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Meckel's cartilage arises from the first pharyngeal arch. The dorsal end of each cartilage is connected with the ear-capsule and is ossified to form the malleus ; the ventral ends meet each other in the region of the mandibular symphysis , and are usually regarded as undergoing ossification to form that portion of the mandible which contains ...
The mandible forms as a bone (ossifies) from Meckel's cartilage, which forms the cartilaginous bar of the mandibular arch and, dorsally, parts of the middle ear. [15] The two sides of the jawbone are inferiorly fused at the mandibular symphysis (the chin) during the first year of life. [6]
Premaxilla, maxilla, mandible (only as a model for mandible not actual formation of mandible), zygomatic bone, part of the temporal bone, [19] the incus, and the malleus of the middle ear, also Meckel's cartilage and the sphenomandibular ligament. Trigeminal nerve (part of V2 [20] and V3) Maxillary artery, external carotid artery, Vidian artery
The mandible and lower lip derive from it. [1] The mesenchymal cells within the mandibular prominence condense to form Meckel's cartilage. [2]
The function of the sphenomandibular ligament is to limit distension of the mandible in an inferior direction. It is slack when the temporomandibular joint (TMJ) is in closed position; it is taut when the condyle of the mandible is situated anterior to the temporomandibular ligament. [2]
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 cartilaginous 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. [11]
Alongside the tooth whorl, the specimen preserves a palatoquadrate (forming the upper jaw), Meckel's cartilage (forming the lower jaw), and a robust labial cartilage bracing the tooth whorl. All of these structures are composed of prismatic calcified cartilage, as with modern chondrichthyans.
In pig embryos, the mandible ossifies on the side of Meckel's cartilage, while the posterior part of that cartilage is ossified into the incus. In later development, this portion detaches from the rest of the cartilage and migrates into the middle ear. [7]