zygoma

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The zygomatic bone.
2. n. The zygomatic arch.
3. n. The zygomatic process.

Century Dictionary and Cyclopedia

1. n. The bony arch or arcade of the cheek, formed by the malar or jugal bone and its connections: socalled because it serves to connect bones of the face with those of the skull about the ear. In mammals, including man, the zygoma consists of a malar bone connected behind with the squamosal bone, usually by a zygomatic process of the latter, and abutting in front against a protuberance of the superior maxillary bone, or of the frontal or the lacrymal bone, or any of these. It is usually a stout bony arch, sometimes with a strong descending process, giving principal origin to a masseter muscle, and bridging over the temporal muscle. It is sometimes a slender rod, and may be imperfect, as in shrews. The part taken in its for mation by the malar bone is very variable in extent. (See cut under skull.) Below mammals the construction of the zygoma posteriorly is entirely altered. In birds the arch is articulated there with the quadrate bone, or suspensorium of the lower jaw, representing the malleus of a mammal, aud an additional bone, the quadratojugal, intervenes between the quadrate and the malar proper. In such cases the anterior connection is more particularly with the maxillary bone, or with this and the lacrymal, and the zygoma is generally a slender rod-like structure. (See cut under Gallinæ.) In reptiles further modifications occur, such as the completion of the arch behind by union of the jugal bone with the postfrontal and squamosal; or there may be no trace of a structure to which the term zygoma is properly applicable, as in the Ophidia, in which there is no jugal or quadratojugal bone. Among batrachians, as the frog, a zygomatic arch is represented by the connection of the maxillary bone, by means of a quadratojugal bone, with a bone called temporomastoid (see cuts there and under Anura). In any case a zygoma consists of a suborbital or postorbital series of ossifications in membrane, or membrane-bones, developed on the outer side of the maxillary arch of the embryo (the same that gives rise to the pterygopalatine bar), and when best differentiated is represented by lacrymal, maxillary, jugal, and quadratojugal bones; and its connection with the sphenoid, as occurs in man, is quite exceptional.
2. n. The malar or jugal bone itself, without its connections.
3. n. The cavity under the zygomatic process of the temporal bone; the zygomatic fossa.

Wiktionary

1. n. anatomy The cheekbone.

GNU Webster's 1913

1. n. The jugal, malar, or cheek bone.
2. n. The zygomatic process of the temporal bone.
3. n. The whole zygomatic arch.

WordNet 3.0

1. n. the slender arch formed by the temporal process of the cheekbone that bridges to the zygomatic process of the temporal bone