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 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 the jaws by the teeth; about the fourth year it is 140°. 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, the angle measuring from 110° to 120°, also the adult condyle is higher than the coronoid process and the sigmoid notch becomes deeper. 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 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. changes in the mandible with age newborn childhood adult old age function the medial and lateral pterygoid muscles; the zygomatic arch and a portion of the ramus of the mandible have been removed 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. condyloid process, superior (upper) and posterior projection from the ramus, which makes the temporomandibular joint with the temporal bone 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 teeth primarily for chewing food. these teeth also often have wide and sometimes deep grooves on the surfaces. clinical significance fracture main article: mandibular fracture frequency by location one fifth of facial injuries involve a mandibular fracture. mandibular fractures are often accompanied by 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. causes of mandibular fractures cause percentage motor vehicle accident 40% assault 10% fall 10% sport 5% other 5% the mandible may be dislocated anteriorly (to the front) and inferiorly (downwards) but very rarely posteriorly (backwards). the articular disk of the temporomandibular joint prevents the mandible from moving posteriorly, making the condylar neck particularly vulnerable to fractures. the mandibular alveolar process can become resorbed when completely edentulous in 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 is absorbed so that the mandibular canal becomes nearer the superior border. sometimes with excessive alveolar process absorption, the mandibular canal disappears entirely and leaves the inferior alveolar nerve without its bony protection, although it is still covered by soft tissue. forensic medicine when remains of humans are found, the mandible is one of the common findings, sometimes the only bone found. skilled experts can estimate the age of the human upon death because the mandible changes over a person's life. other vertebrates sperm whale 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 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. finally a set of three narrow coronoid bones lie above 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 as well. this complex primitive pattern has, however, been simplified to various degrees in the great majority of vertebrates, as bones have either fused or vanished entirely. in teleosts, only the dentary, articular, and angular bones remain, while in living amphibians, the dentary is accompanied only by 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. while, in birds, these various bones have fused into a single structure, in mammals most of them have disappeared, leaving an enlarged dentary as the only remaining bone in the lower jaw – the mandible. as a result of this, the primitive jaw articulation, between the articular and quadrate bones, has been lost, and replaced with an entirely new articulation between the mandible and the temporal bone. an intermediate stage can be seen in some therapsids, in which both points of articulation are present. aside from the dentary, only few other bones of the primitive lower jaw remain in mammals; the former articular and quadrate bones survive as the malleus and the incus of the middle ear. finally, the cartilaginous fish, such as sharks, do not have any of the bones found in the lower jaw of other vertebrates. instead, their lower jaw is composed of a cartilagenous structure homologous with the meckel's cartilage of other groups. this also remains a significant element of the jaw in some primitive bony fish, such as sturgeons. society and culture in the book of judges, samson used a donkey's jawbone to kill a thousand philistines. dental remains of adolf hitler including part of a mandible with teeth were the solitary physical evidence used to confirm his death in 1945. the soviet account published in 1968 describes and photographically depicts the jawbone as being broken off at the alveolar process. additional images lateral view alveolar process