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59-515: One of the most interesting aspects of this town is the discovery of an early Mesoamerican skeleton commonly referred to as " Tepexpan man ". Recent research tries to show that the skeleton was not that of a man but that of a woman. The woman was apparently trampled by a raging mastodon around 11,000 BCE. The proposition that Tepexpan Man was a woman has been advanced by one Mexican archaeologist based on DNA analysis. His peers at INAH have not accepted his conclusions and he has not submitted his analysis in

118-572: A feeding tube is utilized, and sometimes a tracheotomy is also performed to maintain respiration in case of swollen muscles. In a technique illustrated in the 19th century, the flesh of the face is incised along the inferior of the mandible and peeled upward for the bone's removal. Complications can involve difficulties with free flap transfer and airway management. Additional side effects include pain, infection, numbness, and (rarely, fatal) bleeding. Even successful surgeries can result in deformity , with an extreme version being referred to as

177-456: A "sharply prominent chin" which would separate him from earlier Neanderthals. Tepexpan Man only had three teeth left in his upper jaw. In his lower jaw, all of the molars had disappeared before his death. This was evidenced by the alveolar sockets being healed and smoothed over in the mandible . What was left on the mandible included incisors, "eye-teeth," and premolars that were worn, but still in decent condition. Dr. Gonzalez also reconstructed

236-455: A 'twin fracture' on the opposite side. There is no universally accepted treatment protocol, as there is no consensus on the choice of techniques in a particular anatomical shape of mandibular fracture clinic. A common treatment involves attachment of metal plates to the fracture to assist in healing. The mandible may be dislocated anteriorly (to the front) and inferiorly (downwards) but very rarely posteriorly (backwards). The articular disk of

295-403: A Mexican archaeologist has proposed that Tepexpan 'man' was actually a woman. Tepexpan Man exhibits a healed fracture on his right ulna. De Terra hypothesized that due to his fracture and the proximity to mammoth fossils, Tepexpan Man may have been a hunter who was either killed by his fellow men or mortally wounded while hunting. The Science Newsletter claims that the individual suffered from

354-402: A bone (ossifies) from Meckel's cartilage, which forms the cartilaginous bar of the mandibular arch and, dorsally, parts of the middle ear. The two sides of the jawbone are inferiorly fused at the mandibular symphysis (the chin) during the first year of life. The cartilage of the ramus is replaced by fibrous tissue, which persists to form the sphenomandibular ligament . Between the lingula and

413-525: A condition of shock in humans, e.g. when someone's mouth suddenly hangs agape in response to something. The exaggerated visual gag of a jaw dropping to the floor was a trademark of American animation director Tex Avery , who would often employ it when the Big Bad Wolf spies a sexually attractive woman. Gobstoppers , a type of hard candy, are known in North America as jawbreakers due to

472-473: A deceased person's age. Dental remains of Nazi leader Adolf Hitler , including part of a mandible with teeth, were the solitary physical evidence used to confirm his death in 1945. In the Hebrew Bible and Christian Old Testament Book of Judges , Samson used a donkey's jawbone to kill a thousand Philistines . As early as 1900, the phrase jaw-dropping was used as an adjective to describe

531-401: A faint ridge, the oblique line, which is continuous with the anterior border of the ramus. Attached to this is the masseter muscle ( related to mastication ), the depressor labii inferioris and depressor anguli oris (which support the mouth ), and the platysma (extending down over much of the neck ). From the inside, the mandible appears concave. On either side of the lower symphysis

590-494: A location in the state of Mexico is a stub . You can help Misplaced Pages by expanding it . Tepexpan man The Tepexpan Man is a Pre-Columbian-era skeleton, discovered by archaeologist Helmut de Terra in February 1947, on the shores of the former Lake Texcoco in central Mexico . The skeleton was found near mammoth remains and thought to be at least 10,000 years old. It was fancifully hailed by Time magazine as

649-489: A paper for peer review. Thus, until peer review confirms his work one must leave the matter as conjecture. Additional mammoth fossils from the Late Pleistocene show this site the nearby Santa Isabel Ixtapanto be mammoth kill sites. Mammoths were driven into bogs where they were severely slowed and eventually killed with fluted points as early as 9000 BCE or as late as 7000 BCE. Tepexpan can be considered one of

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708-489: A professor of geoarchaeology at John Moore University in Liverpool, used uranium isotope analysis to date the skeleton. Results showed that Tepexpan Man was 4,700 years old. She argues that contamination of the remains led to the obscured radiocarbon dates. Other critics have claimed that Tepexpan Man was an intrusion in that he was buried at a later date but dug into Pleistocene materials. An analysis of Tepexpan Man that

767-431: A separate ossific center ( splenial center ), is formed in the human mandible by an ingrowth from the main mass of the bone. At birth, the body of the bone is a mere shell, containing the sockets of the two incisor, the canine, and the two deciduous molar teeth , imperfectly partitioned off from one another. The mandibular canal is of large size and runs near the lower border of the bone; the mental foramen opens beneath

826-436: A stiff neck due to the many limy deposits on the cervical vertebrae. This means that Tepexpan Man most likely suffered from arthritis. The Science Newsletter described Tepexpan man in its 1947 edition. It described Tepexpan Man as having "a high-domed, thin-walled skull" which contained "a brain the same size as those of present-day Indians." The writers described a "solidly built" jawline and "prominent" brow ridges, as well as

885-448: Is absorbed so that the mandibular canal becomes nearer the superior border. Sometimes with excessive alveolar process absorption, the mandibular canal disappears entirely and deprives the IAN of its bony protection, although soft tissue continues to guard the nerve. The surgical removal ( resection ) of all or part of the jawbone is known as a mandibulectomy . The removal of a small portion

944-399: Is below the oblique line. The mandibular canal, with the mental foramen opening from it, is closer to the alveolar border. The ramus is oblique in direction, the angle measures about 140°, and the neck of the condyle is more or less bent backward. The posterior of the mandible is notoriously resistant to the full effects of local anesthesia . The IAN provides sensory innervation to much of

1003-460: Is essential for chewing food. Owing to the Neolithic advent of agriculture ( c.  10,000 BCE ), human jaws evolved to be smaller . Although it is the strongest bone of the facial skeleton , the mandible tends to deform in old age; it is also subject to fracturing . Surgery allows for the removal of jawbone fragments (or its entirety) as well as regenerative methods. Additionally,

1062-479: Is irregular; it presents in front a prominent ridge, surmounted by a sharp spine, the lingula of the mandible , 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 medial pterygoid muscle . The mandibular canal runs obliquely downward and forward in

1121-459: Is known as partial mandibulectomy and a larger portion segmental mandibulectomy . This can be performed to remove a tumor, circumvent cancer in nearby areas, and/or in response to infection, osteonecrosis , or injury. The removed portion can be replaced with metal plating or bone from elsewhere in the body. Oral muscles tend to work differently after the procedure, requiring therapy to relearn operations such as eating and speaking. During recovery,

1180-440: Is more pronounced in males but can be visualized and palpated in females. Rarely, a bifid IAN may be present, resulting in a second and more inferiorly placed mandibular foramen. This can be detected by noting a doubled mandibular canal via radiograph. The mandible forms the lower jaw and holds the lower teeth in place. It articulates with the left and right temporal bones at the temporomandibular joints. The condyloid process,

1239-446: Is referred to as the dentary bone or os dentale , and forms the body of the outer surface of the jaw. It is bordered below by a number of splenial bones, while the angle of the jaw is formed by a lower angular bone and a suprangular bone just above it. The inner surface of the jaw is lined by a prearticular bone, while the articular bone forms the articulation with the skull proper. A set of three narrow coronoid bones lie above

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1298-448: Is the mental spine (which can be faint or fused into one), to which the genioglossus (the inferior muscle of the tongue ) attaches; the geniohyoid muscle attaches to the lower mental spine. Above the mental spine, a median foramen and furrow can line the symphysis. Below the mental spine is an oval depression (the digastric fossa of the mandible ) where the digastric muscle attaches. Extending backward and upward on either side from

1357-571: The Andy Gump deformity after the comic book character , whose design apparently lacks a jaw; proposed reconstruction methods include implanting synthetic material , potentially involving 3D printing . Bone loss (as in osteoporosis ) can be mitigated in the jawbone via bone grafting , which is sometimes performed to support dental implants (replacing teeth individually or in groups ). Mandibular prosthetics date back to ancient Egypt and China , but significant advancements were made in

1416-409: The mouth (the upper jaw being known as the maxilla ). The jawbone is the skull 's only movable, posable bone, sharing joints with the cranium's temporal bones . The mandible hosts the lower teeth (their depth delineated by the alveolar process ). Many muscles attach to the bone, which also hosts nerves (some connecting to the teeth) and blood vessels . Amongst other functions, the jawbone

1475-490: The Latin word mandibula 'jawbone' (literally, 'used for chewing'), from mandere 'to chew' and -bula ( instrumental suffix). In addition to mastication, the joint of the jawbone enables actions such speech and yawning , while playing a more subtle role in activities such as kissing and breathing . The mandible of vertebrates evolved from Meckel's cartilage , left and right segments of cartilage which supported

1534-407: The angle measuring from 110° to 120°, also the adult condyle is higher than the coronoid process and the sigmoid notch becomes deeper. The adult mandible is the skull's largest and strongest bone. In old age, the bone can become greatly reduced in volume where there is a loss of teeth, and consequent resorption of the alveolar process and interalveolar septa. Consequently, the chief part of the bone

1593-411: The anterior branchial arch in early fish . Fish jaws surface in species of the large arthrodire genus Dunkleosteus ( fl.  382–358 million years ago ), which crushed prey with their quickly articulating mouths. The lower jaw of cartilaginous fish , such as sharks , is composed of a cartilagenous structure homologous with Meckel's cartilage. This also remains a significant element of

1652-426: The anterior third, nearer its external surface. It contains the inferior alveolar vessels and nerve, from which branches are distributed to the teeth. The mandible has two main holes ( foramina ), found on both its left and right sides: The inferior alveolar nerve (IAN), a branch of the mandibular nerve (itself a major division of the cranium's trigeminal nerve ), enters the mandibular foramen and runs forward in

1711-473: The bone is of great forensic significance. In humans , the mandible is the largest and lowest bone in the facial skeleton . It is the only movable bone of the skull (discounting the vibrating ossicles of the middle ear ). It is connected to the skull's temporal bones by the temporomandibular joints . In addition to simply opening and closing, the jawbone can articulate side to side as well as forward and back. The mandible consists of: The body of

1770-411: The canine tooth the cartilage disappears, while the portion of it below and behind the incisor teeth becomes ossified and incorporated with this part of the mandible. About the sixth week of fetal life, intramembranous ossification takes place in the membrane covering the outer surface of the ventral end of Meckel's cartilage, and each half of the bone is formed from a single center which appears, near

1829-399: The center but raised on both sides to form the mental tubercle . Just above this, on both sides, the mentalis muscles attach to a depression called the incisive foramen . Vertically midway on either side of the body, below the second premolar tooth, is the mental foramen , through which the mental nerve and blood vessels pass. Running backward and upward from each mental tubercle is

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1888-540: The dentary, only few other bones of the lower jaw remain in mammals; the former articular and quadrate bones survive as the malleus and the incus of the middle ear. In recent human evolution , both the oral cavity and jaws have shrunk in correspondence with the Neolithic-era shift from hunter-gatherer lifestyles towards agriculture and settlement, dated to c.  10,000 BCE . This has led to orthodontic malocclusions . The mandible forms as

1947-476: The drainage basin throughout the late Pleistocene and late Holocene. These changes also had large effects on the prehistoric human populations living around the lake at this time. Mandible In jawed vertebrates , the mandible (from the Latin mandibula , 'for chewing'), lower jaw , or jawbone is a bone that makes up the lower – and typically more mobile – component of

2006-436: The environment of Lake Texcoco around the time of Tepexpan Man by analyzing sediments and fossils from the area. Dr. Gonzalez and her team analyzed sand, clay, and volcanic ash, as well as fossils of diatoms (microscopic algae) and ostracods (a form of small crustacean). When Tepexpan Man was alive, the lake was very deep, full of fish, and surrounded by trees. The environment surrounding Lake Texcoco experienced major changes over

2065-506: The fracturing risk they impose on teeth. Owing in part to the forensic evidence of Hitler's death being limited to his dental remains (including a jawbone fragment broken and burnt around the alveolar process), some fringe accounts (bolstered by the Soviet Union , which captured Berlin in 1945) allege that Hitler faked his death (ostensibly along with Eva Braun ). In later decades, American real-estate businessman Fred Trump had

2124-415: The human mandible has four sides, two surfaces, four borders, and two processes. On the outside, the ramus is flat and marked by oblique ridges at its lower part. It gives attachment throughout nearly the whole of its extent to the masseter muscle. On the inside at the center there is an oblique mandibular foramen , for the entrance of the inferior alveolar vessels and nerve . The margin of this opening

2183-482: The jaw in some primitive bony fish, such as sturgeons . In reptiles , Meckel's cartilage ossifies into the (multiple) bones of the lower jaw, while mammals of the Cretaceous (145–66 Mya) had both Meckel's cartilage and a mandible. In lobe-finned fishes and the early fossil tetrapods , the bone homologous to the mandible of mammals is merely the largest of several bones in the lower jaw. In such animals, it

2242-429: The jaws by the teeth; about the fourth year it is 140°. The fibrocartilage of the mandibular symphysis fuses together in early childhood. In the adult, the alveolar and subdental portions of the body are usually of equal depth. The mental foramen opens midway between the upper and lower borders of the bone, and the mandibular canal runs nearly parallel with the mylohyoid line. The ramus is almost vertical in direction,

2301-423: The late 19th century with new techniques for attaching prosthetics to a depreciated jawbone as well as bone grafting. In 2010, the first successful face transplant was conducted on a Spanish farmer after a self-inflicted gun accident ; this included the replacement of the entire mandible. The mandible can provide forensic evidence because its form changes over a person's life, and this can be used to determine

2360-410: The lower symphysis is a ridge called the mylohyoid line , where the mylohyoid muscle attaches; a small part of the superior pharyngeal constrictor muscle attaches to the posterior ridge, near the alveolar margin . Above the anterior ridge, the sublingual gland rests against a smooth triangular area, and below the posterior ridge, the submandibular gland rests in an oval depression. The ramus of

2419-403: The mandible and its teeth, making it a target of block anesthesia . Injecting the nerve is challenging due to the amount of surrounding soft tissue . American surgeon William Stewart Halsted developed a technique using a syringe and cocaine which was performed successfully by 1885. One fifth of facial injuries involve a mandibular fracture. Mandibular fractures are often accompanied by

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2478-413: The mandible is curved, and the front part gives structure to the chin . It has two surfaces and two borders. From the outside, the mandible is marked in the midline by a faint ridge, indicating the mandibular symphysis , the line of junction of the two halves of the mandible. This ridge divides below and encloses a triangular eminence, the mental protuberance (the chin), the base of which is depressed in

2537-414: The mandibular arch (occasionally noted also in partially edentulous cases). This resorption can occur to such an extent that the mental foramen is virtually on the superior border of the mandible, instead of opening on the anterior surface, changing its relative position. However, the more inferior body of the mandible is not affected and remains thick and rounded. With age and tooth loss, the alveolar process

2596-459: The mandibular canal, supplying sensation to the gums and teeth. Before passing through the mental foramen, the nerve divides into two terminal branches: incisive and mental nerves. The incisive nerve runs forward in the mandible and supplies the anterior teeth. The mental nerve exits the mental foramen and supplies sensation to the chin and lower lip. Males generally have squarer, stronger, and larger mandibles than females. The mental protuberance

2655-467: The mental foramen. By the tenth week, the portion of Meckel's cartilage which lies below and behind the incisor teeth is surrounded and invaded by the dermal bone (also known as the membrane bone). Somewhat later, accessory nuclei of cartilage make their appearance, as These accessory nuclei possess no separate ossific centers but are invaded by the surrounding dermal bone and undergo absorption. The inner alveolar border, usually described as arising from

2714-654: The most important towns in the municipal region of Acolman . It has many resources, among these: obsidian and pewter. Tepexpan has a church named Santa Maria Magdalena, located near the central plaza. It is one oldest of the region and it was built near the first years of the Spanish conquest. It has five districts: Anahuac 1 Sección ( Tepexpan ) Anahuac II Sección ( Tepexpan ) Chimalpa ( Tepexpan ) Los Reyes ( Tepexpan ) Paraje El Faro 19°37′09″N 98°56′07″W  /  19.61917°N 98.93528°W  / 19.61917; -98.93528 This article about

2773-453: The oldest Mexican. The skeleton was found lying face down with the arms under the chest and the legs drawn up to the stomach. The body most likely sank into the mud surrounding it, leaving the shoulder, back, and hips exposed, which might explain why those elements are missing. It is possible that the body was originally deposited in the lake. Alluvial deposits overlaid by layers of calcium carbonate, lake sediments, and recent deposits dated

2832-438: The past 20,000 years including several volcanic eruptions, changing water levels, and numerous types of vegetation. These environmental changes clearly affected populations living in the area. Today, Lake Texcoco is almost dried up. It sits on the northeast outskirts of Mexico City. AMS radiocarbon dates associated with sedimentary succession at Tepexpan show ages between 19,110±90 and 612±2214C years BP. New uranium-series date

2891-411: The powerful action of the masticatory muscles; but, the alveolar portion is the deeper of the two, and, consequently, the chief part of the body lies above the oblique line. The mandibular canal, after the second dentition, is situated just above the level of the mylohyoid line ; and the mental foramen occupies the position usual to it in the adult. The angle becomes less obtuse, owing to the separation of

2950-413: The prearticular bone. As the name implies, the majority of the teeth are attached to the dentary, but there are commonly also teeth on the coronoid bones, and sometimes on the prearticular. Most vertebrates exhibit a simpler scheme, as bones have either fused or vanished. In teleosts , only the dentary, articular, and angular bones remain, while in living amphibians , the dentary is accompanied only by

3009-607: The prearticular, and, in salamanders , one of the coronoids. The lower jaw of reptiles has only a single coronoid and splenial, but retains all the other primitive bones except the prearticular and the periosteum. In birds, the various bones have fused into a single structure. In mammals, most have disappeared, leaving only the mandible. As a result, there is only articulation between the mandible and temporal bones, as opposed to articulation between articular and quadrate bones . An intermediate stage can be seen in some therapsids , in which both points of articulation are present. Aside from

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3068-414: The ramus, and then horizontally forward in the body, where it is placed under the alveoli , with small openings for nerves. 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. In the posterior two-thirds of the bone the canal is situated nearer the internal surface of the mandible; and in

3127-410: The second year, near the alveolar margin. The body becomes elongated in its whole length, but more especially behind the mental foramen, to provide space for the three additional teeth developed in this part. The depth of the body increases owing to increased growth of the alveolar part, to afford room for the roots of the teeth, and by thickening of the subdental portion which enables the jaw to withstand

3186-465: The site where Tepexpan Man was found to about 8,000 to 10,000 years ago. Excavations revealed the remains of five mammoths which were found near the skeleton and associated with obsidian flakes. Therefore, it was originally believed that Tepexpan Man dated to about 10,000 years ago. However, years later, researchers revisited the skeleton and dated the remains using radiocarbon methods. It was then found to be closer to 2,000 years old. Dr. Silvia Gonzalez,

3245-461: The skeleton to 4,700±200 years BP, which would indicate a Holocene age. The sedimentary succession was studied through isotope analysis, diatoms, organic geochemistry, and tephrochronology. These lines of evidence suggest that there were large changes around Lake Texcoco in terms of the balance between aquatic and terrestrial plants, C3 and C4 plants, saline, alkaline and freshwater conditions, volcanic activity, reworking of lake sediments, and input from

3304-407: The socket of the first deciduous molar tooth. The angle is obtuse (175°), and the condyloid portion is nearly in line with the body. The coronoid process is of comparatively large size, and projects above the level of the condyle. After birth, the two segments of the bone become joined at the symphysis, from below upward, in the first year; but a trace of separation may be visible in the beginning of

3363-491: The superior (upper) and posterior projection from the ramus, makes the temporomandibular joint with the temporal bone. The coronoid process, superior and anterior projection from the ramus. This provides attachment to the temporal muscle . Teeth sit in the upper part of the body of the mandible. The frontmost part of teeth is more narrow and holds front teeth. The back part holds wider and flatter (albeit grooved) teeth primarily for chewing food. The word mandible derives from

3422-512: The temporomandibular joint prevents the mandible from moving posteriorly, making the condylar neck particularly vulnerable to fractures. Further, various jawbone damage can cause temporomandibular joint dysfunction , with symptoms including pain and inflammation . The jawbone can also become deviated in mandibular lateral displacement , a condition which can offset facial symmetry and cause posterior crossbite . The mandibular alveolar process can become resorbed when completely edentulous in

3481-406: Was published in the 1947 issue of The Science Newsletter claims that the individual was at least 40 at the time of death. This was determined by "united seams in the skull" (referring to sutures), and fused epiphyses in long bones. In his preliminary report, Helmut de Terra claims that "The other bones, in conjunction with the skull, indicate that the person was of male sex." Based on DNA analysis,

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