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View this animation to see how a blow to the head may produce a contrecoup (counterblow) fracture of the basilar portion of the occipital bone on the base of the skull. Why may a basilar fracture be life threatening?

Facial bones of the skull

The facial bones of the skull form the upper and lower jaws, the nose, nasal cavity and nasal septum, and the orbit. The facial bones include 14 bones, with six paired bones and two unpaired bones. The paired bones are the maxilla, palatine, zygomatic, nasal, lacrimal, and inferior nasal conchae bones. The unpaired bones are the vomer and mandible bones. Although classified with the brain-case bones, the ethmoid bone also contributes to the nasal septum and the walls of the nasal cavity and orbit.

Maxillary bone

The maxillary bone    , often referred to simply as the maxilla (plural = maxillae), is one of a pair that together form the upper jaw, much of the hard palate, the medial floor of the orbit, and the lateral base of the nose (see [link] ). The curved, inferior margin of the maxillary bone that forms the upper jaw and contains the upper teeth is the alveolar process of the maxilla    ( [link] ). Each tooth is anchored into a deep socket called an alveolus. On the anterior maxilla, just below the orbit, is the infraorbital foramen. This is the point of exit for a sensory nerve that supplies the nose, upper lip, and anterior cheek. On the inferior skull, the palatine process    from each maxillary bone can be seen joining together at the midline to form the anterior three-quarters of the hard palate (see [link] a ). The hard palate    is the bony plate that forms the roof of the mouth and floor of the nasal cavity, separating the oral and nasal cavities.

Maxillary bone

This image shows the location and structure of the maxilla. A small image of the skull on the top left shows the maxilla in ochre yellow. A magnified view shows the detailed structure of the maxilla.
The maxillary bone forms the upper jaw and supports the upper teeth. Each maxilla also forms the lateral floor of each orbit and the majority of the hard palate.

Palatine bone

The palatine bone    is one of a pair of irregularly shaped bones that contribute small areas to the lateral walls of the nasal cavity and the medial wall of each orbit. The largest region of each of the palatine bone is the horizontal plate    . The plates from the right and left palatine bones join together at the midline to form the posterior quarter of the hard palate (see [link] a ). Thus, the palatine bones are best seen in an inferior view of the skull and hard palate.

Homeostatic imbalances

Cleft lip and cleft palate

During embryonic development, the right and left maxilla bones come together at the midline to form the upper jaw. At the same time, the muscle and skin overlying these bones join together to form the upper lip. Inside the mouth, the palatine processes of the maxilla bones, along with the horizontal plates of the right and left palatine bones, join together to form the hard palate. If an error occurs in these developmental processes, a birth defect of cleft lip or cleft palate may result.

Cleft lip is a common development defect that affects approximately 1:1000 births, most of which are male. This defect involves a partial or complete failure of the right and left portions of the upper lip to fuse together, leaving a cleft (gap).

A more severe developmental defect is cleft palate, which affects the hard palate. The hard palate is the bony structure that separates the nasal cavity from the oral cavity. It is formed during embryonic development by the midline fusion of the horizontal plates from the right and left palatine bones and the palatine processes of the maxilla bones. Cleft palate affects approximately 1:2500 births and is more common in females. It results from a failure of the two halves of the hard palate to completely come together and fuse at the midline, thus leaving a gap between them. This gap allows for communication between the nasal and oral cavities. In severe cases, the bony gap continues into the anterior upper jaw where the alveolar processes of the maxilla bones also do not properly join together above the front teeth. If this occurs, a cleft lip will also be seen. Because of the communication between the oral and nasal cavities, a cleft palate makes it very difficult for an infant to generate the suckling needed for nursing, thus leaving the infant at risk for malnutrition. Surgical repair is required to correct cleft palate defects.

Questions & Answers

how is speech controlled by the nervous system?
Joseph Reply
The broca's area
Udebuana
chemical level cellular level tissue level organ level organ system level organism
Chidera Reply
Yes Yes because they can perform more than one activity in the body
Chidera
the functional and structural unit of the body
Chidera
A group of 2 or more tissue that come together to perform a specific function
Chidera
A group of organs that work together to perform a specific function or meet the physiological needs of the body
Chidera
It's the highest level of organization
Chidera
2 or more cells coming together to perform a specific function
Chidera
Skeletal muscles can be tetanized but not cardiac muscle.Discuss
Okeke Reply
what is regional anatomy?
Grace Reply
study of structures that contribute to specific body region
charles
what is human anatomy?
Sam
what is grey matter
OJO Reply
What is neuron cell
Dev Reply
neuron cell are the fundamental units of the brain and nervous system responsible for receiving sensory input from the external world, for sending motor commands to muscles and for transforming and relaying the electrical signals at every step in between
Serphine
What is the perfect defination of Life
Dev
What does a word muscles means ?
Abubakar
what is Anatomy
Hannah Reply
because she's not yet at term
Nansi Reply
what is physiology?
Grace Reply
what is physiology
David
Physiology is the study of the functions of the human body
Hannah
am a new one!!
sekela
what is Homeopathy
AHMED
Name three reasons to study anatomy and physiology
Hills Reply
To know more about our body structure and functions this helps us To know disorders easily To get the medicine To appriciate the structure with the system and know that we are unique creatures
Tinbit
Why do we need to study anatomy and physiology
Hills Reply
I want to study human anatomy
Ibrahim
What is anatomy
Christabel Reply
anatomy is the branch of medicine in which we study structure and part of the body
Ansar
The art of studying the different parts of any organized body, to discover their situation, structure, and economy; dissection.
ChristMas
anatomy is the study of structures that make up the body and how they re realated to each other
BRIAN
Anatomy is the study of structures of the body and shape of the body and body parts and their relationship to one another.
Abubakar
what is the importance of anatomy
Emeria Reply
cockroch ka sir katne ke bad o jinda kyu rahta
Anil
it helps us to understand the function of human metabolic system and also who these systems works which system play what role and so on
Nouman
It's help us to know the structure, functions and relationship of the human body
Nansi
it helps us to appreciate how the internal structures works
Damilola
Anatomy opens up to us the structures of the various parts of the human body and correlates them to their specific function respectively
Michael
Anatomy is helps us understand and explore much about human structures
Chuks
systemic anatomy in short
Puja Reply
systemic circulation is the circulation in which heart supplies oxygenated blood to cells of body and takes deoxygenated blood away from body to heart
Ajeet
really?
Puja
yeah
BRIAN
ha ji
Ajeet
well much setisfy
Nouman
hello
Limpo
am new here
Limpo
ok
Emeria
am new here
Sindazi
I'm new as well
Crystal
who ask the question about cockroach cutting head
Nouman
the answer is They have an open circulatory system, which there's much less pressure in.After you cut their heads off very often their necks would seal off just by clotting," he adds. "There's no uncontrolled bleeding.The hardy vermin breathe through spiracles, or little holes in each body se
Nouman
does this platform helpful
Sindazi
well it's up-to you how you utilities this
Nouman
thnx ajeet
Puja
hello
AKARAJ
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AKARAJ
I think it is helpful
Alfred
Hi
Christabel
hi
Sachin
how do plateletes function in blood clotting
lydia
it's the study of the systems of the body & how they work
Chidera
Please you can say me how to study very easy anatomy book? ?
Juna
hello
Danso
I want to know how to study Anatomy test book
Danso
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Fariha
well conversations
Noor
what are the function of the cell membrane
Elias Reply
the cell membrane helps in allowing and removing substances from the cell. it also aid in protecting the cell and giving it a definite shape.
veezy
The cell membrane is made up of a semipermeable lipid bi-layer which helps to regulate the kind of materials that enters it through active transport and passive diffusion.
Michael

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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