Page:Structure and functions of the body; a hand-book of anatomy and physiology for nurses and others desiring a practical knowledge of the subject (IA structurefunctio00fiskrich).pdf/60

 organs of special sense. Many delicate muscles control the facial expression which, consciously or unconsciously, reflects the character of their owner.

Surgically the most important of the facial bones are the two superior maxillary bones, because of the number of diseases to which they are liable. They meet in front, together forming the upper jaw, and with the malar bone help form the lower part of the orbit of the eye. They are cuboid in shape and are hollowed out into a pyramidal cavity called the antrum of Highmore, which opens by a small orifice into the middle nasal meatus and which sometimes becomes infected and has to be tapped. The nasal process for articulation with the frontal and nasal bones has, at its lower edge, a crest for the inferior turbinated bone, and close beside this on the inside, extending down from the upper edge, is a deep groove which, with the lachrymal and inferior turbinated bones, helps to form the lachrymal canal for the nasal tear duct. The bones give attachment to many small muscles, connected for the most part with the nose and mouth, of which the masseter is the only important one.

The two malar or cheek bones are small quadrangular bones, which form the prominences of the cheeks and help form the orbits of the eyes. Projecting backward from each is a zygomatic process for articulation with the zygomatic process of the temporal bone, while a maxillary process extends downward for articulation with the superior maxillary. Here again the most important muscle attached is the masseter. If the malar bone is crushed great deformity results.

The lachrymal bones are two small bones, about the size and shape of a finger-nail, situated at the front of the inner wall of the orbit. At the external edge is a groove which lodges the lachrymal sac above and forms part of the lachrymal canal below.

The two palate bones are at the back of the nasal fossæ and help to form the floor of the nose, the roof of the mouth, and the orbit. Each has a vertical and a hori