The Maxillae are a pair of large pyramidal bones
which make up the entirety of the upper jaw.
They contribute to the formation of the majority of the floor
and the lateral wall of the nasal cavities
as well as the floor of the orbital cavities.
Similar to our discussion of the previous zygomatic bone,
we should divide the Maxilla into parts.
Anatomically, the maxilla has:
A body: And the body has four surfaces, these are the Anterior,
Infratemporal or Posterior, Orbital and Nasal surfaces.
It also has four processes, namely:
the zygomatic, frontal, alveolar and palatine.
Let's commence our discussion with the body of the maxilla and its various surfaces.
The body of the maxilla is roughly triangular.
And as mentioned in the
previous slide has several surfaces.
Let's take a closer look at these surfaces and see
what anatomic landmarks are located within each.
The anterior surface is quite broad, and
there are several notable structures located here.
We have the incisive and the canina fossa.
We have the infraorbital
foramen, the infraorbital margin
which is the superior border of the anterior
surface, and this margin acts as a line of demarcation
between it in the orbital surface of the maxilla.
Medially, there is a concave nasal
notch and anterior to it the nasal spine
which is formed when two pointed
processes of the two maxillae come together.
Lastly, the anterior surface of the maxilla
offers attachment to several muscles of the face,
such as the orbicularis oris,
levator anguli oris, nasalis, etcetera.
The infratemporal surface is located
posterolateral to the anterior surface.
The point of separation between
them is a line that can be drawn down
from the zygomatic process of the maxilla.
This surface also has several notable
points which include the alveolar canals,
which transmit posterior alveolar vessels
and nerves and the maxillary tuberosity,
which is the site of articulation with the
pyramidal process of the palatine bone,
as well as a site of attachment for several
fibers of the medial pterygoid muscle.
The orbital surface is smooth and triangular.
It forms most of the floor the orbital cavity.
Important anatomic landmarks on the
orbital surface include the lacrimal notch,
which along with the ethmoid and palatine
bones forms the opening the nasal lacrimal duct,
the anterior edge of the inferior orbital fissure which
is formed by the posterior edge of the orbital surface,
the infraorbital groove which lies
centrally and obliquely descends,
opening up as the infraorbital foramen.
This allows the passage of the
infraorbital vessels and nerve.
And the last surface is the nasal surface.
This surface is located on the
anterior and medial side of the maxilla.
It contributes to the formation
of the lateral wall, the nasal cavity
and features the following anatomic landmarks;
superiorly the nasal surface features a maxillary
hiatus which is the opening for the maxillary sinus.
Aterior to the hiatus is a lacrimal groove which
contributes to the formation of the nasal lacrimal duct.
Below the nasal surface is concave and
corresponds to the inferior nasal concha.
more anteriorly a conchal crest is present
where the inferior nasal concha attaches.
The posterior area, the nasal surface is
rough and articulates with the palatine bone.
Here a greater palatine groove for vessels
and nerves of the same name is present.
This concludes our discussion of
the maxillary body and its surfaces
and now we move on to the various
processes of the maxillary bone.
Maxillary processes are points of
articulation with its surrounding bones.
As I mentioned previously,
there are four such processes.
The first of these processes is a zygomatic process.
Through this middle shaped projection, the
maxilla articulates with the maxillary process
of the zygomatic bone.
Second is the frontal process.
This process extends posterosuperiorly and
joins with the nasal surface of the frontal bone.
Additionally, the frontal process also
contributes to the formation of the ocular margin,
the lacrimal fossa and to the closure of some of
the ethmoidal air cells that we talked about before.
Third is the alveolar process.
This process is socketed to house
the roots of the upper teeth.
The fourth and the last
process is the palatine process.
The Palatine process is a thick, flat shelf that
contributes to the formation of the nasal floor
as well as the osseous hard palate
when it joins with its contralateral half
and the horizontal plate of
the palatine bone posterior.
Through the palatine process
pass many neurovascular foramina
which permit the passage of
various vessels and nerves.
Most significant of these foramina are
the incisive fossa and the palatine groove.
These allow for the passage of the greater
palatine artery and the nasal palatine nerve
into the nasal cavity