Bones of the face and the skull

The skull is of a spheroidal figure, compressed on the sides, broader behind ihan before, and supported by its base on the vertebral column.

It is divided by anatomists into two parts, the cranium and the face ; the former being composed of eight bones, viz., the occipital, two 'parietal, the frontal, two temporal, the sphenoid, and the ethmoid ; the latter is made up of fourteen bones, viz., two superior maxillary, two malar, two ossa nasi, two ossa palati, two ossa unguis, two inferior turbinated bones, the vomer, and inferior maxilla ; the frontal bone is so situated as to be common to the cranium and face. The bones of the ear are not included in this enumeration, as they belong rather to a special organ than to the skeleton considered as the framework of the body.

The bones of the face are fourteen in number

In order to study the interior of the skull it is necessary to make sections in three directions, sagittal, coronal and horizontal.

The lacrimal bones (French: os lacrymal) are extremely thin and delicate, quadrilateral in shape, and situated at the anterior part of the inner wall of the orbit. They are the smallest of the facial bones.

The skull, when viewed from above, presents an oval outline; the posterior part is broader than the anterior. The bones seen in this view are the frontal, parietals and the interparietal portion of the occipital. In a skull of average width the zygomata come into view, but in very broad skulls they are obscured.

The mandible [mandibula] or lower jaw-bone is the largest and strongest bone of the face. It supports the mandibular teeth, and by means of a pair of condyles, moves on the skull at the mandibular fossae of the temporal bones. It consists of a horizontal portion — the body —  strongly curved, so as to somewhat resemble in shape a horseshoe, from the ends of which two branches or rami ascend almost at right angles.

The occipital bone, (lat.: os occipitis, french: Os occipital) is situated at the posterior part of the base of the skull; broad behind, much narrowed before, of a trapezoid figure, presenting two surfaces, four borders, and four angles. To place the bone in its natural position, hold it so that the great foramen and the articulating processes beside it shall look directly downwards; the thick process in front of the foramen will then project forwards into the base of the Skull, Whilst the broad expanded part behind it arches upwards and a little forwards, forming the posterior wall of the Cavity. 

The zygomatic [os zygomaticum] or malar bone forms the prominence known as the cheek and joins the zygomatic process of the temporal with the maxilla. It is quadrangular in form with the angles directed vertically and horizontally. The malar (or external) surface is convex and presents one or two small orifices for the transmission of the zygomatico-facial nerves and vessels. It is largely covered by the orbicularis oculi and near the middle is slightly ele- vated to form the malar tuberosity, which gives origin to the zygomaticus and zygomatic head of quadrate muscle of upper lip.

This is the u-shaped bone, so named from some resemblance to the Greek letter v. It is occasionally called the lingual bone, from its important relations with the tongue; it is situated at the base of the tongue, and may be felt between the chin and the thyroid cartilage. It consists of a body, two cornua, and two cornicula.

The nasal bones are two small oblong bones situated at the upper part of the face and forming the bridge of the nose. Each bone is thicker and narrower above, thinner and broader below, and presents for examination two surfaces and four borders.

The frontal bone, (os frontis, coroaale,) situated at the anterior part of the skull, and upper part of the face, is divisible into two parts (frontal and orbital), differing in size and position: of these, one extends upwards towards the vertex, forming three-fourths of the extent of the bone; the other, inferior and horizontal in its direction, forms the roof of the orbits. To place the bone in its natural position, hold it so that the orbital plates shall look downwards, and the smooth convex surface forwards. 

These are two oblong bones situated in the middle line at the upper part of the face and forming the bridge of the nose. Each bone has two surfaces and four borders. The facial surface is concave from above downwards, but convex from side to side. Near its centre is a foramen for the transmission of a small tributary to the facial vein. The posterior or nasal surface is concave laterally and traversed by a longitudinal groove for the nasal branch of the ophthalmic nerve.

The adult temporal bone (French: os temporal) consists of three parts, so firmly united as to afford little trace of its complex origin. At birth the three parts are easily separable as the squamosal, petrosal, and tympanic.

The parietal bones (Latin : ossa parietalia, verticis, bregmatis ; french : os pariétal) form a principal part of the roof of the skull; they are of a square form, convex externally, concave internally, and present each two surfaces and four borders. The external surface, rises towards its middle, where it presents a slight elevation, called the parietal eminence, 5 below which is a curved line, forming part of the temporal ridge, and bounding a flat surface (planum semicirculare), which forms a part of the temporal fossa. At the upper and back part of the bone, usually about two lines from the sagittal suture, is a small hole, 6 (foramen parietale) which transmits a communicating vein; its position is exceedingly variable; even its existence is not constant. 

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