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Encyclopedia > Ramus of the mandible
Bone: Ramus mandibulae
Figure 1: Mandible. Outer surface. Side view
Figure 2: Mandible. Inner surface. Side view
Gray's subject #44 173

('ramus mandibulæ; perpendicular portion') The ramus of the mandible is quadrilateral in shape, and has two surfaces, four borders, and two processes. File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... It has been suggested that this article or section be merged with jaw. ... File links The following pages link to this file: Mandible Wikipedia:Grays Anatomy images with missing articles 4 Categories: Public domain images ... It has been suggested that this article or section be merged with jaw. ... In geometry, a quadrilateral is a polygon with four sides and four vertices. ... In geometry, two sets have the same shape if one can be transformed to another by a combination of translations, rotations and uniform scalings. ...

Contents

Surfaces

The lateral surface [Fig. 1] is flat and marked by oblique ridges at its lower part; it gives attachment throughout nearly the whole of its extent to the masseter. In human anatomy, the masseter is one of the muscles of mastication. ...


The medial surface [Fig. 2] presents about its center the oblique mandibular foramen, for the entrance of the inferior alveolar vessels and nerve. The Mandibular Foramen is an opening on the internal surface of the ramus for the mandibular vessels and nerve to pass. ... The inferior alveolar nerve is a branch of the mandibular nerve, which is itself the third branch (V3) of the fifth cranial nerve, the trigeminal nerve (cranial nerve V). ...


The margin of this opening is irregular; it presents in front a prominent ridge, surmounted by a sharp spine, the lingula mandibulae, which gives attachment to the sphenomandibular ligament; at its lower and back part is a notch from which the mylohyoid groove runs obliquely downward and forward, and lodges the mylohyoid vessels and nerve.


Behind this groove is a rough surface, for the insertion of the internal pterygoid muscle (Pterygoideus internus). The mandibular canal runs obliquely downward and forward in the ramus, and then horizontally forward in the body, where it is placed under the alveoli and communicates with them by small openings. The mandibular canal runs obliquely downward and forward in the ramus, and then horizontally forward in the body, where it is placed under the alveoli and communicates with them by small openings. ...


On arriving at the incisor teeth, it turns back to communicate with the mental foramen, giving off two small canals which run to the cavities containing the incisor teeth. The mental foramen is a foramen in the mandible. ...


In the posterior two-thirds of the bone the canal is situated nearer the internal surface of the mandible; and in the anterior third, nearer its external surface.


It contains the inferior alveolar vessels and nerve, from which branches are distributed to the teeth.


Borders

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, which may be either inverted or everted 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 anterior border is thin above, thicker below, and continuous with the oblique line. The medial pterygoid, or Pterygoideus internus (Internal pterygoid muscle), is a muscle of mastication with two heads. ... The stylomandibular ligament is a specialized band of the cervical fascia, which extends from near the apex of the styloid process of the temporal bone to the angle and posterior border of the ramus of the mandible, between the Masseter and Pterygoideus internus. ...


The posterior border is thick, smooth, rounded, and covered by the parotid gland. 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. The parotid gland is the largest of the salivary glands. ...


Processes

Coronoid Process

The Temporalis; the zygomatic arch and Masseter have been removed. (Coronoid process labeled at center bottom.)
The Temporalis; the zygomatic arch and Masseter have been removed. (Coronoid process labeled at center bottom.)

The Coronoid Process (processus coronoideus) is a thin, triangular eminence, which is flattened from side to side and varies in shape and size. Image File history File links Gray382. ... Image File history File links Gray382. ...


Its anterior border is convex and is continuous below with the anterior border of the ramus; its posterior border is concave and forms the anterior boundary of the mandibular notch. Its lateral surface is smooth, and affords insertion to the Temporalis and Masseter. The temporalis muscle is one of the muscles of mastication. ... In human anatomy, the masseter is one of the muscles of mastication. ...


Its medial surface gives insertion to the Temporalis, and presents a ridge which begins near the apex of the process and runs downward and forward to the inner side of the last molar tooth.


Between this ridge and the anterior border is a grooved triangular area, the upper part of which gives attachment to the Temporalis, the lower part to some fibers of the Buccinator. Buccinator The buccinator is a muscle of which the bulk of is located in the cheeks. ...


Condyloid Process

The Condyloid Process (processus condyloideus) is thicker than the coronoid, and consists of two portions: the condyle, and the constricted portion which supports it, the neck.


The condyle presents an articular surface for articulation with the articular disk of the temporomandibular joint; it is convex from before backward and from side to side, and extends farther on the posterior than on the anterior surface. The temporomandibular joint (TMJ) is a diarthrosis joint that connects the mandible (lower jaw) to the temporal bone at the side of a skull. ...


Its long axis is directed medialward and slightly backward, and if prolonged to the middle line will meet that of the opposite condyle near the anterior margin of the foramen magnum.


At the lateral extremity of the condyle is a small tubercle for the attachment of the temporomandibular ligament. The temporomandibular ligament (external lateral ligament) consists of two short, narrow fasciculi, one in front of the other, attached, above, to the lateral surface of the zygomatic arch and to the tubercle on its lower border; below, to the lateral surface and posterior border of the neck of the mandible. ...


The neck is flattened from before backward, and strengthened by ridges which descend from the forepart and sides of the condyle.


Its posterior surface is convex; its anterior presents a depression for the attachment of the Pterygoideus externus. The lateral pterygoid (or external pterygoid) is a muscle of mastication with two heads. ...


The mandibular notch, separating the two processes, is a deep semilunar depression, and is crossed by the masseteric vessels and nerve.


This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant. The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ... An illustration from the 1918 edition Henry Grays Anatomy of the Human Body, commonly known as Grays Anatomy, is an anatomy textbook widely regarded as a classic work on human anatomy. ...

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Facial bones

maxilla: body of maxilla: Incisive fossa | Maxillary sinus | Canine fossa | Infraorbital foramen | Anterior nasal spine | Alveolar canals | Infraorbital canal | Pterygopalatine canal
Zygomatic process | Frontal process (Agger nasi | Anterior lacrimal crest) | Alveolar process | Palatine process (Incisive foramen | Incisive canals | Foramina of Scarpa | Premaxilla | Anterior nasal spine) The maxillae are the largest bones of the face, except for the mandible, and form, by their union, the whole of the upper jaw. ... On the anterior surface of the maxilla, just above the eminences corresponding to the incisor teeth is a depression, the incisive fossa, which gives origin to the Depressor alæ nasi; to the alveolar border below the fossa is attached a slip of the Orbicularis oris; above and a little lateral... The maxillary sinus is the largest paranasal sinus. ... Lateral to the incisive fossa is another depression, the canine fossa; it is larger and deeper than the incisive fossa, and is separated from it by a vertical ridge, the canine eminence, corresponding to the socket of the canine tooth; the canine fossa gives origin to the Caninus. ... Above the canine fossa is the infraorbital foramen, the end of the infraorbital canal; it transmits the infraorbital vessels and nerve. ... Medially, the anterior surface of the maxilla is limited by a deep concavity, the nasal notch, the margin of which gives attachment to the Dilatator naris posterior and ends below in a pointed process, which with its fellow of the opposite side forms the anterior nasal spine. ... The infratemporal surface of the maxilla is pierced about its center by the apertures of the alveolar canals, which transmit the posterior superior alveolar vessels and nerves. ... One of the canals of the orbital surface of the maxilla, the infraorbital canal, opens just below the margin of the orbit. ... On the posterior part of the maxillary surface of the palatine bone is a deep vertical groove, converted into the pterygopalatine canal, by articulation with the maxilla; this canal transmits the descending palatine vessels, and the anterior palatine nerve. ... The zygomatic process of the maxilla (malar process) is a rough triangular eminence, situated at the angle of separation of the anterior, zygomatic, and orbital surfaces. ... The agger nasi is a small ridge on the lateral side of the nasal cavity. ... The lateral margin of the lacrimal fossa is named the anterior lacrimal crest, and is continuous below with the orbital margin; at its junction with the orbital surface is a small tubercle, the lacrimal tubercle, which serves as a guide to the position of the lacrimal sac. ... When the two maxillæ are articulated, a funnel-shaped opening, the incisive foramen, is seen in the middle line, immediately behind the incisor teeth. ... In the opening of the incisive foramen, the orifices of two lateral canals are visible; they are named the incisive canals or foramina of Stenson; through each of them passes the terminal branch of the descending palatine artery and the nasopalatine nerve. ... In the maxilla, occasionally two additional canals are present in the middle line of the palatine process; they are termed the foramina of Scarpa, and when present transmit the nasopalatine nerves, the left passing through the anterior, and the right through the posterior canal. ... The premaxilla is a pair of small bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. ... Medially, the anterior surface of the maxilla is limited by a deep concavity, the nasal notch, the margin of which gives attachment to the Dilatator naris posterior and ends below in a pointed process, which with its fellow of the opposite side forms the anterior nasal spine. ...


lacrimal bone: Posterior lacrimal crest | Lacrimal groove The lacrimal bone (Os Lacrimale), the smallest and most fragile bone of the face, is situated at the front part of the medial wall of the orbit . ... The lateral or orbital surface of the lacrimal bone is divided by a vertical ridge, the posterior lacrimal crest, into two parts. ...


zygomatic bone: Zygomaticofacial foramen | Zygomaticotemporal foramen | Zygomaticoörbital foramina The zygomatic bone (also known as the zygoma; Os Zygomaticum; Malar Bone) is a paired bone of the human skull. ... The malar surface of the zygomatic bone is convex and perforated near its center by a small aperture, the zygomaticofacial foramen, for the passage of the zygomaticofacial nerve and vessels; below this foramen is a slight elevation, which gives origin to the Zygomaticus. ... Near the center of the temporal surface of the zygomatic bone is the zygomaticotemporal foramen for the transmission of the zygomaticotemporal nerve. ... On the orbital process of the zygomatic bone are seen the orifices of two canals, the zygomaticoörbital foramina; one of these canals opens into the temporal fossa, the other on the malar surface of the bone; the former transmits the zygomaticotemporal, the latter the zygomaticofacial nerve. ...


palatine bone: Pterygopalatine fossa | Pterygoid fossa | Horizontal plate (Posterior nasal spine) | Perpendicular plate (Pterygopalatine canal | Sphenopalatine foramen | Pyramidal process)
processes (Orbital | Sphenoidal) The palatine bone is a bone situated at the back part of the nasal cavity between the maxilla and the pterygoid process of the sphenoid. ... In the skull, the pterygopalatine fossa is the space between the lateral pterygoid plate (which is part of the sphenoid bone), and the palate. ... The Pterygoid fossa, or the sphenoid bone is wedged between several other bones in the front of the cranium. ... The horizontal part of the palatine bone (horizontal plate) is quadrilateral, and has two surfaces and four borders. ... Its medial end of the posterior border of the horizontal plate of palatine bone is sharp and pointed, and, when united with that of the opposite bone, forms a projecting process, the posterior nasal spine for the attachment of the Musculus uvulæ. See also anterior nasal spine This article was... The vertical part (perpendicular plate) of the palatine bone is thin, of an oblong form, and presents two surfaces and four borders. ... On the posterior part of the maxillary surface of the palatine bone is a deep vertical groove, converted into the pterygopalatine canal, by articulation with the maxilla; this canal transmits the descending palatine vessels, and the anterior palatine nerve. ... The processes of the superior border of the palatine bone are separated by the sphenopalatine notch, which is converted into the sphenopalatine foramen by the under surface of the body of the sphenoid. ... The pyramidal process of the palatine bone projects backward and lateralward from the junction of the horizontal and vertical parts, and is received into the angular interval between the lower extremities of the pterygoid plates. ... The orbital process of the palatine bone is placed on a higher level than the sphenoidal, and is directed upward and lateralward from the front of the vertical part, to which it is connected by a constricted neck. ... The sphenoidal process is a thin, compressed plate, much smaller than the orbital, and directed upward and medialward. ...


mandible: body (Symphysis menti, Mental foramen, Mylohyoid line) | Ramus mandibulae (Mandibular foramen, Mandibular canal, Mandibular notch) It has been suggested that this article or section be merged with jaw. ... The external surface of the mandible is marked in the median line by a faint ridge, indicating the Symphysis menti or line of junction of the two pieces of which the bone is composed at an early period of life. ... The mental foramen is a foramen in the mandible. ... Extending upward and backward on either side from the lower part of the symphysis of the Mandible is the mylohyoid line, which gives origin to the Mylohyoideus; the posterior part of this line, near the alveolar margin, gives attachment to a small part of the Constrictor pharyngis superior, and to... The Mandibular Foramen is an opening on the internal surface of the ramus for the mandibular vessels and nerve to pass. ... The mandibular canal runs obliquely downward and forward in the ramus, and then horizontally forward in the body, where it is placed under the alveoli and communicates with them by small openings. ...


others: nasal bone | inferior nasal conchae (maxillary process) | vomer The Nasal Bones (Ossa Faciei & Ossa Nasalia) are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, the bridge of the nose. ... It has been suggested that this article or section be merged with Nasal concha. ... The vomer bone is one of the unpaired facial bones of the skull. ...


 
 

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