This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The upper jaw carries the upper teeth and contains the maxillary sinus or antrum of Highmore. The affections of the antrum will be alluded to in the chapter on the nose (see page 103). Fractures of the superior maxilla involve the nasal process, the alveolar process, or pass transversely through the body of the bone. The nasal process is sometimes broken in fractures of the nose. In this injury, the lachrymal canal and sac may be injured and the flow of tears through them prevented, causing the tears to run over the cheek.
Fractures of the alveolar process are common enough as a result of blows and extracting teeth. These fractures, as they communicate with the mouth through the broken gums or mucous membrane or tooth socket, are necessarily compound, and consequently become infected from the mouth and suppurate. This may cause necrosis of the fragment, but the blood supply of the jaws is so good that death of a fragment is rare, and it is not customary to remove fragments not completely detached. The front wall is sometimes driven in.
Fractures occasionally occur in which the line passes through one or both superior maxillary bones from below the malar bone into the nose. If this fracture passes completely backward, it detaches the lower portion of the palate bone and pterygoid processes of the sphenoid bone. The fragment in such cases has a tendency to slip backward. It can be replaced by inserting a hook through the mouth and behind the soft palate and pulling the fragment forward. This injury is produced by a blow on the anterior portion of one or both bones, passing downward and backward. In order to determine the existence of fracture, Guerin recommended inserting the finger in the mouth and feeling for the pterygoid plates. The hamular process of the internal pterygoid plate can readily be felt about one centimetre above and behind the last upper molar tooth. Fractures in the neighborhood of the first and second molar teeth are liable to open the antrum, as the roots of these teeth project into it.
Tumors of the antrum may necessitate a resection of the superior maxilla of one side. Hey-felder was the first to remove both superior maxillae, in 1844: this was before the discovery of anaesthesia. In removing one superior maxilla, the incision known as Fer-gusson's is used. This is made through the middle of the upper lip, around the ala of the nose to the inner canthus of the eye, thence outward along the lower border of the orbit to the malar bone. The bleeding from this incision is free. The coronary arteries should be looked for near the mucous surface of the lip toward its free edge. Bleeding will also occur from the lateralis nasi and the angular arteries. The soft parts are raised from the bones as far back as the masseter muscle. This is just about level with the outer edge of the bony orbit. In doing so the infra-orbital nerve and artery will be divided. The artery is not large but may bleed freely. The fibrous floor of the orbit is raised and the attachment of the inferior oblique muscle loosened. The malar bone is sawed downward and outward opposite the sphenomaxillary fissure, and the division completed with forceps. The nasal portion of the superior maxilla is sawed through from the orbit into the nose. The soft parts of the roof of the mouth are divided in the median line to the posterior edge of the hard palate, and thence along its edge to the last molar tooth. The soft palate is firmly attached to the hard palate and has to be detached with scissors. An incisor tooth is then drawn, and the bony palate sawed through from the nose into the mouth. The bone with the tumor is wrenched loose with lion-jawed forceps. The union between the posterior portion of the superior maxilla and the pterygoid processes of the sphenoid is not bony, but fibrous, so that the bone is torn away from the processes and the latter are left behind. As the bone comes away, the maxillary nerve should be cut. The bleeding which follows is from the infra-orbital, superior alveolar (posterior dental), and posterior palatine arteries, branches of the internal maxillary. It is not so free as might be expected, provided preliminary ligation of the external carotid has been performed. It will be observed that the facial nerve is not touched nor is the parotid duct wounded.