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Mandibular Anatomy

الكلية كلية طب الاسنان     القسم جراحة الوجة والفكين     المرحلة 2
أستاذ المادة ايمن حميد عريبي التميمي       30/12/2018 06:57:32
Introduction
The material in this program has been divided into maxillary and mandibular features. First time learners of this material may prefer to read through the textual material in sequence while clicking on highlighted text to view anatomic features and illustrations. Students who are already familiar with radiographic anatomy and who wish a quick review of radiographic features may find the alphabetic lists that can be accessed from the menu in the frame on the left to be a more efficient way to review material. Additional views may be seen and feature descriptions may be reviewed by clicking on the image and then clicking on the desired highlighted term.
Objectives
As you explore this program, keep the following objectives in mind. After completing the material you should be able to:
• Name normal anatomic structures labeled on an intraoral radiograph, and
• Point out or trace on an intraoral radiograph the anatomic structures named.
To help you review and make sure you ve met the program objectives, quizzes are included for you to test yourself.
Although this is a stand-alone exercise, it may be helpful for you to review text chapters on dental anatomy and the bones of the head to fully integrate the material into your knowledge of clinical anatomy. Material on dental anatomy and head and neck anatomy can be found in a number of sources including several web locations listed on the Other Web Resources page of this program.
Mandibular Anatomy
To understand this part of the program well, you should already be familiar with the basic shape, and anatomical features of the mandible, and you should know the meaning of certain anatomical descriptive terms such as fossa, ridge and foramen.
Dental and Periodontal Anatomy
First of all, several structures of the tooth and periodontium must be clearly identifiable in any periapical radiograph. These structures, labeled in the drawing, include the enamel, dentin, pulp, periodontal membrane and alveolar bone. In a periapical radiograph, the enamel, which is the hardest substance in the human body, appears as the most radiopaque (lightest) part of the crown of the tooth. The dentin is a less-mineralized hard structure of the tooth between the enamel and the pulp and is not as radiopaque as the enamel. The pulp is the radiolucent (dark) area in the center of the root and crown where the soft tissues, which include the nerves and blood supply, are located. The periodontal membrane appears in a periapical radiograph as a space, or dark radiolucent line, adjacent to the tooth root. Next to the periodontal ligament space there is a thin light or radiopaque line called the lamina dura ,which is the radiographic representation of the outer cortex of the alveolar bone. Finally, the radiograph also shows the alveolar bone, the supportive housing for all of the dentition.

As you progress through this program, you ll see many different radiographs which all show normal features. You ll note that even normal features don t have the same appearance or distinctiveness in every patient. You ll also see many features that are not labeled or discussed specifically. Examine each radiograph carefully. Try to identify each feature, and compare different views of similar features. Remember that you re using this program to teach yourself, so start now to develop your interpretive and analytical skills.

The mandible forms the skeleton of the lower jaw and houses the lower dentition. Since the mandible is an articulated bone, it is movable, and thereby capable of providing necessary movements for the mastication of food and the production of speech. To facilitate this movement the mandible has several areas of attachment for the muscles participating in mastication and speech. These bony prominences for muscle attachments are often referred to as ridges and tubercles. This drawing demonstrates where some of these muscles are located. More will be said about these areas later in the program.

The lower border of the mandible is the thick cortical plate that forms the lower edge of the mandible. The solid thickness of bone along the inferior border of the mandible is seen in the radiograph as a uniform wide radiopaque band at the margin of the mandible.

The mental ridges are elevated ridges of bone located along the anterior aspect of the mandible. The ridges are also known as the mental tubercles and fuse at the midline to form the mental protuberance, the anteriormost aspect of the mandible. This periapical radiograph demonstrates the radiopaque margin of the mental ridges. Study these and compare the varying appearance of these landmarks.

The genial tubercles are small bony spines found on the lingual aspect of the mandible adjacent to the midline at the attachment of the geniohyoid and genioglossus muscles. In this close-up view you can clearly see the genial tubercles on the lingual midline. Notice also the small opening right in the middle of the tubercles. This is called the lingual foramen, an opening in the lingual midline of the mandible for a small vessel. This illustration demonstrates the function of the genial tubercles, or mental spines as they are sometimes called, as a locus for the attachment of the geniohyoid and genioglossus muscles. This occlusal radiograph of an edentulous mandible depicts the genial tubercles as seen in an axial plane. If you look closely here you can also discern the attached muscles, which make up the floor of the mouth. In this periapical radiograph of the mandibular anterior region, the genial tubercles appear as a distinct circular radiopacity, an area of dense bone, near the midline below the apices of the teeth. The lingual foramen appears as a small circular radiolucent area surrounded by the genial tubercles.

The soft tissues of the superior margin of the lower lip will often be projected onto the anterior periapical radiograph and are seen as a horizontal step or change in the general radiopacity of crowns of the teeth. The darker side of the step is toward the incisal edge of the crowns and represents the air space above the lip. Sometimes this lip line is projected lower and will be superimposed over the free gingival margin or the crest of the alveolar ridge. In some individuals, a particularly prominent lower lip may produce a second horizontal line which delineates the rolled portion of the lip from the thinner soft tissues of the face between the lip and above the chin. The lower arrows in this image denoted the inferior margin of the lower lip. Note that the soft tissues of the face immediately below the inferior margin of the lip are not as thick and appear slightly more radiolucent. The top most arrows in this image point to the superior margin of the lip.

Another soft tissue shadow that occasionally appears on mandibular anterior periapical films is the margin of the soft tissue of the chin. This feature tends to appear on radiographs of individuals who have prominent chins and in those situations where the central ray parallels the upper "shelf" of the chin. The difference in thickness of soft tissues of the chin shelf and those just below the lip are sufficient to cause an abrupt change in density or a "density step" on the image. The chin soft tissue margin, delineated by the white arrows, should not be confused with the mental ridges, demonstrated by the black arrows, which appear as radiopaque bands below the soft tissue border of the chin.

In the mandible, as in the cranium shown here, nutrient canals, which hold blood vessels, run along the inner surface of the bone cortex, where they lie in slight depressions. These are visible radiographically because the bone is proportionately thinner where it is displaced by a vessel and thus appears more radiolucent.
Radiographically, nutrient canals appear as uniform thin radiolucent lines. The margin of these lines is often slightly more radiopaque than the adjacent bone. Sometimes these canals can be seen running toward the apices of teeth as accessory branches of the inferior alveolar canal. In this instance the canals contain both blood vessel and nerve supplies to the tooth and are termed accessory canals. Nutrient canals are most noticeable when they appear between roots or within edentulous areas where they lie against the bony wall and reduce the thickness of bone in the area of the vessel.

Another anatomical feature you will encounter occasionally is shown in this clinical intraoral image. The rounded protuberances on the lingual surfaces of the alveolar process are called mandibular tori, or singularly, a mandibular torus. This fairly common feature is a hard, bony enlargement of the alveolar cortex. Radiographically, mandibular tori appear as large rounded radiopacities in the area of the roots of the teeth, usually the canines and premolars. The tori are quite distinct in these two anterior periapical projections.

The mental foramen is an opening in the facial aspect of the mandible in the premolar area. This photograph of the mandible demonstrates the usual location of the mental foramen. You can see that its position will cause it to appear radiographically near the apex of the lower second premolar. As this drawing demonstrates,the mental foramen provides the exit point from within the mandible for the mental nerve, as well as the inferior alveolar artery. In periapical radiographs the mental foramen appears as a rounded radiolucency in the apical region distal to the canine and mesial to the first molar. Often it is not as distinct as some other landmarks, but recognizing it is important. Sometimes the mental foramen will be superimposed on the apex of a premolar, and will give the appearance of pulpal pathology. The best way to differentiate periapical disease from the mental foramen is to identify the periodontal membrane space to see if it is confluent with the radiolucent opening. If the apical radiolucency is due to periapical pathology, the periodontal membrane will appear to join the radiolucency, but if the lucent area is due to the mental foramen, then the periodontal membrane space will remain intact, and can be distinctly followed around the tooth apex. Notice the difference in appearance of the pathology at the apex of the distal root of the first molar and the radiolucency of the mental foramen which superimposes on the apex of the second premolar.

In discussing the next feature it is important to remember the arrangement of the blood and nerve supply to the mandible. As you can see from this drawing, the trigeminal nerve and the maxillary artery supply the mandible and give rise to the inferior alveolar nerve and the inferior alveolar artery respectively. The inferior alveolar nerve and artery pass through the mandible through a structure called the mandibular canal. The mandibular canal extends from the mandibular foramen, on the lingual aspect of the ramus, through the body of the mandible under the roots of the molar teeth. The canal terminates at the mental foramen, where the mental nerve branches buccally through the cortex to innervate the soft tissues of the lower lip and chin area. The rest of the inferior alveolar nerve extends mesially to innervate the canines and incisors. This anterior extension of the inferior alveolar canal is called the anterior loop. In this premolar radiograph, the mandibular canal is delineated by black arrows, the mental foramen by a white circle, and the anterior loop by white arrows. In this posterior lingual view of the mandible, you can clearly see the mandibular foramen, which is the proximal or posterior opening of the mandibular canal. This view illustrates the route followed by the mandibular canal from the lingual posterior to the facial anterior at the mental foramen. The mandibular canal appears radiographically as two roughly parallel radiopaque lines traversing the body of the mandible. In this radiograph you can see the mandibular canal clearly below the apicies of the molar teeth. Look closely to distinguish the radiolucent mental foramen, at the anterior extent of the canal.
You ll frequently see the mandibular canal in periapical radiographs of the body of the posterior mandible. The tube-like nature of this structure gives it the characteristic radiographic appearance seen here. The radiographic appearance of the mandibular canal is due to the fact that the X-ray beam passes through the denser cortices of the outer edges of the canal to produce radiopaque lines, while the center, without so much superimposition of bone, retains a radiolucent characteristic.

The internal oblique ridge (or mylohyoid line) is an eminence of bone extending along the lingual aspect of the mandible. It serves as the attachment point for the chief muscle of the mouth floor, the mylohyoid muscle.
This drawing shows the location and direction of the mylohyoid muscle, which is attached to the mandible at the internal oblique ridges.
Radiographically the internal oblique ridge appears as a radiopaque band extending from the terminal molar region to the premolar area, as seen in this periapical projection. Note that part of the mandibular canal is visible just below the mylohyoid line and is often superimposed on the image of the internal oblique ridge.

Directly below the internal oblique ridge is a depression in the lingual aspect of the mandible called the submandibular fossa. This concavity is visible radiographically since the thickness of bone is substantially reduced in this area. The submandibular fossa is the location of the submandibular salivary gland, as you can see from this drawing. The radiolucent appearance of the submandibular fossa is well demonstrated in this periapical molar view. It is important to recognize this as normal anatomy because this is another feature which may resemble pathology such as tumors or cysts. When a steep upward projection geometry is used to produce the periapical image, the shape of the internal oblique ridge produces a distinct opaque band that delineates the superior border of the submandibular fossa. When a flatter vertical projection geometry is used the submandibular fossa appears as a dark area with indistinct borders as seen in this image.

The external oblique ridge is a ridge of bone located along the facial aspect of the mandible, which extends from the superior aspect of the posterior body of the mandible down to the necks of the molar teeth. It runs in the same direction as the internal oblique ridge, but is located on the facial, or external surface of the mandible. The external oblique ridge serves as the attachment point for the buccinator muscle, as demonstrated in this drawing. The next two periapical projections demonstrate the radiographic appearance of the external oblique ridge. To distinguish radiographically between the internal and external oblique ridges, note that the external ridge is always superior to the internal oblique ridge. In this image the external oblique ridge is denoted by white arrows while the internal oblique ridge is demarcated by black arrows.
This concludes the textual material on normal radiographic anatomy of mandibular periapical projections. You can review this material using the list of Mandibular features in the frame on the left if you wish. When you are ready, take the short review quiz to help you make sure that you ve mastered the material that has been presented.
This quiz will help you review the anatomic features presented in this program. It should be easy for you but if not, use it as a guide to what you should study further. You ll be shown a number of radiographs and asked to key in the names of the delineated features.
Maxillary Anatomy
This unit continues with an introductory identification of the normal anatomy seen in maxillary periapical radiographs. When you complete this portion of the program, you should be able to name the normal anatomic structures shown in a maxillary periapical radiograph and to point out any normal structure in the image. In all there are 26 structures you ll learn to recognize and identify. When you have completed this material, a quiz is offered to help you review and make sure you ve reached these objectives.
The nasal fossa, sometimes called the nasal antrum, is in the air passage just behind the soft tissues of the nose. In this front view of a skull you can see clearly the open space in the area of the nose, which is the nasal fossa. Actually, there are two spaces, or fossae, one on either side of a thin septum at the midline. This is a periapical projection of the central incisor region. The two radiolucent areas delineated in red are the nasal fossae. The shapes of the fossae are determined in part by adjacent structures including the nasal septum and the inferior conch.
The nasal septum is the thin wall of bone in the midline of the face that separates the right and left nasal fossae. This skull photograph shows the nasal septum as well as the bony floor of the nasal fossae. In this periapical projection of the central incisor region, the nasal septum extends vertically at the top, between the right and left nasal cavities. Identify these features, and locate the radiopaque lines marking the floor or inferior border of the nasal fossae.
The anterior nasal spine is the triangular protuberance of bone that extends forward from the inferior aspect of the nasal cavity at the midline. This image demonstrates the diamond shaped radiopacity of the anterior nasal spine. This bony feature serves as an attachment point for the nasal cartilage.
The mid-palatine suture is the line down the center of the maxilla where embryonic palatal shelves joined at the midline to form the hard palate. That line is apparent on this skull. In this frontal view of a skull, you can see the mid-palatine suture as it extends anteriorly between the two halves of the maxilla. Also you are looking straight-on at the anterior nasal spine. This is the perspective of most central incisor projections. The mid-palatine suture appears in this central incisor periapical projection as a dark, or radiolucent, line at the midline (white arrows). You can also see the more radiopaque inverted triangle at the top of the image that represents the anterior nasal spine.
Several structures of the tooth and periodontium should be clearly identifiable in any periapical radiograph. These structures, labeled in this drawing, include the enamel, dentin, pulp, periodontal membrane, and alveolar bone.
In a periapical radiograph, the enamel appears as the most radiopaque part of the crown of the tooth. The dentin, a less mineralized area of the tooth between the enamel and the pulp is not as radiopaque. The pulp is the radiolucent area in the center of the root and crown where the soft tissues which include the nerve and blood supply are located. Study this radiograph to identify precisely the location and extent of these features.
The periodontal membrane appears in a periapical radiograph as a space, or radiolucent line adjacent to the tooth root. Next to the periodontal membrane space you can see a thin radiopaque line, called the lamina dura, which is the radiographic representation of the outer cortex of the alveolar bone surrounding the tooth root. Finally, the radiograph also shows the alveolar bone, the bony housing for all the dentition.
The incisive foramen is the opening in the midline of the palate just posterior to the central incisors. Here an anterior occlusal view of a skull demonstrates the incisive foramen. This view also shows the posterior extent of the nasal septum.
This drawing illustrates how the incisive foramen gives passage to the nasopalatine artery and nerve which course through the incisive canal and foramen to innervate the anterior palatal soft tissues.
In the central incisor periapical projection shown here, the white arrows indicate the appearance of the incisive canal while the black arrows indicate the incisive foramen.
Several soft tissue shadows often appear in the maxillary anterior region. The border of the nose produces a well-defined density difference step. The delineation of the border of the nose produces a symmetrical bow-like shape on the central incisor periapical image. The alar cartilage of the nose is seen as a rounded soft tissue radiopacity in the canine lateral projection.
The border of the lip will occasionally project across the crowns of the teeth as a linear density step. If the lip line is projected across the contact area of a crown, the radiolucent / radiopaque step may simulate a carious lesion.
Another common soft tissue shadow is the nasolabial fold. This fold marks the anterior border of the thicker soft tissues of the cheek including the buccal fat pad. The fold produces a linear step density that courses from the region above the apicies of the canine or lateral incisor to the occlusal plane in the premolar region.
The maxillary sinuses are pyramid-shaped cavities in the mid-facial aspect of the skull. As the frontal view drawing shows, the maxillary sinuses are bilateral structures, located beside each nasal fossa. You can see from the side view how the sinus extends posteriorly near the roots of the maxillary teeth. Parts of the maxillary sinus may appear in many of the maxillary periapical projections.
In this periapical view of the canine region, the anterior wall of the maxillary sinus is identified by the white arrows.
Another view of the canine region demonstrates an important landmark: the antral Y or inverted Y formation. This landmark is formed by the intersection of the floor of the nasal cavity and the anterior wall of the maxillary sinus. Because the inverted Y represents the superimposition of two features projected radiographically over each other the formation may appear different in different projections.
The next two features of normal anatomy are the incisive fossa and the canine fossa. These are indentations in the maxillary alveolar process, shown in shadow in this skull view, which may result in a radiolucent region on the film. The incisive fossa is the indentation between the roots of the central and lateral incisors, and the canine fossa is between the roots of the lateral incisor and canine.
The incisive fossa is demonstrated radiographically in the incisor projection shown on the left here (white arrows). Note how this radiolucency is set off by the radiopaque boundaries of the central incisor, lateral incisor, and border of the nose (black arrows). The same type of defined radiolucency may be produced by the canine fossa as is evident in this lateral-canine projection. These fossae appear radiographically as teardrop-shaped areas of less radiopaque alveolar bone, located between and a little above the roots of the incisors (incisive fossa), or between the roots of the lateral incisor and canine (canine fossa).
The maxillary sinus, which you ve already identified in some anterior projections, is also a common feature in several posterior maxillary periapical projections. The sinuses are radiolucent, air-filled cavities which occupy a large portion of the maxilla above the posterior teeth on each side. Notice in this front view how close the maxillary sinus typically comes to the molar roots. In this cutaway side view of the maxilla, you get a clearer idea of where the sinus is located relative to the posterior teeth. Study this view and imagine how the maxillary sinus, and particularly its lower border, will appear in periapical radiographs. The dotted line shows where a periapical film packet might be placed. This lateral cephalometric radiograph demonstrates the location and appearance of the entire maxillary sinus.
This periapical view of the maxillary molar region demonstrates the maxillary sinus and its inferior border. The inferior border or "floor"of the maxillary sinus appears as a radiopaque line representing the denser bony cortex of the margin of the sinus.
Sometimes, the maxillary sinus will fill an extraction site and present the radiographic appearance you see here. This extension of the air-filled sinus beyond its typical boundaries is called pneumatization.
The tendency for the maxillary sinus to pneumatize and form multiple lobes may give rise to the appearance of radiopaque lines extending from the floor of the sinus into the radiolucent interior. These white lines represent cortical extensions of the wall of the sinus and represent the wall of a smaller compartment within the sinus. Because these walls subdivide the sinus they are termed sinus septa or septum (singular). Although this anatomic feature looks somewhat like the inverted Y formation, you can distinguish the two by their locations. The inverted Y would rarely appear this far posterior in periapical projections.
The malar process is the portion of the maxilla that protrudes to meet the zygomatic bone, or cheekbone. The area of this junction, or suture, is shown well in this skull view; however, the suture is rarely seen in periapical views.
In this view from below you can see even more clearly how the zygomatic arch stands out from the skull, and how the malar process extends to join the arch. The pencil is pointing to the suture between the maxilla and zygomatic bones. This view approximates the perspective of the periapical radiograph. You can see how the malar process, where the zygomatic bone attaches to the maxilla, would show up radiographically as the characteristic curved radiopaque shape. In this periapical view of the malar process you can also see a portion of the zygomatic bone extending toward the posterior. The margin of the broad radiopaque area delineated by black arrows, represents the zygomatic bone (cheekbone) which is connected with the U shaped malar process (delineated by white arrows).
You should recognize the maxillary tuberosity as it appears radiographically. The maxillary tuberosity is the rounded bony eminence just posterior to the most distal molar, at the distal end of the maxillary alveolar ridge. This photograph shows both tuberosities well. This inferior view shows the area of the tuberosities, as indicated by the pencil. It is a little difficult to see the rounded shape of the maxillary tuberosity from this view. This periapical radiographic projection of the maxillary second molar region clearly demonstrates the maxillary tuberosity area.
Often the posterior border of the maxillary sinus will pneumatize or extend, into the tuberosity area, as seen in this radiograph. The white arrows indicate the oral boundary of the tuberosity. The black arrows indicate the floor of the sinus that has pneumatized into the area where a third molar has been extracted.
The lateral pterygoid plate, pointed out in this frame, is a thin, bony extension of the sphenoid bone, to which are attached the lateral pterygoid muscle as well as muscles of the throat.
The hamulus, shown here, is a small bony spine extending downward below the lateral pterygoid plate. Note that both of these features are part of the sphenoid bone, and lie posterior to the maxillary tuberosity. The radiographic appearance of these features is occasionally visible in periapical views of the posterior area. The hamulus is delineated with white arrows in this image.
Take a moment to identify anatomical features visible in this palatal view of a skull. This view shows well the zygomatic bones or cheekbones, and the malar processes of the maxilla. Just posterior to the last molars are the rounded maxillary tuberosities. You can see the thin, wing-shaped lateral pterygoid plates, especially the one on the right side, that stands out against shadow. Incidentally, our word "pterygoid" comes from the Greek word meaning "wing-shaped." In this molar periapical view the lateral pterygoid plate is visible just posterior to the tuberosity.
Lining the walls of the maxillary sinus are numerous blood vessels which are ultimately branches of the internal maxillary artery. Notice the size and location of these vessels in the wall of the maxillary sinus, shown in this drawing. Sometimes blood vessels running along a bony surface lie in slight depressions in the bone, as you can see in this view of the interior of the cranium. The vessels in the wall of the maxillary sinus lie in similar depressions, and it is these that are visible radiographically, since the bone is slightly thinner and thus more radiolucent, there. Radiographically, you can see the location of vascular channels in the wall of the maxillary sinus as a radiolucent line, indicated in this periapical projection of the molar region.
Another landmark you should know is the posterior floor of the nasal fossa or hard palate. In this lateral cephalometric radiograph, you can distinguish the two parallel radiopaque lines which represent these features. The hard palate, indicated by the black arrows is the roof of the oral cavity. The floor of the nasal fossa, indicated by the white arrows, is immediately above the palate. Sometimes only a single line is apparent, depending on the angulation of the projection. Notice that due to the vault of the palate, the hard palate and posterior floor of the nasal fossa usually appear radiographically above the floor of the maxillary sinus.
The posterior floor of the nasal fossa, or hard palate, can also be seen in this posterior periapical projection, as the thin radiopaque line extending horizontally along the top of the image. The nasal fossa is projected above the floor of the maxillary sinus, which you see near the apices of the teeth here. You should also note in this radiograph the sinus septum and the J-shaped malar process.
A common variation in the roof of the palate that may be seen in as many as 20% of patients is the presence of a bony swelling along the midline of the middle palate. This excess bone is called a torus palatinus. A torus may consist of several lobes of dense bone as noted by the white arrows here. The radiopaque zygoma is outlined with black arrows and extends off the distal portion of this image. A torus may also appear in anterior maxillary views as denoted by the black arrows in this image. White arrows denote the alar cartilage of the nose in this image. Note how much less radiopaque the soft tissues of the nose are in relation to the dense bone of the torus palatinus.
Another cartilaginous radiopacity that may appear on anterior maxillary radiographs is the inferior conch or inferior nasal turbinate. There are actually three turbinates on each side of the nasal antrum; however, only the most inferior of these is routinely projected onto the periapical view of the incisor region. Notice how the conch appearance, which is outlined by white arrows, is similar to the previous image of the torus. Principle differences are that the conch is not as highly calcified as the torus and appears only slightly more radiopaque than the alar cartilage of the nose. Also the conch lies within the more radiolucent nasal fossa and is circumscribed by the border of the fossa and the nasal septum whereas the torus palatinus crosses the nasal midline and may appear to extend below the floor of the nasal fossa.
The last anatomical landmark to be presented in this program is the coronoid process of the mandible. This is the thin triangular prominence off the upper part of the mandible. You can see from this perspective how the tip of the coronoid process may appear in some maxillary molar projections. The coronoid process of the mandible serves as an attachment for certain muscles of mastication, as you can see in this drawing. The black arrows depict the tip of the coronoid process in this periapical radiograph of the molar region. The white arrows in this image depict the margin of rounded homogenous radiopacity arising from the floor of the maxillary sinus. This morphologic pattern and radiopacity is characteristic of an assymptomatic pathologic condition called mucous retention cyst of the maxillary sinus. In the absence of sinus symptoms this condition only requires recognition and no further treatment. The tip of the coronoid process is also a homogenous radiopacity that may project on the posterior sinus region. Because the mouth is partially opened to accommodate the image receptor holder, the coronoid process rotates forward and downward. The resulting position allows the tip of the coronoid to be projected onto the tuberosity of the maxilla. Occasionally this geometry produces an image where the conical form of the coronoid resembles a third molar root.


المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .