The pathology and surgical treatment of tumors . d gives rise to a portionof the ala of the nostril and the correspondingpremaxilla. These globular processes fuse to-gether in the middle line to form the centralpiece, or philtrum, of the upper lip. The elon-gation of the fronto-nasal process necessarilylengthens the orbito-nasal fissures. Eventuallythe sides of the fronto-nasal plate coalesce super-ficially with the maxillary processes in such a way as to leave a clefton each side, which becomes the orbit, the line of union being perma-nently indicated in the adult by the naso-facial sulcus or
The pathology and surgical treatment of tumors . d gives rise to a portionof the ala of the nostril and the correspondingpremaxilla. These globular processes fuse to-gether in the middle line to form the centralpiece, or philtrum, of the upper lip. The elon-gation of the fronto-nasal process necessarilylengthens the orbito-nasal fissures. Eventuallythe sides of the fronto-nasal plate coalesce super-ficially with the maxillary processes in such a way as to leave a clefton each side, which becomes the orbit, the line of union being perma-nently indicated in the adult by the naso-facial sulcus or groove, andindicated still more deeply by the lachrymal duct, which is a persistentportion of the original orbito-nasal fissure. The union of the fronto-nasal plate with the maxillary processes completes the nose, cheeks,and upper lip (Sutton). From the foregoing description of the development of the face itwill be understood that dermoid cysts will appear in certain definitepositions, such as the inner and outer angles of the orbit, the upper. Fig. 455 —Head of an early-human embryo, showing thedisposition of the facial fissures(after His). PATHOLOGY AND TREATMENT OF TUMORS. eyelid, in the naso-facial sulcus, on the cheek slightly posterior to the angle of the mouth, in the middleline of the chin, and on the cysts in all these localitiesseldom exceed a filbert in size. Theyoften contain hair, and they some-times contain pure oil. The under-lying bone shows a shallow or deepdepression after their removal. Theyare firmly attached to the bone ; theyare frequently congenital; fluctuationis distinct; the skin overlying them isnormal. The most frequent locationof dermoid cysts of the face is at theouter angle of the eye (Fig. 456). Inthis situation the orbital arch of thefrontal bone often shows a depressiondeep enough to hold one-half of thecyst. If the cyst occupies the innerangle of the eye, the nasal process of the frontal bone suffers from pres-sure-atrophy. The
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectneoplas, bookyear1895
