| Meckel's cartilage | |
|---|---|
 Head and neck of a human fetus at eighteen weeks, with Meckel's cartilage and hyoid bar exposed. | |
 Mandible of human fetus 95 mm (3.7 in) long. Inner aspect. Nuclei of cartilage stippled. | |
| Details | |
| Precursor | First pharyngeal arch |
| Gives rise to | Incus,malleus |
| Identifiers | |
| Latin | cartilago arcus pharyngei primi |
| TE | cartilage_by_E4.0.3.3.3.1.3 E4.0.3.3.3.1.3 |
| Anatomical terminology | |
In humans, the cartilaginous bar of themandibular arch is formed by what are known asMeckel's cartilages (right and left; also known asMeckelian cartilages), above which theincus andmalleus are located. Meckel's cartilage arises from thefirst pharyngeal arch.
The dorsal end of each cartilage is connected with the ear-capsule and is ossified to form themalleus; the ventral ends meet each other in the region of themandibular symphysis, and are usually regarded as undergoingossification to form that portion of themandible which contains theincisor teeth.
The intervening part of the cartilage disappears; the portion immediately adjacent to the malleus is replaced by fibrous membrane, which constitutes thesphenomandibular ligament, while from the connective tissue covering the remainder of the cartilage the greater part of the mandible is ossified.
Johann Friedrich Meckel, the Younger discovered this cartilage in 1820.
Meckel's cartilage is a piece ofcartilage from which the mandibles (lower jaws) ofvertebrates evolved. Originally it was the lower of two cartilages which supported the firstbranchial arch in earlyfish. Then it grew longer and stronger, and acquired muscles capable of closing the developing jaw.[1]
In early fish and inchondrichthyans (cartilaginous fish such assharks), Meckel's cartilage continued to be the main component of the lower jaw. But in the adult forms ofosteichthyans (bony fish) and their descendants (amphibians,reptiles,birds, andmammals), the cartilage is covered in bone – although in theirembryos the jaw initially develops as Meckel's cartilage. In alltetrapods the cartilage partially ossifies (changes to bone) at the rear end of the jaw and becomes thearticular bone, which forms part of the jaw joint in all tetrapods exceptmammals.[1]
In some extinct mammal groups likeeutriconodonts, Meckel's cartilage still connected otherwise entirely modern ear bones to the jaw.[2]
This article incorporates text in thepublic domain frompage 66 of the 20th edition ofGray's Anatomy(1918)
