Anatomy of maxilla and mandible

Anatomy of maxilla and mandible
Submitted by:
Samidha
Pg student
Department of Prosthodontics
Submitted to:
Dr. Sarabjit kaur
Associate Professor
Department of Prosthodontics

Contents
• Introduction
• Anatomy of mandible
• Age changes of
mandible
• Prosthodontic
consideration of
anatomy of mandible
• Anatomy of maxilla
• Age changes in maxilla
• Prosthodontic
consideration of
anatomy of maxilla
• Conclusion
• Reference

Introduction
The maxilla is the most important bone of the midface. It
has a central location and provides structural support to
the viscerocranium. It has functional and aesthetic
significance as it has a fundamental role in facial
architecture.
The mandible is the largest bone in the human skull. It
holds the lower teeth in place, it assists in mastication
and forms the lower jawline. Other than the ossicles of
the ear, the mandible is the only skull bone that is
mobile, allowing the bone to contribute to masticatio

• The study of anatomy of maxilla and mandible is very important in
dentistry as they support the dentures and govern the impression
making procedures , tooth position in denture and contours of
finished dentures.
• The study of head form in man has always been of considerable
interest to anthropologist, anatomist and other students.
• The dentist must be fully understand the anatomy of maxilla and
mandible’s supporting and limiting structure, for the design of
appropriate prosthesis and for selective placement of force as
determined by stress bearing areas.

Anatomy of mandible
• Mandible is largest and strongest bone of the
face.
• It develops from 1st pharangeal arch.
• It has horseshoe shape body which lodges the
teeth, and pair of rami which project upward
from posterior ends of body.
• Rami provise attatchment to muscle of
mastication.

Body of mandible
It has external and internal surfaces seprated by upper
and lower borders

External surface
The outer surface presents the following features:
1. Symphysis menti
2. Mental protubarance
3. Mental foramen
4. External oblique ridge
5. Incisive fossa

Internal surface
The inner surface presents the following features:
1. Mylohyoid line
2. Submandibular fossa
3. Sublingual fossa
4. Genial tubercles
5. Mylohyoid groove
6. Upper alveolar border

Ramus
• It is quadrilateral in shape.
• It has 2 surfaces : Medial
Lateral
• Four borders :Upper
Lower
Anterior
Posterior
• Four Process : Coronoid
Condylar

• Lateral surface-flat and bears a number of oblique ridges.
• Medial surface-
Mandibular foramen- The mandibular foramen lies a little
above the centre of ramus at the level of occlusal surfaces
of the teeth. It leads into the mandibular canal which
descends into the body of the mandible and opens at the
mental foramen.
The anterior margin of the mandibular foramen is marked
by a sharp tongue-shaped projection called the lingula.
The mylohyoid groove begins just below the mandibular
foramen and runs downwards and forwards.

• Upper border- is thin and curved and forms
mandibular notch
• Lower border- forms angle , junction of body and
ramus.
• Anterior border- continuous with coronoid process.
• Posterior border- extends from condyle to angle.

Coronoid process
• The coronoid process is a flattened triangular upward
projection from the anterosuperior part of the ramus.
• Anterior border continuous with anterior border of
ramus
• Posterior border bounds the mandibular notch

Condylar process
• Upward projection from posterosuperior part of
ramus.
• Upper end is expanded from side to side to form the
head , head is covered by fibrocartilage.
• Articulate with temporal fossa and forms
temperomandibular joint.
• The constriction below the head is neck, depression on
its anterior surface is called pterygoid fovea.
• Lateral aspect is palpable in front of tragus.

Muscles Attachments and
relations
• External oblique ridge-origin to buccinator,
depressor labi inferioris,depressor anguli oris
• Incisive fossa-origin of mentalis
• Mylohyoid ridge- origin of mylohyoid muscle,
attachment to superior constrictor of pharynx,
pterygomandiular raphae
• Upper genial tubercle- genioglossus
• Lower genial tubercles- origin of geniohyoid

• Diagastric fossa- anterior belly of diagastic
• Lower border- deep cervical fascia and platysma
• Lateral surface of ramus – insertion for masseter
• Lingula – sphenomandibular ligament
• Medial surface of ramus- medial pterygoid muscle
attachment
• Apex of coronoid process- temporalis attachment
• Pterygoid fovea- lateral pterygoid muscle

Blood Supply and Lymphatics
• Blood supply to the mandible is via small periosteal and endosteal
vessels. The periosteal vessels arise mainly from the inferior alveolar
artery and supply the ramus of the mandible. The endosteal vessels
arise from the peri-mandibular branches of the maxillary artery, facial
artery, external carotid artery, and superficial temporal artery; these
supply the body of the mandible. The mandibular teeth are supplied
by dental branches from the inferior alveolar artery.
• Lymphatic drainage of the mandible and mandibular teeth are
primarily via the submandibular lymph nodes; however, the
mandibular symphysis region drains into the submental lymph node,
which subsequently drains into the submandibular nodes.

Nerves
The main nerve associated with the mandible is the inferior
alveolar nerve, which is a branch of the mandibular division
of the trigeminal nerve. The inferior alveolar nerve enters the
mandibular foramen and courses anteriorly in the mandibular
canal where it sends branches to the lower teeth and
provides sensation. At the mental foramen, the inferior
alveolar nerve branches into the incisive and mental nerve.
The mental nerve exits the mental foramen and courses
superiorly to provide sensation to the lower lip. The incisive
nerve runs in the incisive canal and provides innervation to
the mandibular premolar, canine, and lateral and central
incisors.

Foramina And Relations To Nerves and Vessels
• Mental foramen- mental nerve and vessels
• Mandibular foramen- inferior alveolar nerve and vessels
• Mandibular notch- massetric nerve and vessels
• Medial side of neck of condyle – auriculotemporal nerve
and superficial temporal artery.
• Mylohyoid groove- mylohyoid nerve and vessels, lingual
nerve.

Age changes in Mandible
• In infants and children:-
1.The two halves of the mandible fuse during the first
year of life.
2.At birth , the mental foramen opens below the sockets
for the two deciduous molar teeth near the lower
border, this is so because the bone is made up only of
the alveolar part with teeth sockets.
3.The mandibular canal runs near the lower border.
4.The angle is obtuse , it is 140 degrees or more because
the head is in line with the body.
5. The coronoid process is large and projects upwards
above the level of the condyle.

• In adults:-
1.The mental foramen opens midway between the
upper and lower border because the alveolar and
subalveolar parts of the bone are equally
developed.
2.The mandibular canal runs parallel with mylohyoid
line.
3.The angle reduces to about 110 or 120 degrees
because ramus becoms almost vertical.

• In old age:-
1.Teeth fall out and the alveolar bone is resorbed, so that
the height of body is markedly reduced.
2.The mental foramen and the mandibular canal are close
to alveolar border.
3.The angle again becomes obtuse about 140 degrees
because the ramus is oblique.

Clinical consideration
• Distobuccal flange of maxillary denture should not
overfill the vestibule , since when mandible is
protruded the anterior border of ramus extends
towards the tuberosity and causes discomfort and
dislodgement.
• External oblique line guide for lateral termination
of buccal flange of mandibular denture.
• Buccal shelf area is the primary stress bearing area
because its density , mucosal covering , relation to
vertical closure of jaws is best suitd to resist forces
on it.

• When the ridge resorption is extensive mental
foramen is in a more superior position and hence
must be relieved
• Resorption pattern makes the mandible wider and
larger and inclines outward

• It is the second largest bone of the face.
• It also contributes to the formation of
1. Floor of the nose and the orbit
2. Roof of the mouth
3. Lateral wall of the nose
4. Pterygopalatine and infratemporal fossae
5. Pterygomaxillary and infraorbital fissures
• Maxilla articulates superiorly with three bones, the
nasal, frontal and lacrimal.
• Medially, it articulates with five bones, the ethmoid,
inferior nasal concha, vomer, palatine and opposite
maxilla.
• Laterally, it articulates with zygomatic bone.
Maxilla

The anatomy of maxilla has two main parts :
1. Body
a) Anterior or facial surface
b) Posterior or infratemporal surface
c) Superior or orbital surface
d) Medial or nasal surface
2. Processes
a) Zygomatic
b) Frontal
c) Alveolar
d) Palatine
Anatomy of maxilla

• Anterior or Facial Surface:- is directed forward and
laterally.
• Structures present on anterior structure :–
a) Incisive fossa
b) Canine fossa
c) Canine eminence
d) Infraorbital foramen
e) Anterior nasal spine
f) Nasal notch

• Posterior or lnfratemporal Surface:- it is directed
backwards and laterally.
• It forms anterior wall of infratemporal fossa.
• Near the centre of the surface open two or three
alveolar canals for posterior superior alveolar nerve and
vessels.
• Posteroinferiorly, there is rounded eminence in the
maxillary tuberosity ,which articulates superomedially
with pyramidal process of palatine bone and gives origin
laterally to the superficial head of medial pterygoid
muscle.

•Superior or orbital surface -
• It is smooth, triangular and slightly concave and forms
the greater part of the floor of orbit.
• Anterior border forms a part of infraorbital margin .
Medially , it is continous with the lacrimal crest of the
frontal process.
• Posterior border is smooth and rounded , it forms most
of the anterior margin of inferior obital fissure. In the
middle , it notched by the infraorbital groove.
• Medial border presents anteriorly the lacrimal notch
which is converted into nasolacrimal canal by the
descending process of lacrimal bone. Behind the notch,
the border articulates from before backwards with
lacrimal , laybinth of ethmoid and the orbital process of
palatine bones.

Mesial or nasal surface:-
• It forms a part of lateral wall of nose.
• Posterosuperiorly, there is a large maxillary hiatus which
leads into the maxillary sinus.
• Below the hiatus, the smooth concave surface forms a
part of inferior meatus of nose.
• Behind the hiatus, the surface articulates with
perpendicular plate of palatine bone, enclosing the
greater palatine canal which runs downwards and
forwards, and transmits greater palatine vessels and the
anterior, middle and posterior palatine nerves.

Palatine process:-
• It is thick, strong and horizontal plate projecting medially
from lowest part of medial maxillay aspect (nasal surface).
• Superior surface is concave side to side and forms greater
part of roof of mouth and floor of nasal cavity.
• lnferior surface is concave, and the two palatine processes
form anterior three-fourths of the bony palate.
• Medial border raised as nasal crest and terminate into the
anterior nasal spine
• Posterior border serrated to join with horizontal plate of
palatine bone
• Lateral border is continuous with the alveolar process.

Alveolar process :-
It arises from lower surface of maxilla
• It is thick and arched and wide behind with sockets of
teeth
• The eight sockets on each side vary according to the
tooth type.
• The socket for the canine is deepest, the socket for the
molars are widest and subdivided into three by septa,
those for incisors and second premolar usually divided
into two.
• Buccinator arises from the posterior the posterior part
of its outer surface upto the first molar tooth.
• A rough ridge, maxillary torus is sometimes present on
the palatal aspect of the process near the molar socket.

Zygomatic process :-
pyramidal projection , on
which anterior, infratemporal
and orbital surface converge.
Frontal process : it is strong
plate which projects upwards
posteriosuperiorly between
nasal and lacrimal bone.

• The socket is made of 2 types of bone-
1. Lamina dura[ alveolar bone proper]- lining wall of
socket
2. Supporting bone – inner and outer cortical plate
- trabecular bone

Maxillary sinus
• It is large pyramidal cavity, which corresponds to
orbital , alveolar, facial and infratemporal aspects of
maxilla.
• Average size - 25mm transversly , 30mm
anteroposteriorly and 30mm vertically
• Extent :–.
1. Apex: truncated and extends into zygomatic
process and sometimes zygomatic bone.
2. Base : is medial and lateral wall of nasal cavity with
the maxillary hiatus.

3. Roof : floor of orbit
4. Floor : alveolar process of maxilla, 1cm below level
of floor of nose and corresponds to level of ala of
nose.
5. Posterior wall : contains alveolar canals
6. Extension: The upper second premolar and first
molar are related to the floor of the sinus, but it
may extend anteriorly to the first premolar tooth.

Muscles Attachments and
relations
• Incisive fossa- depressor septi
• Canine fossa- levator anguli oris
• Infraorbital margin- levator labi superioris
• Tuberosity- fibers of medial pterygoid
• Lateral lacrimal groove – inferior oblique muscle
• Anterior lacrimal crest – medial palpebral ligament
• Frontal process- orbicularis occuli, levator labi
superioris aleque nasi
• Zygomatic process- origin of masseter
• Alveolar process- buccinator

Nerves
Innervation of the maxilla is via the maxillary nerve (V2).
V2 constitutes the second branch of the trigeminal nerve,
the fifth and largest cranial nerve. It has its origin at the
trigeminal ganglion and serves, principally, as a sensory
nerve. It exits through the foramen rotundum to enter the
pterygopalatine fossa where it gives off several branches.
Sensory innervation of the maxillary structures is provided
by several structures including the sphenopalatine
ganglion, the infraorbital, posterior superior alveolar ,
middle superior alveolar, anterior superior alveolar ,
palatine and nasopalatine nerves.

Blood Supply and Lymphatics
• Blood supply to the maxilla is via branches of the
maxillary artery. The maxillary artery is a terminal
branch of the external carotid artery.

Foramina And Relations To Nerves and
Vessels
• Infraorbital foramen- infraorbital nerves and vessels
• Canalis sinosus- anterior superior alveolar nerves
and vssels
• Tuberosity – groove of maxillary nerve
• Incisive canal – nasopalatine nerve and vessels
• Greater palatine foramen- greater palatine nerve
and vessels
• Alveolar canals on posterior wall of sinus –
posterior superior alveolar nerve and vessels

Articulation of maxilla
• Superiorly , it articulates with three bones , the
nasal, frontal and lacrimal bones
• Medialy , it articulates with five bones, the ethmoid
, inferior nasal concha, vomer , palatine and
opposite maxilla
• Laterally , it articulates with one bone , the
zygomatic bone

Age changes in maxilla
• At birth :-1. the transverse and anteroposterior
diameters are each more than the vertical diameter
2.Frontal process is well marked
3. Body consists of a little more than the alveolar
process, the tooth sockets reaching to the floor of
orbit
4.Maxillary sinus is a mere furrow on the lateral wall
of the nose

• In the adult:- vertical diameter is greatest due to
development of the alveolar process and increase in the
size of the sinus
• In the old :-the bone reverts to infantile condition , its
height is reduced as a result of resorption of alveolar
process

Clinical considerations
• Zygomatic alveolar crest – similar to buccal shelf
area of mandible as stress bearing area, but the
mucosal covering is thin and hence not considered
for the same, in some cases may be prominent and
requires relief.
• Alveolar tubercle- provides resistance against the
horizontal movements of the denture.
• Alveolar process- following tooth extraction it tends
to resorb which compromises the retention of the
dentures.

•The palatine process of maxilla and
horizontal plates of palatine bone resist
resorption and are the stress bearing areas
in maxillary denture
•Mid palatal suture- needs to relieved since
the mucosal covering is thin
•Incisive foramen- carries nasopalatine
nerves and vessels and exit perpendicular
to the palate and need to be relieved

Conclusion
Complete dentures are artificial substitutes for tissues that has
been lost, denture must replace the form of the tissues as
closely as posible. The dentist must fully understand the
anatomy of the supporting and limiting structures:
• For design of appropriate prosthesis.
• For selective placement of forces as determined by stress
bearing potential of anatomic structures.
• For the harmony of the denture and living tissues to coexist for
reasonable period of time.

References
• Textbook of human osteology by INDERBIR
SINGH,third edition
• McMinn's Color atlas- fourth edition
• B.D. CHAURASIA’S human anatomy head and neck
sixth edition
• Gray’s anatomy 36th edition WILLIAMS and
WARWICK

Anatomy of maxilla and mandible

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Anatomy of maxilla and mandible