyme, esp. flat bones found in the skull
• Cartilaginous bone -formation of bone from
cartilage

III)ACCORDING TO STUCTURAL OSSIFICATION:
 Compact bone - Dense in texture, like ivory, Compact
bone contains very few spaces. The layers of bone matrix are
packed together tightly, forming osteons (Haversian systems).
It forms the external layer of all bones, providing protection
and support and helps the long bone resist the stress of weight
applied to them.

 Cancellous bone-
Spongy bone consists
of lamellae (layers) of
bone matrix arranged in
an irregular latticework
of thin plates of bone
called trabeculae. The
spaces between the
trabeculae are a part of
the medullary cavity of
the bone.

Lamellar bone-
Structure of any mature bone shows layers of
lamellae, is called lamellar bone

Woven bone-
Structure of newly formed bone does not have a lamellar
structure. The collagen fibres are present in bundles that
appear to run randomly interlacing with each other. Because of
the interlacing of fibre bundles this kind of bone is called
woven bone. It is later replaced by lamellar bone.

skull.

PHYSIOLOGY:
FUNCTIONS OF BONE:-
Support -- Bone provides a framework for the
body by supporting soft tissues and providing
points of attachment or most of the skeletal
muscles.
Protection -- Bones protect many internal organs
from injury very well, such as the brain and
spinal cord. In addition, the heart, lungs, and
reproductive organs are given some degree of
protection.www.indiandentalacademy.com

Movement -- Most skeletal muscles attach to
bones. When the muscles contract, they pull on
bones to activate lever systems, and movement is
produced. e.g., Mandibular movement.
Mineral homeostasis -- Bone tissue stores a
number of minerals, Particularly calcium and
phosphorus. Under control of the endocrine
system, bone releases the minerals into the blood
or stores the minerals in bone matrix to maintain
critical mineral balances.

Blood cell production -- In all bones of the infant
and certain bones of the adult, a connective tissue
known as red marrow produces blood cells by the
process of hematopoiesis.
Storage of energy -- In some bones, yellow bone
marrow stores lipids, creating an important energy
reserve for the body.
(from wikipedia, the free encyclopedia)

CHEMICAL COMPOSITION: OF BONE
ORGANIC INORGANIC
( 33% ) (67%)
Collegen fibrills ( The
mineral salts are crystallized
onto the collagen fibers,
giving bone its hardness)
 Ground substance(non
collagn protein)
-- mucopolysacharides protein
complex 1%
-- resistant protein 5%
Bone salts
calcium:
- calcium phosphate
- calcium carbonate
- calcium fluoride
magnesium chloride
Hydroxy appatite crystals
Ca10(po4)6(OH)2

HISTOLOGY OF BONE

 A section of any bone seems to be composed of two
kinds of tissue,
 COMPACT TISSUE (cortical bone)
 CANCELLOUS TISSUE (trabecular bone, spongy
bone)

COMPACT TISSUE:-
Always placed on
the exterior of the
bone. It is more
dense tissue usually
found on the surface
of bones. It is
organized in
cylindrical shaped
elements called
osteons composed of
concentric lamellae

CANCELLOUS TISSUE:-
Is quite porous and it
is organized in
trabecules, these are
slender fibers or
lamellae, which join to
form a reticular
structure, which
resemblance to
lattice-net work

Bone is a modified connective tissue consists
of bone cells like
Osteocytes
Osteoblasts
Osteoclasts
Osteoprogenitor cells

OSTEOCYTES
Constitutes the major cell type
scattered within the bone
matrix & interconnected by
numerous cellular extension to
form a complex cellular
network.

OSTEOBLASTS
Are the cells that form new bone. They have only
one nucleus. Osteoblasts work in teams to build
bone. They produce new bone called "osteoid"
which is made of bone collagen and other
protein. Then they control calcium and mineralwww.indiandentalacademy.com

OSTEOCLASTS
Are large multinucleated giant cells that
dissolve the bone.
OSTEOPROGENITOR CELLS
From which osteoblasts and osteocytes are
derived.

JAWS
• TOOTH BEARING BONES.
• THEY COMPRISE OF THREE BONES.
• TWO BONES FORMS UPPER JAW-MAXILLA
• LOWER JAW IS SINGLE BONE- MANDIBLE.

-Maxilla, is one of the largest of facial bones
(CORTICAL BONE).
It is a paired bone jointly form the
Upper jaw
Buccal roof
Floor
Lateral wall of nasal cavity
Orbital floor
Part of infratemporal
Part of inferior orbitalwww.indiandentalacademy.com

DEVELOPMENT OF MAXILLA

•Maxilla ossify by intra-membranous ossification
• Maxilla develops from a center of ossification in the
Mesenchyme of maxillary process of the first arch in the
six month of intrauterine life.
• No arch cartilage or primary cartilage exists in maxillary
process, but centre of ossification is closely associated with
the cartilage of nasal capsule.

•The center of ossification appears in the angle between the
divsions of a nerve where the anterosuperior dental nerve is
given off from the inferior orbital nerve.
•From this center bone formation spreads ….
-Posteriorly below the orbit toward the developing zygoma
- Anteriorly toward the future incisor region.
- Superiorly to form the frontal process.

.
• During this pattern of bone deposition it forms a bony
trough for infraorbital nerve called infra orbital foramen.
• From this downward extension of bone forms the lateral
alveolar plate for the maxillary tooth germs. also spreads into
the palatine process to form hard palate.
• The medial alveolar plate develops at junction of the palatal
process and the main body of the forming maxilla.
•This plate, together with lateral counterpart, forms a trough of
bone around maxillary tooth germs, which enclosed in bony
crypts

•Secondary cartilage also contributes to the development of
maxilla
i.e., zygomatic cartilage from the developing zygomatic
process
• At birth the frontal process of the maxilla is well marked
•But the body of the bone consists of little of alveolar process
containing the tooth
• Distinguishable zygomatic and palatal process.

•The body of the maxilla is relatively small because the
maxillary sinus has not developed. It forms during the
sixteenth week as a shallow nasal aspect of the developing
maxilla. At birth the sinus is still a rudimentary structure
about the size of peanut.

Postnatal development of the maxilla:
The growth of the maxilla should adapt to the
basicranium to which it is attached and also to the
mandible with which it functions (in mastication,
speech, facial expression, respiration etc).
The mechanism for growth of the maxilla is the
sutures, nasal septum, the periosteal, endosteal
surfaces, and the alveolar process. Mills pointed out
that the maxilla increases in size by subperiosteal
activity during postnatal growth even though the
periosteum has different names at different sites.

Over the majority of areas it is called simply,
periosteum and over some areas, it is called
mucoperiosteum. Where the periosteum of one bone
meets that of another bone, it is called a suture.
Periosteum is also called periodontal membrane where the
alveolar bone meets the modified bone of tooth’s root
(cementum). Periosteum though called differently at
different sites carry out the role of remodeling. The maxilla
is attached to the cranial vault and the cranial base by the
following sutures.
a) Zygomatico-maxillary suture
b) Fronto-maxillary suture
c) Zygomatico-temporal suture
d) Pterygo platine suture.

This suture system is the most complicated found in
the human body.Endochondral mechanism for bone growth
is not very prevalent in the mid face. Only growth by
endochondral mechanism is the midfacial extensions of the
ethmoid.
The growth of the cartilaginous part of the nasal
septum has long been regarded as a source of the force that
displaces the maxilla downward and forward (antero-
inferiorly). This theory does not hold good in its entirety at
present. Most of the bone formation occurs at the mid face
by intra membranous process. All the endosteal and
periosteal surfaces are blanketed by localized growth fields,
which operate essentially independently but in harmony with
each other. Thus, surface growth remodeling is very active
providing much regional increase and remodeling which
accompany and adapt to the additions taking place inwww.indiandentalacademy.com

Maxilla is joined to the cranial base and the
position of the maxilla is dependent on the growth
at the sphenooccipital and spheno-ethmoidal
synchondrosis.
Maxillary postnatal growth can be divided
into –
1. Shift in position of maxillary complex-
secondary displacement or translocation or
passive displacement.
2. Enlargement of the complex itself – Primary
displacement or transposition or active

Most of the bone of the cranial base is formed
by the cartilaginous process. Later the cartilage is
replaced by bone but certain bands of cartilage
remain at junction of various bone. These areas
are called synchondrosis. These are important
growth sites. These are the synchondrosis
between the sphenoid and occipital bones, or
spheno-occipital synchondrosis, the intersphenoid
synchondrosis, between two parts of the sphenoid
bone and the spheno-ethmoidal synchondrosis
between the sphenoid and ethmoid bones.

Bone gets deposited on the posterior facing
cortical plate surface of maxillary tuberosity. The
endosteal surface within the tuberosity is having a
resorptive field. The amount of anterior maxillary
shift is equal to the amount of bone deposited on
the posterior surface of the tuberosity.
The bone resorption on nasal (superior) side
of the palate and bone deposition on the inferior
oral side produces a downward growth of the whole
palate. In maxilla, the palate grows downward by
periosteal resorption on the nasal side and
periosteal deposition on the oral side.

The maxillary height increases because of
sutural growth towards the frontal and zygomatic
bone and oppositional growth in the alveolar
process. Apposition also occurs on the floor of
the orbits with resorptive remodeling of the lower
surfaces. The nasal floor is lowered by resorption
while apposition occurs on the hard palate. The
growth at the median suture produces more
millimeters of width increase than appositional
remodeling but surface remodeling must
everywhere accompany sutural additions.

Alveolar remodeling contributing to
significant early vertical growth is also important
in the attainment of width because of
divergence of alveolar processes. As they grow
vertically, their divergence increases the width.
Upto the time that the mandibular condyles
have deceased their most active growth,
maxillary alveolar process increase constitutes
nearly 40% of the total maxillary height
increases.

STRCUTRE OF MAXILLA
BODY>>>>>>4 SURFACES
ANTERIOR
INFRATEMPORAL
ORBITAL
NASAL
• PROCESS>>>4 PROCESSES
ZYGOMATIC,FRONTAL
ALVEOLAR,PALATINE

Each maxilla consists of a body and its processes,
like zygomatic, frontal, alveolar and palatine
processes.

Attachments and relations
1. incisive fossa- depressor
septi
2. Canine fossa-levator anguli
oris
3. Infra orbital margin-levator
labi superioris
4. Tuberosity-fibres of medial
pterygoid
5. Lateral lacrimal groove-
inferior oblique muscle
6. Anterior lacrimal crest-
medial palpebral ligament

7. Frontal process-
orbicularis oculi,levator
labi superioris aleque
nasi,
8. Zygomatic process-
origin to masseter
9. Alveolar process-
buccinator.

Associated nerves and vesselsAssociated nerves and vessels
1. Infra orbital foramen-infra orbital nerve and vessels
2. Canalis sinosus -anterior superior alveolar nerve and
vessels
3. Tuberosity -groove for maxillary nerve
4. Incisive canal-nasoplalatine nerve and greater palatine
artery
5. Greater palatine foramen –greater palatine nerve and
vessels
6. Alveolar canals on posterior wall of sinus- posterior
superior alveolar nerve and vessels

ARTICULATIONS
1. 1. Frontal
2. 2. Ethmoid
3. 3. Nasal
4. 4. Zygomatic
5. 5. Lacrimal
6. 6. Inferior Nasal Choncha
7. 7. Palatine
8. 8. Vomer
9. 9. Opposite Maxilla

POTENTIAL SPACES OF INFECTION
INFLUENCED BY THE MUSCLE
ATTACHMENTS
 DENTO ALVEOLAR ABSCESS
 VESTIBULAR ABSCESS
 PALATAL ABSCESS
 CANINE SPACE INFECTION
 BUCCAL SPACE INFECTION
 INFRA ORBITAL SPACE INFECTION
 INFRA TEMPORAL SPACE INFECTIONwww.indiandentalacademy.com

MUSCLE ATTACHMENT

Maxilla

It is roughly pyramidal
and encloses maxillary
sinus. The base of the
pyramid is formed by
the nasal surface and
the apex is directed
towards the zygomatic
process

It has 4 surfaces:
• Anterior/facial surface :
• Posterior/infra temporal:
• Superior/orbital surface :
• Medial/nasal surface :

1.Anterior Surface: Faces antero-laterally and
displays inferior elevations. Overlying the roots of teeth.
It presents:-
•Incisive fossa – shallow depression above the sockets of
incisors. where depressor septi is attached,orbicularis oris
attached below,and superiolaterally nasalis.
•Canine fossa – Deeper depression lateral to incisive
fossa but separated from it by canine eminence which
corresponds to socket of canine.Levatorangulioris muscle
is attached

Infra-orbital Foramen:
Lies above the canine
fossa.
It transmits the infra
orbital vessels and
nerve.

Medially the anterior
surface ends at a deeply
concave nasal notch,
which ends in a pointed
bony projection called
anterior nasal spine.

2.Posterior (Infra-temporal) surface:
It is concave and faces postero-laterally, forming the
anterior wall of infra-temporal fossa and is separated from
the anterior surface by maxilla’s zygomatic process and a
ridge ascending to it from the 1st
molar socket.
It presents:
•Foramina of alveolar canals near the center of surface
transmitting posterior superior alveolar vessels and nerves.
•Maxillary tuberosity – postero-inferiorly.
•Forms the anterior boundary of pterygopalatine fossa.www.indiandentalacademy.com

Opening of alveolar
canal
Tuberosity

3.Superior (orbital) surface:
Smooth, roughly triangular and slightly concave
forming greater part of floor of orbit.
Anterior border – forms inferior margin of orbital opening.
Posterior border – forms greater part of anterior margin of
inferior orbital fissure.
Medial border – separates it from nasal (medial) surface.
It presents lacrimal notch anteriorly.
Infraorbital groove and canal – transmits infra-orbital
vessels and nerve.www.indiandentalacademy.com

4.Medial/Nasal surface –
Forms greater part of
lateral wall of nasal cavity.
It presents:
Maxillary hiatus - a large
irregular opening leading
into maxillary sinus.

It has 4 processes
•Zygomatic process:
•Frontal process :
•Alveolar process :
•Palatine process :

1.Zygomatic process:
It is a pyramidal
projection where anterior,
infra temporal and orbital
surfaces converge.
• It articulates with the
maxillary process of
zygomatic bone.www.indiandentalacademy.com

2.Frontal process:
It projects postero-superiorly
between the nasal and lacrimal
bones.
•The frontal process apically joins
with the nasal notch of frontal bone
at fronto -maxillary suture.
•Anterior border articulates with
lateral border of nasal bone and the
posterior with lacrimal bone.

3.Alveolar process:
SSS
It is thick and arched
and projecting
downward and
socketed for tooth
roots.
•With its fellow of
opposite side forms

• Form posterior 1/3 of
hard palate
• L shaped with horizontal
and perpendicular plates
• The horizontal plates
articulate
• with the posterior
serrated border of
palatine process of
maxilla the horizontal
plates unite to form
posterior nasal spine
4.Palatine process:

Maxillary sinus (Antrum of Highmore):
The body of maxilla is occupied by large air
cavity the maxillary sinus which is a hollow
pyramidal and has thin walls (corresponding to
orbital, alveolar, facial and infra temporal aspects
of maxilla). The apex directed laterally into the
zygomatic process; its base medially to the lateral
wall of the nasal cavity.

Its posterior wall contains alveolar canals for
posterior superior alveolar vessels and nerve to
molar teeth.

Its floor is formed by alveolar process. Its
lowest part is below the nasal floor & is lined
by respiratory epithelium.
Maxillary sinus opens into the middle meatus
through hiatus semilunaris.
The function of maxillary sinus is considered to
be to lighten the weight of skull and for
resonance of voice.

MAXIARY SINUSMAXIARY SINUS

PYRAMIDAL CAVITY
BOUNDED BY FACIAL,ORBITAL,ALVEOLAR AND INFRA
TEMPORAL ASPECTS
APEX IS LATERAL AND EXTENTS IN TO ZYGOMATIC
PROCESS
BASE IS MEDIAL AND FORMS LATERAL WALL OF NASAL
CAVITY DISPLAYING MAX HIATUS

OPENING OF SINUS IN TO LATERAL
WALL OF NASAL CAVITY

CONNECTIONS OF MAXILLARY SINUS

SURGICAL ANATOMY
SINUSITIS
CARSINOMA OF MAX SINUS >>>THIN
WALL>>PERFORATIONS TO ALL BOUNDARIES
# OF SINUS WALLS
COMPLICATIONS DURING ORBITAL FLOOR #
ORO ANTRAL FISTULAS/COMMUNICATIONS
CALD WELL LUC OPERATIONS
OSTIUM OPENING POSITION >>DRAINAGE
NASAL ANTROSTOMY
OSTEOMYELITIS

ARTERIAL SUPPLY

AGE CHANGES IN MAXILLA

1) AT BIRTH :
-The transverse and antereo-posterior(sagital)
diameter are more than the vertical diameter.
-Frontal process is more prominent
-Body portion more than alveolar process,
-The alveoli reaching almost to the floor of the
orbit.
- Maxillary sinus is mere farrow on the lateral
wall of the nose.

2) IN THE ADULT:
Vertical diameter is greatest due to
development of the alveolar process and
increase in the size of the sinus.

As the age advances the size of sinus also
increases.
The floor or sinus is very nearer to the roots of
molars.
So there are more chances of accidental exposure
of maxillary sinus during extraction of maxillary
molars.

3) IN THE OLD :
The bone reverts to infantile condition its
height is reduced as a result of resorption of
alveolar process.

Maxillary Sinus.

Incisive
foramen.

Median palatal suture.

Nasal fossae.

Maxillary tuberosity

Coronoid process of the mandible.

Zygomatic process of maxilla

OSTEOLOGYOSTEOLOGY
OFOF
MANDIBLEMANDIBLE

The mandible from Latin mandibula-
"jawbone" or inferior maxillary bone, the
largest and strongest bone of the face .It forms
the lower jaw and holds the lower teeth in
place.

It is the only movable bone in the skull.
It provides structure and protective support
for the oral cavity.
The mandible is articulated in ball-and-
socket fashion at the condylar process.
Strength resides in its dense cortical plates.

The cortical bone is thicker anteriorly and at the
lower border of the mandible, while posteriorly
the lower border is relatively thin.
The cancellous bone of the body forms, a loose
network frequent large bone-free spaces.
Thus mandible is strongest anteriorly in midline
with progressively less strength towards condyle.

OSSIFICATION OF MANDIBLE
Second bone to ossify in the body.
Intramembranous ossification.
Only small part of meckel’s cartilage some
distance from midline is site of Endochondral
ossification.
Each half ossifies from one centre which appears
in 6th
week of intra uterine life, near future
mental foramen.
In fetal life it is a paired bone
Bony union takes place during first year of life at
symphysis menti.

MANDIBLE:
- It has a horse shoe shaped
body which lodges teeth
- A pair of Rami which projects
upwards from the posterior ends
of the body and provides
attachment to jaw muscles.

BODY OF THE MANDIBLE
U-shaped BODY
Has two surfacesEXTERNAL and INTERNAL
surfaces ,
Two borders UPPER and LOWER borders.

EXTERNAL SURFACE
1. Symphysis menti
2. Mental protuberance
3. Mental foramen
4. External oblique line
5. Incisive fossa
1
4

INTERNAL SURFACE
1. Mylohyoid line
2. Submandibular fossa
3. Sublingual fossa
4. Genial tubercles
5. Mylohyoid groove
6. Upper alveolar
border
7. Lower border /base
8. Mandibular tori
maybe present

TWO BORDERS.
SUPERIOR
BORDER
(ALVEOLAR BORDER)
It is hollowed into
cavities for the
reception of the
teeth. these cavities
are sixteen in
number, and vary in
depth and size
according to the teeth
which they contain.www.indiandentalacademy.com

INFERIOR BORDER
is rounded, longer than
the superior, and
thicker in front than
behind.

 Is quadrilateral
 2 surfaces2 surfaces
1. Lateral
2. Medial
 4 borders4 borders
1. Upper
2. Lower
3. Anterior
4. Posterior
 2 processes2 processes
1. Coronoid
2. Condylar
RAMUS OF MANDIBLE

 Lateral surfaceLateral surface – flat
with oblique ridges
 Medial surfaceMedial surface –
Features-
1. Mandibular foramen
2. Lingula
3. Mylohyoid groove
4. Upper border-forms
mandibular notch
5. Lower border- forms
angle( junction of the
body and ramus )


BORDERS OF RAMUS:-
The lower border of the ramus is
thick, straight, and continuous with
the inferior border of the body of
the bone. At its junction with the
posterior border is the angle of the
mandible, and is marked by rough,
oblique ridges on each side, for the
attachment of the Masseter
laterally, and the Pterygoideus
internus medially; the
stylomandibular ligament is
attached to the angle between these
muscles.

The upper border is thin,
and is surmounted by two
processes, the coronoid in
front and the condyloid
behind, separated by a
deep concavity, the
mandibular notch.

AnteriorAnterior border-
continuous with
coronoid process
PosteriorPosterior border-
extends from
condyle to angle
AB

Coronoid process
Flat ,triangular
Upward and
forward projection
from anterolateral
part of ramus
Anterior border
continuous with
anterior border of
ramus
Posterior border
bounds the
mandibular notchwww.indiandentalacademy.com

Condylar process
Upward projection from
postero superior part of
ramus
Apically enlarged as head
of condyle.
Articulates with temporal
bone’s mandibular fossa
to form
temperomandibular joint
Lateral aspect palpable in
front of tragus
Pterygoid fovea anterior
to neck www.indiandentalacademy.com

ATTACHMENTS AND RELATIONS
1. External oblique- origin to
buccinator,depressor inferioris,
depressor anguli oris
2. Incisive fossa -origin of
mentalis, mental slips of
orbicularis oris
3. Mylohyoid line – origin to
mylohyoid muscle , attachment
to superior constrictor of
pharynx, pterygomandibular
raphae
4. Upper genial tubercles
-genioglossus

5. Lower genial tubercles –
origin to geniohyoid
6. Diagastric fossa- anterior
belly of diagastric
7. Lower border -deep
cervical fascia and
platysma
8. Lateral surface of ramus -
insertion for masseter
9. Posterosuperior lateral
surface of ramus-parotid
gland

10. Lingula-sphenomandibular
ligament
11. Medial surface of ramus-medial
pterygoid muscle attachment
12. Apex of coronoid process -
temporalis attachment
13. Pterygoid fovea - lateral
pterygoid muscle
14. Lateral surface of neck -
attachment to lateral ligament of
temperomandibular joint ,
parotid gland

Arterial supply
Internal maxillary artery from the external carotid
Inferior alveolar artery through the mandibular
foramen
Mental artery through the mental foramen

1. Mental foramina - mental
nerve and vessels
2. Mandibular notch -
massetric nerve and vessels
3. Medial side of neck -
auriculo temporal nerve
4. Mylohyoid groove -
mylohyoid nerve and vessels
5. Mylohyoid groove in front
of ramus - lingual nerve
FORAMINA AND OTHER RELATIONS

 Mandibular canal and
foramina - inferior
alveolar nerve and
vessels
 Parotid gland
Articulation
 Temporals – 2
(Temperomandibular joint)

AGE CHANES IN MANDIBLE
(Henry Gray (1821–1865). Anatomy of the Human Body. 1918.)

The body of the bone is a mere shell,
containing the sockets of the two incisor, the canine, and the two
deciduous molar teeth, imperfectly partitioned.
The mandibular canal is of large size,
and runs near the lower border of the
bone;
The mental foramen opens beneath
the socket of the first deciduous molar
tooth.
The angle is obtuse (175°),
condyloid portion is nearly in line with the body.
The coronoid process is of comparatively large size, and projects
above the level of the condyle.
AT BIRTH

Two segments of the bone become joined at the symphysis.
The body becomes elongated in its whole length, but more especially
behind the mental foramen, to provide space for the three additional
teeth
Increased growth of the alveolar part,
to afford room for the roots of the teeth,
Thickening of the sub dental portion which
enables the jaw to withstand the powerful
action of the masticatory muscles;
The mandibular canal, is situated just above the level of the mylohyoid
line; and the mental foramen occupies the position usual to it in the
adult.
AFTER BIRTH

The alveolar and sub dental
portions of the body are usually of
equal depth.
The mental foramen opens
midway between the upper and
lower borders of the bone,
Mandibular canal runs nearly
parallel with the mylohyoid line.
The ramus is almost vertical in
direction, the angle measuring
from 110° to 120°.
In the adult

Bone becomes greatly reduced in size, with the loss of the
teeth the alveolar process is absorbed,
The chief part of the bone is below the
oblique line. In old age
The mandibular canal, with the
mental foramen opening
from it, is close to the alveolar border.
The ramus is oblique in direction, the angle measures about
140°,
Neck of the condyle is more or less bent backward.www.indiandentalacademy.com

Occulsal View
A- At birth
B- At 6 yrs
C- Adult

A – Mandible at birth
B – At 6 years Lateral View
C – In an Adult

Geni
al
tube
rcles
.

 Hereditary Disorders
 Infections and Fractures
 Metabolic Diseases
 Primary Bone Disease
 Bone Tumors

(1) AGNATHIA
Is an extremely rare congenital defect
characterized by absence of maxilla or mandible
commonly only a portion might be missing.

MICROGNATHIA
It literally means small jaw. Either the maxilla or
the mandible may by affected Sometimes the term
may be used due to absolute small size, but rather to
an abnormal positioning or relation of one jaw to the
other or the skill which produces illusion of
micrognathia. There micrognathia may be classified
as:
•Congenital
•Aequired

MACROGNATHIA
Means relatively large jaws.
It may be associated with:
• Paget's disease.
• Acromegaly owing to hyperpituitarism.
• Leontiasis ossea, a form of fibrous dysplasia.

FACIAL HEMIHYPERTROPHY

FACIAL HEMIATROPHY

EXOSTOSIS–
- Are localized bony protuberances that arise
from the cortical plate.
- These benign growths frequently affect both the
jaws.
- Torus mandibularis is a common exostosis that
develops along the lingual aspect of the mandible,
above mylohyoid .

The cause is
multifactorial, Including
both genetic.
prevalance ranges from
5% to 40%

LINGUAL CORTICAL MANDIBULAR DEFECT-
(Stafne defect, static bone cyst)
Seen more commonly in
anterior part of mandible in the
region of incisor, canine and in
premolar region, below
mandibular canal, represents a
focal concavity of the cortical
bone on the lingual surface of
the mandible.

Usually due to untreated
Dental caries, causing inflammation of
pulp.
Inflammation of cancellous bone and
connective tissue surrounding dental root
apices

MALIGNANT TUMORS

1. Odontogenic carcinomas

- Metastasizing (malignant) ameloblastoma
- Ameloblastic carcinoma (primary and secondary
type)
- Primary intraosseous squamous cell carcinoma
(solid, derived from KCOT and derived from
odontogenic cysts)
- Clear cell odontogenic carcinoma
- Ghost cell odontogenic carcinoma

2. Odontogenic sarcoma

- Ameloblastic fibrosarcoma
- Ameloblastic fibrodentino
- Fibro-odonto sarcoma

CHERUBISM
Hereditary and intraosseous
fibrous swellings of jaws.
Autosomal dominant.
Bilateral involvement of
mandible and maxilla in
young individuals.
Treatment: surgery may not
be indicatedwww.indiandentalacademy.com

COMPOUND ODONTOMA
Masses of small misshapen teeth (3-2000),
more differentiated than complex odontoma
Benign
Anterior jaw, usually maxilla
Xray images: mass above crown of
unerupted canine

Cysts of the jaws
are classified into two categories:
Odontogenic and Nonodontogenic.

HEREDITARY DISORDERS
›Osteogenesis imperfect
› Osteopetrosis
› Osteochondroma
› Achondroplaisa

METABOLIC DISEASES
›  Osteoporosis
›  Tensynovitis
›  Scurvy
›  Paget's Disease
›  Bone Changes in Hyperparathyroidism
›  Renal Osteodystrophy

INFECTIONS AND FRACTURES
›  Pyogenic osteomyelitis
›  [Hematogenous (Pyogenic) Osteomyelitis]
›  Tuberculosis
›  Osteomyelitis from a Contiguous Infection
›  Osteomyelitis from an Introduced Infection
›  Bone Tuberculosis
›  Bone Syphilis
›  Fungus Infections of Bonewww.indiandentalacademy.com

PRIMARY BONE DISEASE
›  Hypertrophic Osteoarthropathy
›  Fibrous Lesions
›  Cysts

BONE TUMORS
›  Plasma Cell Myeloma
›  Metastatic Disease
›  Osteogenic Lesions -- Benign
›  Cartilaginous Tumors
›  Bone-Forming Tumors
›  Tumors of Unknown Histogenesis
›  Miscellaneous Tumors and
› Tumor-like Lesions of Bonewww.indiandentalacademy.com

NONNEOPLASTIC DISORDERS OF BONE
›  Fibrous Dysplasia of Bone
›  Fibrous Cortical Defect and Nonossifying Fibroma
›  Solitary Bone Cyst (Unicameral Bone Cyst)
›  Aneurysmal Bone Cyst
›  Eosinophilic Granuloma of Bone
›  Bone Lesions of Gaucher's Diseasewww.indiandentalacademy.com

FIBRO-OSSEOUS LESIONS OF THE JAWS
1.FIBROUS DYSPLASIA
2.CEMENTO-OSSEOUS DYSPLASIA
3.OSSIFYING FIBROME

RIGHT MAXILLA: LATERAL ASPECT

A. Developmental

                                Primordial cysts
ODONTOGENIC   Gingival cyst of infants
    CYSTS                Eruption cysts
                                Dentigerous cyst (follicular)
                                Gingival cyst of adults
                                 Lateral periodontal cyst www.indiandentalacademy.com

Radicular Cyst

Residual Cyst

Paradental Cyst

Dentigerous Cyst

Developmental Lateral Periodontal
Cyst

Odontogenic Keratocyst

Glandular Odontogenic Cyst

Nonodontogenic Cysts

Incisive Canal Cyst

Stafne Bone Cyst

Traumatic Bone Cyst

Odontogenic Tumors

Ameloblastoma

Calcifying Epithelial Odontogenic
Tumor

Adenomatoid Odontogenic Tumor

Cementoblastoma

Central Giant Cell Granuloma

Fibrous Dysplasia

Ossifying Fibroma

Condensing Osteitis

When patient is subjected to injury, there is
chance that jaws may be fractured Even in some
cases minor trauma may result in bone damage.
MOST COMMON CAUSES

• Road traffic accidents

• Assault, falls sport injury etc.,

MAXILLARY FRACTURES
Accounts for 46% of facial fractures
FRACTURES SITES IN MAXILLA
DENTOALVEOLAR FRACTURES: Alveolar process of
maxilla is more common than mandible in the region of
incisors, cuspid and tuberosity
LEFORT I : low level fracture, where there is bilateral
detachment of alveolar process of maxilla

LEFORT II: involving the frontal process of maxilla
LEFORT III: involving the frontal process of maxilla

Fracture of mandible occurs more frequently
than Maxilla.
fracture of mandible - 61 %

CLASSIFICATION
According to type of fracture

• Simple-it includes closed linear fracture like Green stick
fracture seen in children

• Compound-fracture of alveolar process of jaws with
severe injuries the overlying skin.


• Comminuted-
compound fracture further complicated by bone and
soft tissue loss.

• Pathological-when fracture result from minimum
trauma to jaws which is already weakened by
pathological condition like osteomylitis ,neoplasms.

common sites of fractures in mandible
•Dent alveolar -3%
• Condyle -36%
• Coronoid -2%
• Ramus -3%
• Angle -20%
• Body (molar and premolar)
-21%
• Parasymphysis -14%
• Symphysis -1%www.indiandentalacademy.com

Soft tissue laceration-soft tissue wound should be
sutured within 24 hours of injury.
Antibiotics-benzyl penicillin should be administered 1M
injection or 1 mega unit every 6 hours for first 2 to 3 days
and oral penicillin should be continued for 1 further week.
In recent oral metronidazole 400 to 800 mg BO is given to
all patients with mandibular fracture.


Reduction-reduction of fracture means the restoration of
functional alignment of bone fragments.
 Immobilization of fractured bone-the fracture site must be
immobilized to allow bone healing to occur. lmmobilization
can be done with intermaxillary fixation and bone plating.

 B.D. Chaurasia. -Human Anatomy, Regional and Applied.
2005; vol 3
 Antonio Nanci, Tencate. -Oral Histology.
2006; 6th
edition
 Anil Govinda Rao Ghom. -Text Book of Oral Medicine.
2005; 1st
edition
 D. Vincent Provenza. - Oral Histology, Inheritance and
development.
1986; 2nd
edition
 Warren .H. Lewis. –Gray’s Anatomy of the Human Body.
2000; 20th edition

 James.K.Avery. –Essentials of Oral Histology and
Embryology-A Clinical approach.
2000; 2nd
edition
James.K.Avery. –Oral Development and Histology.
2002; 3rd
edition
D. Vincent Provenza. - Oral Histology, Inheritance and
development.
1986; 2nd
edition
R.N. Bajpai -Human osteology,
1986 1st
edition
 Inderbir Singh- Text book of human histology.
4th
edition
WWW.GOOGLE.COM - FOR PICTURESwww.indiandentalacademy.com

Extension of meckel’s cartilage on either side
FROM AM J ANT, 167:495,1983

Spread of mandibular ossification away from meckel’s cartilage at lingula

Trabecular bone and compact bone in the body of the mandible
Tooth apex
Cancelous bone
Compact bone

MANDIBULO FACIAL DYSOSTOSIS
•It is a rare syndrome characterized by defect of sturctures
derived from 1st
and 2nd
brachial arch
•Mandible is underdeveloped
resulting in marked retruded chin.
•Facial reconstruction with
cosmetic surgery and
orthognathic surgery. www.indiandentalacademy.com

HEMIMAXILLOFACIAL
DYSPLASIA
•Recently recognized
developmental disorder that
affects the jaws.
•There may be unilateral
enlargement of maxillary
bone along with fibrous
hyperplasia of overlying
soft tissue.www.indiandentalacademy.com

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